Class 12

Odisha State Board CHSE Odisha Class 12 Psychology Solutions Unit 2 Long Answer Questions Part-2.

CHSE Odisha 12th Class Psychology Unit 2 Long Answer Questions Part-2

Long Questions With Answers

Question 1.
What are the Signs and Symptoms of Stress?
Answer:
The way we respond to stress varies depending upon our personality, early upbringing and life experiences. Everyone has their own pattern of stress response. So the warning signs may vary, as may their intensity. Some of us know our pattern of stress response and can gauge the depth of the problem by the nature and severity of our own symptoms or changes in behavior.

These symptoms of stress can be physical, emotional and behavioral. Any of the symptoms can indicate a degree of stress which, if left unresolved, might have serious implications, that are often unavoidable such as air pollution, crowding, noise, the heat of the summer, winter cold, etc. Another group of environmental stresses are catastrophic events or disasters such as fire, earthquake, floods, etc.

Question 2.
Discuss the Types of Stress.
Answer:
The three major types of stress, viz. physical and. environmental, psychological, and social are listed. It is important to understand that all these types of stress are interrelated.

Physical and Environmental Stress :
Physical stresses are demands that change the state of our body. We feel strained when, we overexert ourselves physically, lack a nutritious diet, suffer an injury, or fail to get enough sleep. Environmental stresses are aspects of our surroundings.

Psychological Stress :
These are stresses that we generate ourselves in our minds. These are personal and unique to the person experiencing them and are internal sources of stress. We worry about problems, feel anxiety, or become depressed. These are, not only symptoms of stress, but they cause further stress for us. Some of the important sources of psychological stress are frustration, conflicts, internal and social pressures, etc.

Frustration:
Frustration results from the blocking of needs and motives by something “or someone that hinders us from achieving the desired goal. There could be a number of causes of frustration such as social discrimination, interpersonal hurt, low grades in school, etc.

Conflicts:
Conflicts may occur between two or more incompatible needs or motives, e.g. whether to study dance or psychology. You may want to continue your studies or take up a job. There may be a conflict of values when you are pressurised to take any action that may be against the values held by you.

Internal pressures:
Internal pressures stem from beliefs based upon expectations from inside us to ourselves such as, ‘I must do everything perfectly. Such expectations can only lead to disappointment. Many of us drive ourselves ruthlessly towards achieving unrealistically high standards in achieving our goals.

Social pressures:
Social pressures may be brought about from people who make excessive demands on us. This can cause even greater pressure when we have to work with them. Also, there are people with whom we face interpersonal difficulties, ‘a personality clash’ of sorts.

Social Stress :
These are induced externally and result from our interaction with other people. Social events like death or illness in the family, strained relationships, and trouble with neighbors are some Examples of social stresses. These social stresses vary widely from person to person. Attending parties may be stressful for a person who likes to spend quiet evenings at home while an outgoing person may find staying at home in the evenings stressful.

Question 3.
Write the Sources of Stress.
Answer:
A wide range of events and conditions Can generate stress. Among the most important of these are major stressful life events, such as the death of a loved one or personal.
Life Events:
Changes, both big and small, sudden and gradual affect our life from the moment we are born. We learn to cope with small, everyday changes but major life events can be stressful because they disturb our routine and cause upheaval. If several of these life events that are planned (e.g. moving into a new house) or unpredicted (e.g. break-up of a long-term relationship) occur within a short period of time, we find it difficult to cope with them and will be more prone to the symptoms of stress.
A Measure of Stressful Life Events

Life Events Mean Stress Score
Death of a close family member	66
Unexpected accident or trauma	53
Illness of a family member	52
Break-up with friend	47
Appearing for examinations	43
Change in eating habits	27

The mean number of stressful life events experienced over a period of one year. Holmes and Rahe developed a life event measure of stress. A measure of stressful life events based on the above scale known as the Presumptive Stressful Life Events Scale has been developed for the Indian population by Singh, Kaur and Kaur. It is a self-rating questionnaire made up of fifty-one life changes, that a person may have experienced. Each of these life events is assigned a numerical value in terms of their severity.

For example, the death of one’s spouse is assigned 95, personal illness or injury 56, failure in examination 43, appearing for examination or interview 43, and change in sleeping habits 33, as the mean stress score. Both positive and negative events are taken, believing that both kinds of changes cause stress. The respondent’s stress score is the weighted sum of all the items/life change events in the past one year checked by her/him. Some sample items of without producing overt physical or mental illness is approximately two.

However, the correlations between life events and susceptibility to any particular illness is low, indicating a weak association between life events and stress. It has been argued as to whether life events have caused some stress-related illness or whether stress caused life events and illness. The impact of most life events varies from person to person.

Factors such as age at which the event was first experienced, frequency of occurrence, duration of the stressful event and social support must be studied in evaluating the relationship between stressful life events and the subsequent illness episode, injury, the annoying frequent hassles of everyday life and traumatic events that affect our lives.

Hassles :
These are the personal stresses we endure as individuals, due to the happenings in our daily life, such as noisy surroundings, commuting, quarrelsome neighbors, electricity and water shortage, traffic snarls and so on. Attending to various emergencies are daily hassles experienced by a housewife. There are some jobs in which daily hassles are very frequent. These daily hassles may sometimes have devastating consequences for the individual who is often the one coping alone with them as others may not even be aware of them as outsiders. The more stress people report as a result of daily hassles, the poorer is their psychological well-being.

Traumatic Events :
These include being involved in a variety of extreme events such as a fire, train or road accident, robbery, earthquake, tsunami, etc. The effects of these events may occur after some lapse of time and sometimes persist as symptoms of anxiety, flashbacks, dreams and intrusive thoughts, etc. Severe trauma can also strain relationships. Professional help will be needed to cope with them especially if they persist for many months after the event is over.

Question 4.
What is the Effects of Stress on Psychological Functioning and Health,
Answer:
Many of the effects are physiological in nature, however, other changes also occur inside stressed individuals. There are four major effects of stress associated with the stressed state, viz. emotional, physiological, cognitive, and behavioral.

Emotional Effects :
Those who suffer from stress are far more likely to experience mood swings and show erratic behavior that may alienate them from family and friends. In some cases this can start a vicious circle of decreasing confidence, leading to more serious emotional problems. Some examples are feelings of anxiety and depression, increased physical tension, increased psychological tension and mood swings. Box 3.2 presents the phenomenon of ‘Examination Anxiety’.

Physiological Effects :
When the human body is placed under physical or psychological stress, it increases the production of certain hormones, such as adrenaline and cortisol. These hormones produce marked changes in heart rate, blood pressure levels, metabolism and physical activity. Although this physical reaction will help us to function more effectively when we are under pressure for short periods of time, it can be extremely damaging to the body in the long-term effects. Examples of physiological effects are release of epinephrine and norepinephrine, slowing down of the digestive system, expansion of air passages in the lungs, increased heart rate, and constriction of blood vessels.

Cognitive Effects :
If pressures due to stress continue, one may suffer from mental overload. This suffering from high level of stress can rapidly cause individuals to lose their ability to make sound decisions. Faulty decisions made at home, in career, or at the workplace may lead to arguments, failure, financial loss or even loss of job. Cognitive effects of stress are poor concentration and reduced short-term memory capacity.

Behavioral Effects:
Stress affects our behavior in the form of eating less nutritional food, increasing intake of stimulants such as caffeine, excessive consumption of cigarettes, alcohol and other drugs such as tranquilizers etc. Tranquilizers can be addictive and have side effects such as loss of concentration, poor coordination and dizziness. Some of the typical behavioral effects of stress seen are disrupted sleep patterns, increased absenteeism, and reduced work performance.

Stress and Health :
You must have often observed that many of your friends (maybe including yourself as well!) fall sick during examination time. They suffer from stomach upsets, body aches, nausea, diarrhea and fever etc. You must have also noticed that people, who are unhappy in their personal lives fall sick more often than those who are happy and enjoy life. Chronic daily stress can divert an individual’s attention from caring for herself or himself.

When stress is prolonged, it affects physical health and impairs psychological functioning.People experience exhaustion and attitudinal problems when the stress due to demands from the environment and constraints are too high and little support is available from family and friends. Physical exhaustion is seen in the signs of chronic fatigue, weakness and low energy. Mental exhaustion appears in the form of irritability, anxiety, feelings of helplessness and hopelessness.

This state of physical, emotional and psychological exhaustion is known as burnout. There is also convincing evidence to show that stress can produce changes in the immune system and increase the chances of someone becoming ill. Stress has been implicated in the development of cardiovascular disorders, high blood pressure, as well as psychosomatic disorders including ulcers, asthma, allergies and headaches. Researchers estimate that stress plays an important role in fifty to seventy percent of all physical illnesses. Studies also reveal that sixty percent of medical visits are primarily for stress-related symptoms.

General Adaptation Syndrome :
What happens to the body when stress is prolonged? Selye studied this issue by subjecting animals to a variety of stressors such as high temperature, X-rays, and insulin injections, in the laboratory over a long period of time. He also observed patients with various injuries and illnesses in hospitals. Selye noticed a similar pattern of bodily response in all of them. He called this pattern the General Adaptation Syndrome (GAS). According to him, GAS involves three stages: alarm reaction, resistance and exhaustion.

Alarm reaction stage :
The presence of a noxious stimulus or stressor leads to the activation of the adrenal pituitary- cortex system. This triggers the release of hormones producing the stress response. Now the individual is ready for fight or flight.

Resistance stage :
If stress is prolonged, the resistance stage begins. The parasympathetic nervous system calls for more cautious use of the body’s resources. The organism makes efforts to cope with the threat, as through confrontation.

Exhaustion stage:
Continued exposure to the same stressor or additional stressors drains the body of its resources and leads to the third stage of exhaustion. The physiological systems involved in alarm reaction and resistance become ineffective and susceptibility to stress-related diseases such as high blood pressure becomes more likely. Selye’s model has been criticized for assigning a very limited role to psychological factors in stress. Researchers have reported that the psychological appraisal of events is important for the determination of stress. How people respond to stress is substantially influenced by their perceptions, personalities and biological constitutions.

Stress and the Immune System:
Stress ean cause illness by impairing the workings of the immune system. The immune system guards the body against attackers, both from within and outside.

Psychoneuroimmunology:
Psychoneuroimmunology focuses on the links between the mind, the brain and the immune system. It studies the effects of stress on the immune system. How does the immune system work? The white blood cells (leucocytes) within the immune (antigens) such as viruses. It also leads to the production of antibodies. There are several kinds of white blood cells or leucocytes within the immune system, including T cells, B cells and natural killer cells. T cells destroy invaders, and T-helper cells increase immunological activity. It is these T-helper cells that are attacked by the Human Immuno Deficiency Virus (HIV), the virus causing Acquired Immuno Deficiency Syndrome (AIDS). B cells produce antibodies.

Natural killer cells are involved in the fight against both viruses and tumors, Stress can affect natural killer cell cytotoxicity, which is of major importance in the defense against various infections and cancer. Reduced levels of natural, killer cell cytotoxicity have been found in people who are highly stressed, including students facing important examinations, bereaved persons, and those who are severely depressed. Studies reveal that immune functioning is better in individuals receiving social support. Also, changes in the immune system will have more effect on health among those whose immune systems are already weakened.

Figure 3.4 depicts this sequence comprising negative emotions, release of stress hormones which lead to the weakening of the immune system, thereby affecting mental and physical health. Psychological stress is accompanied by negative emotions and associated behaviors, including depression, hostility, anger and aggression. Negative emotional states are of particular concern to the study of the effects of stress on health. The incidence of psychological disorders, such as panic attacks and obsessive behavior increases with the build-up of long-term stress. Worries can reach such a level that they surface as a frightening, painful physical sensation, which can be mistaken for a heart attack.

People under prolonged stress are more prone to irrational fears, mood swings and phobias, and may experience fits of depression, anger and irritability. These negative emotions appear to be related to the function of the immune system. Our ability to interpret our world and to invest that interpretation with personal meaning and emotion have a powerful and direct effect on the body. Negative moods have been associated with poorer health outcomes. Feelings of hopelessness are related to the worsening of disease and increased risk of injury and death due to various causes.

Lifestyle :
Stress can lead, to unhealthy lifestyles or health-damaging behavior. Lifestyle is th,e overall pattern of decisions and behaviors that determine a person’s health and quality of life. Stressed individuals may be more likely to expose themselves to pathogens, which are agents causing physical illness. People who are stressed have poor nutritional habits, sleep less and are likely to engage in other health-risking behaviors like smoking and alcohol abuse. Such health-impairing behaviors develop gradually and are accompanied by pleasant experiences temporarily.

However, we tend to ignore their long-term damaging effects and underestimate the risk they pose to our lives. Studies have revealed that health-promoting behavior like a balanced diet, regular exercise, family support, etc. play an important role in good health. Adhering to a lifestyle that includes a balanced low-fat diet, regular exercise and continued activity along with positive thinking enhances health and longevity. The modem lifestyle of excesses in eating, drinking and the so called fast-paced good life has led to violation of basic principles of health in some of us, as to what we eat, think or do with our lives.

Question 5.
How to cope up with Stress?
Answer:
In recent years the conviction has grown that it is how we cope with stress and not the stress one experiences that influence our psychological well-being, social functioning and health. Coping is a dynamic situation-specific reaction to stress. It is a set of concrete responses to stressful situations or events that are intended to resolve the problem and reduce stress. The way we cope with stress often depends on rigid deep-seated beliefs, based on experience, e.g. when caught in a traffic jam we feel angry because we believe that the traffic ‘should’ move faster.

To manage stress we often need to reassess the way we think and learn coping strategies. People who cope poorly with stress have an impaired immune response and diminished activity of natural killer cells. Individuals show consistent individual differences in the coping strategies they use to handle stressful situations. These can include both overt and covert activities.

The three coping strategies given by Endler and Parker are:

Task-oriented Strategy :
This involves obtaining information about the stressful situation and about alternative courses of action and their probable outcome; it also involves deciding priorities and acting so as to deal directly with the stressful situation. For example, schedule my time better, or think about how I have solved similar problems.

Emotion-oriented Strategy:
This can involve efforts to maintain hope and to control one’s emotions; it can also involve venting feelings of anger and frustration, or deciding that nothing can be done to change things. For example, tell myself that it is not really happening to me, or worry about what I am going to do.

Avoidance-oriented Strategy:
This involves denying or minimizing the seriousness of the situation; it also involves conscious suppression of stressful thoughts and their replacement by self-protective thoughts. Examples of this are watching TV, phone up a friend, or try to be with other people. Lazarus and Folkman has conceptualized coping as a dynamic process rather than an individual trait. Coping refers to constantly changing cognitive and behavioral efforts to master, reduce or tolerate the internal or external demands that are created by the stressful transaction.

Coping serves to allow the individual to manage or alter a problem and regulate the emotional response to that problem. According to them coping responses can be divided into two types of responses, problem-focused and emotion-focused. Problem-focused -strategies attack the problem itself, with behaviors designed to gain information, to alter the event, and to alter belief and commitments. They increase the person’s awareness, level of knowledge, and range of behavioral and cognitive coping options. They can act to reduce the threat value of the event.

For example “I made a plan of action and followed it”. Emotion-focused strategies call for psychological changes designed primarily to limit the degree of emotional disruption caused by an event, with minimal effort to alter the event itself. For example “I did some things to let it out of my system”. While both problem-focused and emotion-focused coping are necessary when facing stressful situations, research suggests that people generally tend to use the former more often than the latter.

Stress Management Techniques:
Stress is a silent killer. It is estimated to play a significant role in physical illness and disease. Hypertension, heart disease, ulcers, diabetes and even cancer are linked to stress. Due to lifestyle changes stress is on the increase. Therefore, schools, other institutions, offices and communities are concerned about knowing techniques to manage stress. Some of these techniques are.

Relaxation Techniques :
It is an active skill that reduces symptoms of stress and decreases the incidence of illnesses such as high blood pressure and heart disease. Usually, relaxation starts from the lower part of the body and progresses up to the facial muscles in such a way that the whole body is relaxed. Deep breathing is used along with muscle relaxation to calm the mind and relax the body.

Meditation Procedures :
The yogic method of meditation consists of a sequence of learned techniques for refocusing of attention that brings about an altered state of consciousness. It involves such a thorough concentration that the meditator becomes unaware, of any outside stimulation and reaches a different state of consciousness.

Biofeedback :
It is a procedure to monitor and reduce the physiological aspects of stress by providing feedback about current physiological activity and is often accompanied by relaxation training. Biofeedback training involves three stages: developing an awareness of the particular physiological response, e.g. heart rate, learning ways of controlling that physiological response in quiet conditions; and transferring that control into the conditions of everyday life.

Creative Visualisation:
It is an effective technique for dealing with stress. Creative visualization is a subjective experience that uses imagery and imagination. Before visualizing one must set oneself a realistic goal, as it helps build confidence. It is easier to visualize if one’s mind is quiet, body relaxed and eyes are closed. This reduces the risk of interference from unbidden thoughts and provides the creative energy needed for turning an imagined scene into reality.

Cognitive Behavioural Techniques :
These techniques aim to inoculate people against stress. Stress inoculation training is one effective method developed by Meichenbaum. The essence of this approach is to replace negative and irrational thoughts with positive and rational ones.

There are three main phases in this: assessment, stress reduction techniques, and application and follow-through. Assessment involves discussing the nature of the problem and seeing it from the viewpoint of the person/client. Stress reduction involves learning the techniques of reducing stress such as relaxation and self-instruction.

Exercise :
Exercise can provide an active outlet for the physiological arousal experienced in response to stress. Regular exercise improves the efficiency of the heart, enhances the function of the lungs, maintains good circulation, lowers blood pressure, reduces fat in the blood and improves the body’s immune system. Swimming, walking, running, cycling, skipping, etc. help to reduce stress. One must practice these exercises at least four times a week for 30 minutes at a time. Each session must have a warm-up, exercise and cool-down phases.

Question 6.
What is Stress-Resistant Personality?
Answer:
Recent studies by Kobasa have shown that people with high levels of stress but low levels of illness share three characteristics, which are referred to as the personality traits of hardiness. It consists of ‘the three Cs i.e. commitment, control and challenge. Hardiness is a set of beliefs about oneself, the world, and how they interact. It takes shape as a Sense of personal commitment to what you are doing, a sense of control over your life and a feeling of challenge.

Stress-resistant personalities have control which is a sense of purpose and direction in life; commitment to work, family, hobbies and social life and challenge, that is, they see changes in life as normal and positive rather than as a threat. Everyone does not have these characteristics, many of us have to relearn specific life skills in areas such as rational thinking and assertiveness to equip ourselves better to cope with the demands of everyday life, etc.

Life Skills :
Life skills are abilities for adaptive and positive behavior that enable individuals to deal effectively with the demands and challenges of everyday life. Our ability to cope depends on how well we are prepared to deal with and-counterbalance everyday demands and keep equilibrium in our lives. These life skills can be learned and even improved upon. Assertiveness, time management, rational thinking, improving relationships, self-care and overcoming unhelpful habits such as perfectionism, and procrastination, etc. are some life skills that will help to meet the challenges of life.

Assertiveness :
Assertiveness is a behavior or skill that helps to communicate, clearly and confidently, our feelings, needs, wants and thoughts. It is the ability to say no to a request, to state an opinion without being self-conscious, or to express emotions such as love, anger, etc. openly. If you are assertive, you feel confident and have high self-esteem and a solid sense of your own identity.

Time Management:
The way you spend your time determines the quality of your life. Learning how to plan time and delegate can help to relieve the pressure. The major way to reduce time stress is to change one’s perception of time. The central principle of time management is to spend your time doing the things that you value, or that help you to achieve your goals. It depends on being realistic about what you know and that you must do it within a certain time period, knowing what you want to do and organizing your life to achieve a balance between the two.

Rational Thinking :
Many stress-related problems occur as a result of distorted thinking. The way you think and the way you feel are closely connected. When we are stressed, we have an inbuilt selective bias to attend to negative thoughts and images from the past, which affect our perception of the present and the future. Some of the principles of rational thinking are: challenging your distorted thinking and irrational beliefs, driving out potentially intrusive negative anxiety-provoking thoughts and making positive statements.

Improving Relationships:
The key to a sound lasting relationship is communication. This consists of three essential skills: listening to what the other person is saying, expressing how you feel and what you think and accepting the other person’s opinions and feelings, even if they are different from your own. It also requires us to avoid misplaced jealousy and sulking behavior.

Self-care :
If we keep ourselves healthy, fit and relaxed, we are better prepared physically and emotionally to tackle the stresses of everyday life. Our breathing patterns reflect our state of mind and emotions. When we are stressed or anxious, we tend towards rapid and shallow breathing from high in the chest, with frequent sighs. The most relaxed breathing is slow, stomach-centered breathing from the diaphragm, i.e. a dome-like muscle between the chest and the abdominal cavity. Environmental stresses like noise, pollution, space, light, color, etc. can all exert an influence on our mood. These have a noticeable effect on our ability to cope with stress and well-being.

Overcoming Unhelpful Habits:
Unhelpful habits such as perfectionism, avoidance, procrastination, etc. are strategies that help to cope in the short-term but which make one more vulnerable to stress. Perfectionists are persons who have to get everything just right. They have difficulty in varying standards according to factors such as time available, consequences of not being able to stop work, and the effort needed. They are more likely to feel tense and find it difficult to relax, are critical of self and others and may become inclined to avoid challenges.

Avoidance is to put the issue under the carpet and refuse to accept or face it. Procrastination means putting off what we know we need to do. We all are, guilty of saying “I will do it later”. People who procrastinate are deliberately avoiding confronting their fears of failure or rejection. Various factors have been identified which facilitate the development of positive health.

Health is a state of complete physical, mental, social and spiritual well-being and not merely the absence of disease or infirmity. Positive health comprises the following constructs: “a healthy body high quality of personal relationships; a sense of purpose in life; self-regard, mastery of life’s tasks and resilience to stress, trauma, and change”. Box 3.3 presents the relationship between resilience and health. Specifically, factors that act as stress buffers and facilitate positive health are diet, exercise, positive attitude, positive thinking and social support.

Diet:
A balanced diet can lift one’s mood, give more energy, feed muscles, improve circulation, prevent illness, strengthen the immune system and make one feel better to cope with stresses of life. The key to healthy living is to eat three main meals a day and eat a varied well-balanced diet. How much nutrition one needs depends on one’s activity level, genetic makeup, climate and health history. What people eat and how much do they weigh involve behavioral processes. Some people are able to maintain a healthy diet and weight while others become obese. When we are stressed, we seek ‘comfort foods that are high in fats, salt and sugar.

Exercise :
A large number of studies confirm a consistently positive relationship between physical fitness and health. Also, of all the measures an individual can take to improve health, exercise is the lifestyle change with the widest popular approval. Regular exercise plays an important role in managing weight and stress and is shown to have a positive effect on reducing tension, anxiety and depression.Physical exercises that are essential for good health are stretching exercises such as yogic asanas and aerobic exercises such as jogging, swimming, cycling, etc. Whereas stretching exercises have a calming effect, aerobic exercises increase the arousal level of the body. The health benefits of exercise work as a stress buffer. Studies suggest that fitness permits individuals to maintain general mental and physical well-being even in the face of negative life events.

Positive Attitude:
Positive health and well-being can be realized by having a positive attitude. Some of the factors leading to a positive attitude are: having a fairly accurate perception of reality; a sense of purpose in life and responsibility; acceptance and tolerance for different viewpoints of others and taking credit for success and accepting blame for failure. Finally, being open to new ideas and having a sense of humor with the ability to laugh at oneself help us to remain centered Mid see things in a proper perspective.

Positive Thinking:
The power of positive thinking has been increasingly recognized in reducing and coping with stress. Optimism, which is the inclination to expect favorable life outcomes, has been linked to psychological and physical well-being. People differ in the manner in which they cope. For example, optimists tend to assume that adversity can be handled successfully whereas pessimists anticipate disasters. Optimists use more problem-focused coping strategies, and seek advice and help from others. Pessimists ignore the problem or source of stress and use strategies such as giving up the goal with which stress is interfering or denying that stress exists.

Social Support:
Social support is defined as the existence and availability of people on whom we can rely upon, people who let us know that they care about, value and love us. Someone who believes that she/he belongs to a social network of communication and mutual obligation experiences social support. Perceived support, i.e. the quality of social support is positively related to health and well-being. In contrast, social network, i.e. the quantity of social support is unrelated to well-being because it is very time-consuming and demanding to maintain a large social network.

Studies have revealed that women exposed to life event stresses, who had a close friend, were less likely to be depressed and had lesser medical complications during pregnancy. Social support can help to provide protection against stress. People with high levels of social support from family and friends may experience less stress when they confront a stressful experience, and they may cope with it more successfully. Social support may be in the form of tangible support or assistance involving material aid, such as money, goods, services, etc.

For example, a child gives notes to her/his friend, since she/he was absent from school due to sickness. Family and friends also provide informational support about stressful events. For example, a student facing a stressful event such as a difficult board examination, if provided information by a friend who has faced a similar one, would not only be able to identify the exact procedures involved, but also it would facilitate in determining what resources and coping strategies could be useful to successfully pass the examination.

During times of stress, one may experience sadness, anxiety, and loss of self-esteem. Supportive friends and family provide emotional support by reassuring the individual that she/he is loved, valued, and cared for. Research has demonstrated that social support effectively reduces psychological distress such as depression or anxiety, during times of stress. There is growing evidence that social support is positively related to psychological well-being. Generally, social support leads to mental health benefits for both the giver and the receiver.

Question 7.
Effect of noise on Child health.
Answer:
Noise :
Children’s reading abilities, cognitive development, physiological indicators, and motivational tasks are affected by exposure to noise. The most common noises that children are exposed to are transportation (e.g. cars, airplanes), music and other people. Evans’ research reveals significant reading delays for children living near airports and exposed to airport noise. He and his colleagues found these delays in reading to occur alnoise levels far below those required to produce hearing damage or loss.

Chronic and acute noise exposure also affects cognitive development, particularly long-term memory, especially if the task is complex. Short-term memory appears to be less affected, but this is dependent upon volume of noise. One way that children adapt to chronic noise is by disregarding or ignoring auditory input. A consequence of this coping strategy is that children also tune out speech, which is a basic and required component of reading. As a result, not only are children’s reading abilities affected, but also their abilities at tasks that require speech perception.

Noise levels also indirectly influence children’s cognitive development via their effect on the adults and teachers who interact with children. Teachers in noisy schools are more fatigued, annoyed and less patient than teachers in quieter schools. Teachers in noisy schools also losC instruction time due to noise distractions and have a compromised teaching style. Children exposed to chronic loud noise also experience a rise in blood pressure, and stress hormones. And children as young as four are less motivated to perform on challenging language and pre-reading tasks under conditions of exposure to chronic noise.

Question 8.
Short notes :
Answer:
Crowding:
Research demonstrates that crowding has an effect on interpersonal behaviors, mental health, motivation, cognitive development and biological measures. Family size has not been found to be a critical factor in crowding. Rather, Evans identifies density, or number of people per room, as the crucial variable for measuring effects of crowding on children’s development. Regarding child development, Evans has found that 10-12-year-old children are more likely to withdraw in overcrowded situations. Children may engage in withdrawal behavior as a means of coping with an overstimulating environment.

Evans’ research also reveals that a highly concentrated number of children in an activity area results in more distractions and less constructive play among preschool-aged children. Overcrowding also influences parenting behaviors. Parents in crowded homes are less responsive to young children. Evidence of parental unresponsiveness begins early— before a child is one year old and occurs at all income levels. Overcrowding also strains parent-child Relationships. Parents in overcrowded homes are more likely to engage in punitive parenting, which in turn, affects the level of children’s distress.

Evans’ research shows that strained parent-child relationships negatively influence social, emotional and biological measures (e.g. elevated blood pressure) in 10- to 12-year-old children. Children’s mental health status may be affected by overcrowding. Elementary school-aged children who live in more crowded homes display higher levels of psychological distress and they also have higher levels of behavior difficulties in school.Evans has found that overcrowding produces psychological distress among 3rd and 4th-grade students as reported by both the children and their teachers. These effects are intensified if children reside in large, multifamily structures. Effects were also intensified among a group of 8- to 10-year-olds if the family home was chaotic.

Chronic overcrowding influences children’s motivation to perform tasks. Independent of household income, children aged 6-12 show declines in motivational behavior and also demonstrate a level of learned helplessness—a belief that they have no control over their situation and therefore do not attempt to change it—although they have the power to do so. But there are gender differences: Evans found the link between overcrowding and learned helplessness among 10-to- 12-year-olds to exist for girls, but not for boys.

Evans’ studies find several effects of overcrowding on both objective and subjective measures of children’s cognitive development. Elementary school children living in more crowded homes score lower on standardized reading tests and they see themselves as less scholastically competent than their classmates.  Parenting behaviors directly related to children’s cognitive and language development are also affected by density level.Evans found that parents in crowded homes speak less to their infants and rise fewer complicated words during the period from infancy up to age two and a half. Research demonstrates that the quality and sophistication of speech as well as the quantity of words spoken by parents to their children are significant factors in the amount and types of words children produce.

Biological measures implicate the effects of overcrowding on children’s physiology. In one study, Evans found gender differences in measures of blood pressure among 10-12- year-old children with males in higher residential crowding situations demonstrating elevations in blood pressure, but not females. However, higher overnight levels of the stress hormones epinephrine and norepinephrine were found in both 8- to 10-year-old male and female children living in high-density apartments. This finding was especially relevant when chaos and disorder was present in the family.

Housing and Quality of Neighborhood:
Housing quality and the neighborhoods in which houses are situated have also been investigated in relation to children’s socio-emotional development. For example, families living in high-rise housing, as opposed to single-family residences, have fewer relationships with neighbors, resulting in less social support. Studies on housing and the quality of neighborhoods have also examined the role of chaos in children’s environments finding an association between chaotic home environments and levels of psychological distress among middle school children.

Research has identified the physical characteristics of neighborhoods that significantly influence children’s development. These characteristics include residential instability, housing quality, noise, crowding, toxic exposure, quality of municipal services, retail services, recreational opportunities, including natural settings, street traffic, accessibility of transportation and the physical quality of both educational and health facilities. Perhaps not surprisingly, Evans’ research findings support the therapeutic effects of children’s exposure to natural settings.

Natural settings are preferred by children and allow them to exercise gross motor abilities as well as engage in social interactions. In addition, these settings also alleviate the adverse effects of children’s exposure to chronic stress. The research outlined above demonstrates both the direct and indirect effects of the physical environment on children’s development. Direct effects include cognitive, social, emotional and biological outcomes.Indirect effects include interactions with parents and teachers, which in turn, influence developmental outcomes such as learning and language development.

Although in several studies Evans demonstrates these effects for children at all income levels, low-income children experience excessive exposure to noise, overcrowding and unfavorable housing and neighborhood conditions.Exposure to these poor-quality physical conditions is linked to other psychological and social aspects of the environment, especially poverty. Using a building block analogy, low-income children have more blocks stacked one on top of the other than children of other income levels. Thus, children living in poverty experience multiple exposures, rather than a single exposure to risk.

What You Can Do to check the impact of the environment on human behavior?

Guard against additional, interior noise sources:
Individuals living in noisy environments often habituate or become accustomed to the noise level. Aim to reduce the existing noise instead of adding other sources of noise. Check the volume level on your child’s music devices (e g., iPod, Walkman; it is too loud if someone else can hear the music). If he listens to his favorite music too loudly, make proper volume adjustments. Also monitor the volume level on computers, televisions, and other electronic devices, keeping them as low as possible.

Engage your child:
Children ignore and tune out speech as a way of coping with environmental overstimulation. Take notice if your child is not paying attention or listening to your speech and if so, intervene. Take your child to a quiet outdoor nature spot or a quiet indoor location such as the local library) This is especially important during the preschool and early elementary school years (ages 3-6 years) when children are learning to read.

Tune in instead of tuning out:
Parents living under high noise exposure appear to withdraw, be less responsive and talk less to their children. The natural tendency is to disengage from speaking and reading to children so as not to compete with the noise. These coping strategies negatively affect children’s reading and cognitive abilities. Be alert to the occurrence of these behaviors and counter them by talking to your child, reading aloud to her, engaging her in discussions, and actively listening to what she has to say to you.

Modify your environment:
If your budget permits, consider purchasing extra noise attenuation devices for your child’s room for use during homework activities and sleeping. Earplugs are a low-cost alternative.

Consider your child’s school environment:
If you have a choice, send your child to a quiet, less chaotic school. This is particularly desirable if your home environment is also noisy. Be active in your community. The noisiest environmental conditions occur in low-income and ethnic minority communities. One way to counteract this is to be active and involved. Ask your representative why it is noisier, in these communities.

Seek information:
If a major source of noise in your community is road traffic, check with your local planning department. Note that traffic volume is closely aligned with traffic noise levels. The busiest streets are usually the noisiest.

Examination Anxiety:
Examination anxiety is a fairly common phenomenon that involves feelings of tension or uneasiness that occur before, during, or after an examination. Many people experience feelings of anxiety around, examinations and find it helpful in some ways, as it can be motivating and create the pressure that is needed to stay focused on one’s performance. Examination nerves, worry, or fear of failure are normal for even the most talented student. However, the stress of formal examination results in such high degrees of anxiety in some students that they are unable to perform at a level that matches the potential they have shown in less stressful classroom situations.

Examination stress has been characterized as “evaluative apprehension” or “evaluative stress” and produces debilitating behavioral, cognitive and physiological effects no different from those produced by any other stressor. High stress can interfere with the student’s preparation, concentration and performance. Examination stress can cause test anxiety which adversely affects test performance. Persons who are high in test anxiety tend to perceive evaluative situations as personally threatening; in test situations, they are often tense, apprehensive, nervous and emotionally aroused.Moreover, the negative self-centered cognitions which they experience distract their attention and interfere with concentration during examinations.

High-test anxious students respond to examination stress with intense emotional reactions, negative thoughts about themselves, feelings of inadequacy, helplessness and loss of status and esteem that impair their performance. Generally, the high-test anxious person instead of plunging into a task plunges inward, that is, either neglect or misinterprets informational cues that may be readily available to her/him, or experiences attentional blocks.While preparing for examinations, one must spend enough time for study, overviewing and weighing one’s strengths and weaknesses, discuss difficulties with teachers and classmates, plan a revision timetable, condensing notes, space out revision periods and most importantly on the examination day concentrate on staying palm.

Question 9.
What do you understand by the term ‘environment’? Explain the different perspectives to understand the human-environment relationship.
Answer:
‘Environment’ refers to all that is around us. Literally, it means everything that surrounds us including the physical, Social world and cultural environment. In general, it includes all the forces outside the human beings to which they respond in Some way. There is more than one way of looking at the human-environment relationship.
A psychologist named Stokols (1990) describes three approaches that may be adopted to describe the human-environment relationship.

• The minimalist perspective assumes that the physical environment has minimal or negligible influence on human behavior, health and well-being. The physical environment and human beings exist as parallel components.
• The instrumental perspective suggests that the physical environment exists mainly for use by human beings for their comfort and well-being. Most of the human influences on the environment reflect the instrumental perspective.
• The spiritual perspective refers to the view of the environment as. something to be respected and valued rather than exploited. It implies that human beings recognize the interdependent relationship between themselves and the environment, i.e. human beings will exist and will be happy only as long as the environment is kept healthy and natural.
  The traditional Indian view about the environment supports the spiritual perspective.

Question 10.
“Human beings affect and are affected by the environment”. Explain this statement with the help of examples.
Answer:
Human beings exert their influence on the natural environment for fulfilling their physical needs and other purposes. The human-environment relationship can be appreciated fully by understanding that the two influence each other and depend on each other for their survival and maintenance. Some aspects of the environment influence human perception.

• Environmental influences on perception :
  Some aspects of the environment influence human perception. For example, a tribal society of Africa lives in circular huts, that is, in houses without angular walls. They show less error in a geometric illusion (the Muller-Lyer illusion) than people from cities, who live in houses with angular walls.
• Environmental influences on emotions:
  The environment affects our emotional reactions as well. Watching nature iri any form, whether it is a quietly flowing river, a smiling flower, or a tranquil mountain top, provides a kind of joy that cannot be matched by any other experience. Natural disasters, such as floods, droughts, landslides, and quakes on the earth or under the ocean, can affect people’s emotions to such an extent that they experience deep depression and sorrow, a sense of complete helplessness and lack of control over their lives.
• Ecological influences on occupation, living style, and attitudes :
  The natural environment of a particular region determines whether people living in that region rely on agriculture (as in the plains), or on other occupations such as hunting and gathering (as in a forest, mountainous or desert regions), or on industries (as in areas that are not fertile enough for agriculture). In turn, occupation determines the lifestyle and attitudes of the residents of a particular geographical region.

Question 11.
What is noise? Discuss the effects of noise on human behavior.
Answer:
Any sound that is annoying or irritating and felt to be unpleasant is said to be noise. From common experience, it is known that noise, especially for long periods of time, is uncomfortable and puts people in an unpleasant mood.

Effects of noise on human behavior:

• When the task being performed is a simple mental task, such as the addition of numbers, noise does not affect overall performance, whether it is loud or soft.
  In such situations, people adapt, or ‘get used to noise.
• If the task being performed is very interesting, then, too, the presence of noise does not affect performance. This is because the nature of the task helps the individual to pay full attention to the task and ignore the noise. This may also be one kind of adaptation.
• When the noise comes at intervals, and in an unpredictable way, it is experienced as more disturbing than if the noise is continuously present.
• When the task being performed is difficult or requires full concentration, then intense, unpredictable and uncontrollable noise reduces the level of task performance.
• When tolerating or switching off the noise is within the control of the person, the number of errors in task performance decreases.
• In terms of emotional effects, noise above a certain level causes annoyance, and can also lead to sleep disturbance. These effects are also reduced if the noise is controllable, or is necessary as a part of the person’s occupation. However, continued exposure to uncontrollable and annoying noise can have harmful effects on mental health.

Question 12.
What are the salient features of crowding? Explain the major psychological consequences of crowding.
Answer:
Crowding to a feeling of discomfort because there are too many people or things around us, giving us the experience of physical restriction and sometimes the lack of privacy. Crowding is the person’s reaction to the presence of a large number of persons within a particular area or space. When this number goes beyond a certain level, it causes stress to individuals caught in that situation. In this sense, crowding is another example of an environmental stressor.

The experience of crowding has the following features :

• Feeling of discomfort,
• Loss or decrease in privacy,
• Negative view of the space around the person, and
• The feeling of loss of control over social interaction.

1. Crowding and high density may lead to abnormal behavior and aggression. This was shown many years ago in a study of rats. These animals were placed in an enclosure, initially in small numbers. As their population increased within this enclosed space, they started showing aggressive and unusual behavior, such as biting the tails of other rats. This aggressive behavior increased to such an extent that ultimately the animals died in large numbers, thus decreasing the population in the enclosure. Among human beings also, an increase in population has sometimes been found to be accompanied by an increase in violent crime.
2. Crowding leads to lowered performance on difficult tasks that involve cognitive processes and has adverse effects on memory and the emotional state. These negative effects are seen to a smaller extent in people who are used to crowded surroundings.
3. Children growing up in very crowded households show lower academic performance. They also show a weaker tendency to continue working on a task if they are unsuccessful at it, compared to children growing up in non-crowded households. They experience greater conflict with their parents and get less support from their family members.

Question 13.
Why is the concept of ‘personal space’ important for human beings? Justify your answer with the help of an example.
Answer:
Personal space or the comfortable physical space one generally likes to maintain around oneself, is affected by a high-density environment. In a crowded context, there is a restriction on personal space and this can also be a cause of negative reactions to crowding.

For example: In social situations, human beings like to maintain a certain physical distance from die person with whom they are interacting. This is called interpersonal al physical distance and is a part of a broader concept called personal space, i.e. the physical space we like to have all around us. One reason for the negative reactions to crowding, as described earlier, is the decrease in personal space.

Odisha State Board Elements of Mathematics Class 12 CHSE Odisha Solutions Chapter 7 Continuity and Differentiability Ex 7(d) Textbook Exercise Questions and Answers.

CHSE Odisha Class 12 Math Solutions Chapter 7 Continuity and Differentiability Exercise 7(d)

Question 1.
Prove the formulae (4) to (7).
Solution:
(4) \(\frac{d}{d x}\)(cos-1 x) = \(\frac{-1}{\sqrt{1-x^2}}\)
Let y = cos^-1 x
⇒ x = cos y
⇒ \(\frac{d}{d x}\) = \(\frac{1}{\left(\frac{d x}{d y}\right)}\) = \(\frac{1}{-\sin y}\)
But sin y ≥ 0 when
y ∈ [0, π] ( ∵ [0, π] is the principal value branch for cos^-1 x)
∴ \(\frac{d y}{d x}\) = \(\frac{-1}{\sqrt{1-\cos ^2 y}}\) = \(\frac{-1}{\sqrt{1-x^2}}\)

(5) Let y = tan^-1 x
⇒ x = tan y

(6) Let y = cot^-1 x
⇒ x = cot y

(7) Let y = cosec^-1 x
⇒ x = cosec y

Question 2.
Find derivatives of the following functions.
sin^-1 2x
Solution:
y = sin^-1 2x

Question 3.
cot^-1 √x
Solution:
cot^-1 √x

Question 4.
sec^-1 (2x + 1)
Solution:
y = sec^-1 (2x + 1)

Question 5.
cos^-1 \(\sqrt{\frac{1+x}{2}}\)
Solution:

Question 6.
cos^-1 \(\left(\frac{x-\frac{1}{x}}{x+\frac{1}{x}}\right)\)
Solution:

Question 7.
tan^-1 (cos √x)
Solution:
y = tan^-1 (cos √x)

Question 8.
x² cosec^-1 \(\left(\frac{1}{\ln x}\right)\)
Solution:

Question 9.
cot^-1 \( \frac{\sqrt{1-x^2}}{x} \)
Solution:

Question 10.
(x sin^-1 x)¹⁵
Solution:
y = (x sin^-1 x)¹⁵

Question 11.
sin^-1 \( \sqrt{\frac{1-x}{1+x}} \)
Solution:

Odisha State Board Elements of Mathematics Class 12 CHSE Odisha Solutions Chapter 1 Relation and Function Ex 1(c) Textbook Exercise Questions and Answers.

CHSE Odisha Class 12 Math Solutions Chapter 1 Relation and Function Exercise 1(c)

Question 1.
Show that the operation ∗ given by x ∗ y = x + y – xy is a binary operation on Z, Q and R but not on N.
Solution:
The operation ∗ given by
x ∗ y = x + y – xy
Clearly for all x, y ∈ Z
x + y – xy ∈ Z
⇒ x ∗ y ∈ Z
∴ ∗ is a binary operation on Z.
For all x, y ∈ Q
x + y – xy ∈ Q
⇒ x ∗ y ∈ Q
⇒ ∗ is a binary operation on Q for all x, y, ∈ R.
x + y – xy ∈ R
⇒ x ∗ y ∈ R
⇒ ∗ is a binary operation on R
Again 3, 4 ∈ N.
3 + 4 – 3 x 4 = 7 – 12 = – 5 ∉ N
i.e., x, y ∈ N
≠ x ∗ y ∈ N
∴ ∗ is not a binary operation on N.

Question 2.
Determine whether the following operations as defined by ∗ are binary operations on the sets specified in each case. Give reasons if it is not a binary operation.
(i) a ∗ b = 2a + 3b on Z.
(ii) a ∗ b = ma – nb on Q⁺ where m and n ∈ N.
(iii) a ∗ b = a + b (mod 7) on {0, 1, 2, 3, 4, 5, 6}
(iv) a ∗ b = min {a, b} on N.
(v) a ∗ b = GCD {a, b} on N.
(vi) a ∗ b = LCM {a, b} on N.
(vii) a ∗ b = LCM {a, b} on {0, 1, 2, 3, 4……, 10}
(viii) a ∗ b = \(\sqrt{a^2+b^2}\) on Q⁺
(ix) a ∗ b =a × b (mod 5) on {0, 1, 2, 3, 4}.
(x) a ∗ b = a² + b² on N.
(xi) a ∗ b = a + b – ab on R – {1}.
Solution:
(i) For all a, b ∈ Z
2a + 3b ∈ Z
⇒ a ∗ b ∈ Z
∗ is a binary operation on Z.

(ii) Let a = 1, b = 2
m = 1, n = 3
ma – nb = 1 – 6 = – 5 ∉ Q⁺
∴ a, b ∈ Q⁺ ≠ a ∗ b ∈ Q⁺
⇒ ∗ is not a binary operation on Q⁺

(iii) a ∗ b = a + b (mod 7) ∈ {0, 1, 2, 3, 4, 5, 6}
for a, b ∈ 7
∗ is a binary operation on the given set.

(iv) a, b ∈ N ⇒ min {a, b} ∈ N
∴ a ∗ b ∈ N
⇒ ∗ is a binary operation on N.

(v) for all a, b ∈ N, GCD [a, b] ∈ N
⇒ a ∗ b ∈ N
⇒ ∗ is a binary operation on N.

(vi) for all a, b ∈ N, LCM {a, b} ∈ N
⇒ a ∗ b ∈ N
⇒ ∗ is a binary operation on N.

(vii) Let A = {0, 1, 2, ….. 10}
4, 5 ∈ A but 4 ∗ 5 = LCM {4, 5}
= 20 ∉ A
⇒ ∗ is not a binary operation on A.

(viii) for all a, b ∈ Q⁺
a ∗ b = \(\sqrt{a^2+b^2}\) ∉ Q⁺
⇒ ∗ is not a binary operation on Q⁺.

(ix) For all a, b ∈ {0, 1, 2, 3, 4}
a ∗ b = a × b (mod 5) ∈ {0, 1, 2, 3, 4}
∴ ∗ is a binary operation on the given set.

(x) for all a, b ∈ N, a * b = a² + b² ∈ N
∴ ∗ is a binary operation on N.

(xi) For all a, b ∈ R – {1}
a ∗ b = a + b – ab ∈ R – {1}
∴ ∗ is a binary operation on R – {1}

Question 3.
In case ∗ is a binary operation in Q2 above, test whether it is (i) associative
(ii) commutative, Test further if the identity element exists and the inverse element for any element of the respective set exists.
Solution:
(i) On Z the binary operation is
a ∗ b = 2a + 3b
Commutative:
b ∗ a = 2b + 3a ≠ a ∗ b
∴ ∗ is not commutative.

Associative:
(a ∗ b) ∗ c = (2a + 3b) ∗ c
= 2 (2a + 3b) + 3c
= 4a + 6b + 3c
a ∗ (b ∗ c) = a ∗ (2b + 3c)
= 2a + 3 (2b + 3c)
= 2a + 6b + 9c
As (a ∗ b) ∗ c ≠ a ∗ (b ∗ c)
∗ is not associative.

Existance of identity:
Let e is the identity
∴ e ∗ a = a
⇒ 2e + 3a = a
⇒ e = -2a / 2 = -a
which depends on a.
∴ Identity element does not exist.

(iii) A = (0, 1, 2, 3, 4, 5, 6}
Commutative:
a ∗ b = a + b (mod 7)
= The remainder obtained when a + b is divided by 7.
b ∗ a = b + a (mod 7) = a + b (mod 7)
∴ ∗ is commutative.

Associative:
(a ∗ b) ∗ c = {a + b (mod 7)} ∗ c
= a + b + c (mod 7)
= The remainder obtained if a + b + c is divided by 7.
a ∗ (b ∗ c) = a ∗ {b + c (mod 7)}
= a + b + c (mod 7)
= The remainder obtained if a + b + c is divided by 7.
∴ (a ∗ b) ∗ c = a + (b ∗ c)
∴ ∗ is associative.

Existance of identity:
Let e is the identity
⇒ e ∗ a = a ∗ e = a
⇒ e + a mod 7 = a
⇒ e = 0
∴ 0 is the identity.

Existance of inverse:
Let a^-1 = the inverse of a
⇒ a ∗ a^-1 = a^-1 ∗ a = e = 0
⇒ a + a^-1 (mod 7) = 0
⇒ a + a^-1 is divisible by 7.
1^-1 = 6, 6^-1 = 1
2^-1 = 5, 5^-1 = 2
3^-1 = 4, 4^-1 = 3

(iv) a ∗ b = min {a, b} on N.
Commutative:
a ∗ b = min {a, b}
b ∗ a – min {b, a} = a ∗ b
∴ ∗ is commutative.
Associative:
(a ∗ b) ∗ c = min {a, b} ∗ c
= min {a, b, c}
a ∗ (b ∗ c)= a ∗ min {b, c}
= min {a, b, c}
⇒ a ∗ (b ∗ c) = (a ∗ b) ∗ c
∴ ∗ is associative.

Existance of Identity:
Let e is the identity
∴ For all a ∈ N
e ∗ a = a ∗ e = a
⇒ min {e, a} = a
No such element exists in N.
∴ ∗ has no identity element on N.

(v) a ∗ b = GCD {a, b} on N.
b ∗ a = GCD {b, a} = GCD {a, b} = a ∗ b
∴ ∗ is commutative.
Associative:
(a ∗ b) ∗ c = GCD {a, b} ∗ c
= GCD {a, b, c}
a ∗ (b ∗ c) = a ∗ GCD {b, c}
= GCD {a, b, c}
⇒ (a ∗ b) ∗ c = a ∗ (b ∗ c)
⇒ ∗ is associative.

Existance of Identity:
Let e is the identity
∴ a ∗ e = e ∗ a = a
⇒ GCD {e, a} = a
No such element exists in N
⇒ ∗ has no indentity element.

(vi) a ∗ b = LCM {a, b} on N
Commutative:
a ∗ b = LCM {a, b}
= LCM {b, a}
= b ∗ a
∴ ∗ is commutative.

Associative
(a ∗ b) ∗ c = LCM {a, b} ∗ c
= LCM {a, b, c}
a ∗ (b ∗ c) =» a ∗ LCM {b, c}
= LCM {a, b, c}
⇒ (a ∗ b) ∗ c = a ∗ (b ∗ c)
∴ ∗ is associative.

Existance of Identity:
Let e is the identity
∴ e ∗ a = a ∗ e = a
⇒ LCM {e, a} = a
⇒ e – 1
∴ 1 is the identity element.

Existance of inverse:
Let a^-1 is the inverse of a
⇒ a * a^-1 = e = 1
⇒ LCM [a, a^-1} = 1
a = a^-1 = 1
Only 1 is invertible with 1^-1 = 1.

(ix) a ∗ b = a × (mod 5) on {0, 1, 2, 3, 4}

Commutative:
a ∗ b = a x b (mod 5)
= Remainder on dividing a x b by 5
= Remainder on dividing b x a by 5
= b x a (mod 5)
= b x a
∴ ∗ is commutative.

Associative:
(a ∗ b) ∗ c=a x b (mod 5) ∗ c
= a x b x c (mod 5)
a and a ∗ {b ∗ c} = a ∗ {b x c (mod 5)}
= a x b x c (mod 5)
∴ (a ∗ b) ∗ c -=a ∗ (b ∗ c)
⇒ ∗ is associative.

Existance of identity:
Let e is the identity
∴ For all a ∈ {0, 1, 2, 3, 4}
a ∗ a = e ∗ a = a
a × e (mod 5) = a
⇒ e = 1
∴ 1 is the identity element.

Existance of inverse:
Let a^-1 is the inverse of a
∴ a ∗ a^-1= a^-1 ∗ a = e = 1
⇒ a x a^-1 (mod 5) = 1
⇒ 1^-1 = 1
2^-1 = 3, 3^-1 = 2, 4^-1 = 4
0 has no inverse.

(x) a ∗ b = a² + b² on N.
Commutative:
a ∗ b = a² + b²
b ∗ a = b² + a² = a² + b² = a ∗ b
∴ ∗ is commutative.

Associative:
(a ∗ b) ∗ c = (a² + b²) ∗ c
= (a² + b²)² + c²
a ∗ (b ∗ c) = a ∗ (b² + c²)
= a² + (a² + b²)²
(a ∗ b) ∗ c ≠ a ∗ (b ∗ c)
∴ ∗ is not associative.

Existance of Identity:
Let e is the identity
a ∗ e = e ∗ a = a
⇒ a² + e² = a
⇒ e = \( \sqrt{a-a^2}\) which depends on a
∴ Identity does not exist.

(xi) a ∗ b = a + b – ab on R – {1}
Commutative:
a ∗ b = a + b – ab
b ∗ a = b + a – ba
a ∗ b = b ∗ a
∴ ∗ is commutative.

Associative:
a ∗ (b ∗ c) = a ∗ (b + c – bc)
= a + (b + c – bc) – a (b + c – bc)
= a + b + c – bc – ab – ac + abc
(a ∗ b) ∗ c = (a + b – ab) ∗ c
= a + b – ab + c – (a + b – ab) c
= a + b + c – ab – bc – ca + abc
∴ (a ∗ b) ∗ c = a ∗ (b ∗ c)
⇒ ∗ is associative.

Existance of Identity:
Let e is the identity
∴ e ∗ a = a ∗ e = a
⇒ a + e – ae = a
⇒ e (1 – a) = 0
⇒ e = 0 (∵ a ≠ 1)
∴ 0 is the identity.

Existance of inverse:
Let a^-1 is the inverse of a
⇒ a ∗ a^-1 = a^-1 ∗ a = e
⇒ a + a^-1 – aa^-1 = 0
⇒ a^-1 (1 – a) = – a
⇒ a^-1 = \(\frac{a}{a-1}\) for a ∈ R – {1}

Question 4.
Construct the composition table/multiplication table for the binary operation ∗ defined on {0, 1, 2, 3, 4} by a ∗ b = a × b {mod 5). Find the identity element if any. Also find the inverse elements of 2 and 4.
[This operation is called multiplication moduls 5 and denoted by x⁵. In general, on a finite subset of N, x_m denotes the operation of multiplication modulo m where m is a fixed positive integer].
Solution:
A = {0. 1, 2, 3, 4}
a ∗ b = a × b mod 5

∗	0	1	2	3	4
0	0	0	0	0	0
1	0	1	2	3	4
2	0	2	4	1	3
3	0	3	1	4	2
4	0	4	3	2	1

As 3rd row is identical to the first row we have 1 is the identity clearly 2^-1 = 3 and 4^-1 = 4.

Odisha State Board Elements of Mathematics Class 12 CHSE Odisha Solutions Chapter 7 Continuity and Differentiability Ex 7(e) Textbook Exercise Questions and Answers.

CHSE Odisha Class 12 Math Solutions Chapter 7 Continuity and Differentiability Exercise 7(e)

Differentiate the following functions by proper substitution.
Question 1.
sin^-1 2x\( \sqrt{1-x^2} \)
Solution:
y = sin^-1 2x\( \sqrt{1-x^2} \)   [Put x = sin θ
= sin^-1 (2 sin θ . cos θ)
= sin^-1 sin 2θ = 2θ = 2 sin^-1 x.
\(\frac{d y}{d x}\) = \(\frac{2}{\sqrt{1-x^2}}\)

Question 2.
tan^-1 \(\frac{2 x}{1-x^2}\)
Solution:
y = tan^-1 \(\frac{2 x}{1-x^2}\)
= tan^-1 \(\frac{2 \tan \theta}{1-\tan ^2 \theta}\) = tan^-1 (tan 2θ)
= 2θ = 2 tan^-1 x
∴ \(\frac{d y}{d x}\) = \(\frac{2 x}{1-x^2}\)

Question 3.
tan^-1 \(\sqrt{\frac{1-t}{1+t}}\)
Solution:

Question 4.
\(\left[\left(\frac{1+t^2}{1-t^2}\right)^2-1\right]^{\frac{1}{2}}\)
Solution:

Question 5.
tan^-1 \(\left(\frac{\sqrt{x}+\sqrt{a}}{1-\sqrt{x a}}\right)\)
Solution:

Question 6.
sin^-1 (\(\frac{2 x}{1+x^2}\))
Solution:
y = sin^-1 \(\frac{2 x}{1+x^2}\)  [Put x = tan θ
= sin^-1 \(\frac{2 \tan \theta}{1+\tan ^2 \theta}\) = sin^-1 sin θ
= 2θ = 2 tan^-1 x
∴ \(\frac{d y}{d x}\) = \(\frac{2 x}{1+x^2}\)

Question 7.
sec^-1 \(\left(\frac{\sqrt{a^2+x^2}}{a}\right)\)
Solution:

Question 8.
sin^-1 \(\left(\frac{2 \sqrt{t^2-1}}{t^2}\right)\)
Solution:

Question 9.
cos^-1 \(\left(\frac{1-t^2}{1+t^2}\right)\)
Solution:
y = cos^-1 \(\left(\frac{1-t^2}{1+t^2}\right)\) [Put t = tan θ
= cos^-1 \(\frac{1-\tan ^2 \theta}{1+\tan ^2 \theta}\)
= cos^-1 cos 2θ = 2 tan^-1 t
∴ \(\frac{d y}{d x}\) = \(\frac{2}{1+t^2}\)

Question 10.
cos^-1 (2t² – 1)
Solution:
y = cos^-1 (2t² – 1) [Put t = tan θ
= cos^-1 (2 cos² θ – 1)
= cos^-1 cos 2θ = 2θ = 2 cos^-1 t
∴ \(\frac{d y}{d x}\) = – \(\frac{2}{\sqrt{1-t^2}}\)

Odisha State Board Elements of Mathematics Class 12 CHSE Odisha Solutions Chapter 7 Continuity and Differentiability Ex 7(f) Textbook Exercise Questions and Answers.

CHSE Odisha Class 12 Math Solutions Chapter 7 Continuity and Differentiability Exercise 7(f)

Find derivatives of the following functions.
Question 1.
x^x
Solution:
Let y = x^x
Then In y = x . In x
⇒ \(\frac{d}{d x}\)(In y) = \(\frac{d}{d x}\)(x . In x)
⇒ \(\frac{1}{y}\)\(\frac{d y}{d x}\) = In x + x . \(\frac{1}{x}\) = In x + 1 = 1 + In x
⇒ \(\frac{d y}{d x}\) = y (1 + In x) = x^x (1 + In x) = x^x In (ex)

Question 2.
\(\left(1+\frac{1}{x}\right)^x\)
Solution:

Question 3.
x^{sin x}
Solution:
y = x^{sin x}
⇒ In y = sin x . In x
⇒ \(\frac{1}{y}\)\(\frac{d y}{d x}\) = cos x In x + sin x . \(\frac{1}{x}\)
⇒ \(\frac{d y}{d x}\) = x^{sin x} (cos x . In x + \(\frac{\sin x}{x}\))

Question 4.
(log x)^{tan x}
Solution:
y = (log x)^{tan x}
⇒ log y = tan x . log (log x)
⇒ \(\frac{1}{y}\)\(\frac{d y}{d x}\) = sec² x log (log x) + tan x . \(\frac{1}{\log x}\) . \(\frac{1}{x}\)
⇒ \(\frac{d y}{d x}\) = (log x)^{tan x} {sec² x . log log x + \(\frac{\tan x}{x \log x}\)}

Question 5.
\(2^{\left(2^x\right)}\)
Solution:
y = \(2^{\left(2^x\right)}\)
⇒ In y = 2^x . In 2
⇒ \(\frac{1}{y}\)\(\frac{d y}{d x}\) = 2^x . In 2 . In 2
⇒ \(\frac{d y}{d x}\) = \(2^{\left(2^x\right)}\) . 2^x . (In 2)²

Question 6.
\((1+\sqrt{x})^{x^2}\)
Solution:

Question 7.
\(\left(\sin ^{-1} x\right)^{\sqrt{1-x^2}}\)
Solution:

Question 8.
\((\tan x)^{\log x^3}\)
Solution:

Question 9.
x^1/x + (sin x)^x
Solution:

Question 10.
(cos x)^x + x^{cos x}
Solution:

Question 11.
(x² + 1)^2/3 (3x + 1)^1/4 √x
Solution:

Question 12.
\(\frac{(x+1)(x+2)^2(x+3)^3}{(x-1)(x-2)^2(x-3)^3}\)
Solution:

Question 13.
(sin x)^x \(\sqrt{\sin x}\left(1+x^2\right)^{\frac{1}{2}+x}\)
Solution:

Question 14.
(sec x + tan x)^{cot x}
Solution:
y = (sec x + tan x)^{cot x}
⇒ In y = cot x . In (sec x + tan x)
⇒ \(\frac{1}{y}\)\(\frac{d y}{d x}\) = -cosec² x . In (sec x + tan x) + cot x . \(\frac{1}{\sec x+\tan x}\) × (sec x . tan x + sec² x)
= -cosec² x . In (sec x + tan x) + cot x . sec x
∴ \(\frac{d y}{d x}\) = y {-cosec² x . In (sec x + tan x) + cosec x}
= (sec x + tan x)^{cot x} {cosec x – cosec² x . In (sec x + tan x)}

Question 15.
(2^√x)^1+√x
Solution:

Odisha State Board CHSE Odisha Class 12 Biology Important Questions Chapter 17 Environmental Issues Important Questions and Answers.

CHSE Odisha 12th Class Biology Important Questions Chapter 17 Environmental Issues

Environmental Issues Class 12 Important Questions CHSE Odisha

Very Short Answer Type Questions

Choose the correct option

Question 1.
The major pollutant from automobile exhaust is known as
(a) NO
(b) CO
(c) SO₂
(d) Soot
Answer:
(b) CO

Question 2.
Which air pollutant could cause rains to be acidic?
(a) Dust particles from cement factories
(b) Insecticides from crop sprays
(c) Smoke from wood fires
(d) Sulphur dioxide from coat-fired power stations
Answer:
(d) Sulphur dioxide from coat-fired power stations

Question 3.
Which process does not result in the return of carbon dioxide to the atmosphere?
(a) Combustion of fossil fuels
(b) Decomposition of humus
(c) Respiration by bacteria
(d) Photosynthesis by green plants
Answer:
(d) Photosynthesis by green plants

Question 4.
Which kind of power station produces sulphur dioxide causing air pollution and acid rain?
(a) Loal-fired
(b) Nuclear
(c) Hydroelectric
(d) Wind-powered
Answer:
(a) Loal-fired

Question 5.
Eutrophication in lakes is the direct result of
(a) a diminished supply of nitrates and phosphates
(b) industrial poisons
(c) nutrient enrichment such as nitrate and phosphate runoffs from the land
(d) an increase in predators
Answer:
(c) nutrient enrichment such as nitrate and phosphate runoffs from the land

Question 6.
Why does the oxygen concentration in the water decrease when sewage is discharged into a river?
(a) Decrease in the number of plants
(b) Increase in the number of fish
(c) Less oxygen absorbed from the air
(d) Rapid growth of bacteria
Answer:
(d) Rapid growth of bacteria

Question 7.
Minamata disease is due to pollution of water by
(a) mercury
(b) lead
(c) tin
(d) methylisocyanate
Answer:
(a) mercury

Question 8.
The effects of radioactive pollutants depend upon
(a) the rate of diffusion
(b) energy releasing capacity
(c) rate of deposition of contaminant
(d) All of the above
Answer:
(d) All of the above

Question 9.
The most harmful types of environment pollutants are
(a) human organic wastes
(b) wastes from faecal
(c) non-biodegradable chemicals
(d) natural nutrients present in excess
Answer:
(c) non-biodegradable chemicals

Question 10.
Taj Mahal is threatened to ……….. the effect of
(a) chlorine
(b) SO₂
(c) oxygen
(d) hydrogen
Answer:
(b) SO₂

Question 11.
CO is a pollutant because it
(a) inactivates nerves
(b) combines with oxygen
(c) combines with Hb
(d) inhibits growth
Answer:
(c) combines with Hb

Question 12.
Flyash is an environmental pollutant produced by
(a) thermal power plant
(b) oil refinery
(c) fertilisation plant
(d) strip mining
Answer:
(d) strip mining

Question 13.
Which type of pollution is caused by scooters?
(a) Air pollution
(b) Soil pollution
(c) Both (a) and (b)
(d) Water pollution
Answer:
(a) Air pollution

Question 14.
Acid rain occurs in areas where
(a) large plantation occurs
(b) small plantation occurs
(c) there are big industries and the atmosphere is polluted with SO₂
(d) there are no industries
Answer:
(c) there are big industries and the atmosphere is polluted with SO₂

Question 15.
Air pollution effects are usually found on the
(a) leaves
(b) flowers
(c) stems
(d) roots
Answer:
(a) leaves

Question 16.
Eutrophic lakes are highly
(a) productive
(b) enriched with phosphates
(c) heavy metal
(d) None of the above
Answer:
(b) enriched with phosphates

Question 17.
Global warming can be controlled by
(a) reducing reforestation, increasing the use of fossil fuel
(b) increasing deforestation, slowing down the growth of human population
(c) increasing deforestation, reducing efficiency of energy usage
(d) reducing deforestation, cutting down use of fossil fuel
Answer:
(d) reducing deforestation, cutting down use of fossil fuel

Question 18.
The common refrigerant that is responsible for the depletion of stratospheric ozone is
(a) CFC
(b) NO
(c) SO₂
(d) Ozone
Answer:
(a) CFC

Question 19.
Slash and burn agriculture is known as
(a) striping farming
(b) intercrop farming
(c) jhum cultivation
(d) intensive farming
Answer:
(c) jhum cultivation

Question 20.
Ozone hole is the
(a) absence of O₃ in stratosphere
(b) presence of O₃ in stratosphere
(c) deficiency of O₃ in stratosphere
(d) deficiency of O₃ in stratosphere
Answer:
(c) deficiency of O₃ in stratosphere

Question 21.
Ozone depletion is occurring due to
(a) PCB
(b) CO
(c) PAN
(d) None of these
Answer:
(d) None of these

Question 22.
The most common and abundant greenhouse gas is
(a) methane
(b) CFC
(c) carbon dioxide
(d) nitrous oxide
Answer:
(c) Carbon dioxide

Question 23.
Women empowerment in Tehri-Garhwal by Sundarlal Bahuguna for the conservation of forests is popularly known as
(a) agro forestry
(b) shifting cultivation
(c) Chipko movement
(d) None of these
Answer:
(c) Chipko movement

Correct the following sentences, if required, by changing the underlined word (s)

Question 1.
Acid rain, a secondary effect of sound pollution.
Answer:
air pollution

Question 2.
The excessive growth of plants in water bodies due to enrichment of nutrients is called bioremediation.
Answer:
Eutrophication

Question 3.
Excessive nourishment that causes algal bloom is known as biomagnification.
Answer:
eutrophication

Question 4.
Photochemical smog consists of O₂ PAN and NO_x.
Answer:
It is Correct

Question 5.
Radioactive pollution is caused by α, ß, γ particles.
Answer:
It is Correct

Question 6.
Ozone hole is present above Antarctica.
Answer:
It is correct.

Question 7.
Greenhouse effect refers to cooling of earth.
Answer:
warming

Question 8.
Nitrogen is a greenhouse gas.
Answer:
Carbon dioxide

Fill in the blanks

Question 1.
Bhopal gas tragedy was due to the release of ……….. gas from Union Carbide’s pesticide plant.
Answer:
methyl isocyanate

Question 2.
The toxic metal that is used as an antiknocking agent in petrol engines of automobiles is ………… .
Answer:
lead (Pb)

Question 3.
The Bharat Emission Norm came into force from ……….. .
Answer:
2000

Question 4.
In a scrubber, the effluent containing sulphur dioxide is passed through spray of ………….. .
Answer:
lime or Water

Question 5.
Most hazardous metal pollutant of automobile exhaust is ……….. .
Answer:
CO

Question 6.
Melting of glaciers is an effect of ………… .
Answer:
global warming

Question 7.
Two greenhouse gases produced by anaerobes are ……….. and ………… .
Answer:
methane, carbon dioxide

Question 8.
In 1980s, the government of India introduced a concept known as ………… .
Answer:
Joint Forest Management

Express in one or two word(s)

Question 1.
The expression that reflects the depleted oxygen content in the extremely polluted water.
Answer:
Biochemical Oxygen Demand (BOD).

Question 2.
Expand DDT.
Answer:
Dichloro Diphenyl Trichloroethane.

Question 3.
Name the gas which was released during Bhopal gas tragedy.
Answer:
Methyl isocyanate

Question 4.
Which metal causes gangrenes?
Answer:
Arsenic

Question 5.
In which year Copenhagen conference was held?
Answer:
2009

Question 6.
In which year was Montreal Protocol signed?
Answer:
1987

Question 7.
Above which region of earth is ozone hole located?
Answer:
Antarctic region

Short Answer Type Questions

Question 1.
State the function of catalytic converter in automobile. Name any two metals used in these converters.
Answer:
Catalytic converters are used in automobiles to reduce the emission of poisonous gases. They convert unburnt hydrocarbons to carbon dioxide and water, carbon monoxide and nitrogen dioxide are converted to carbon dioxide and nitrogen gas respectively.

Question 2.
What are causes of air pollution?
Answer:
The various causes of air pollution are

• Smoke stacks of thermal power plants, forest fires, volcanic eruptions, etc.
• Garbage decomposition releases unwanted gases in the air.
• Excessive use of fossil fuels by automobiles and particulate air pollutants released by industries.

Question 3.
Write a short note on water pollution.
Answer:
Water pollution is any undesirable change in the physical, chemical or biological properties of water that may affect the human beings and aquatic species.
There are various types of water pollutants such as

• Domestic sewage
• Industrial waste
• Agricultural waste

The various effects of water pollution are

• Biomagnification
• Eutrophication
• Increase in Biochemical Oxygen Demand (BOD).

Question 4.
Write short note on algal bloom.
Answer:
Algal bloom is excessive growth of planktonic (free-floating) algae in aquatic bodies due to nutrient enrichment by sewage. It causes fish mortality and deterioration of water quality.

Question 5.
What is BOD?
Answer:
BOD (Biochemical Oxygen Demand) it is the amount of oxygen required by the microorganisms in milligram to breakdown the organic matter in water. Polluted water rises the BOD value of water. Also high BOD causes death of aquatic organisms.

Question 6.
What are the sources of radioactive pollution?
Answer:
Following are the sources of radioactive pollution

• Cosmic rays and radiations
• Nuclear weapons
• Nuclear reactors and fuels
• Radioactive isotopes
• Research and medicines.

Question 7.
Write a note on biomagnification.
Answer:
Biomagnification is defined as the increase in concentration of toxicants at successive trophic levels. Mercury and DDT are well known for biological magnification. Toxic materials cannot be metabolised or excreted. Therefore, they get accumulated in an organism and pass on to higher trophic levels, e.g. DDT accumulates in birds and disturbs calcium metabolism which result in thinning of egg shell. This results in decline of bird population.

Question 8.
Write a note on secondary treatment of sewage.
Answer:
Secondary Treatment of Sewage
1. This treatment is also known as biological treatment because it involves the use of microbes or biota for the treatment of sewage. The effluent from primary treatment is passed into large aeration tanks where it is constantly mechanically agitated and air is pumped into.

2. This air helps in the growth of useful aerobic microbes into floes (masses of bacteria associated with fungal filament to form mesh-likes structures). While growing, these microbes consume major part of the organic matter converting it into mircrobial biomass and releasing lot of minerals. This significantly reduces the BOD (Biochemical Oxygen Demand).

Question 9.
Name an industry which can cause both air and thermal pollution as well as eutrophication.
Answer:
Some of the industries that may cause air and thermal pollution as well as eutrophication are thermal power plants, refineries, smelting and metallurgical processing units, steel mills, fertiliser producing units and the industries using steam or water as coolant. The chemical released from these industries (if rich in nitrogen and phosphorus) may result in eutrophication.

Question 11.
Biological Oxygen Demand or BOD increases with increase in water pollution. In this reference, answer the questions that follows
(i) At a particular segment of the river near a sugar factory, the BOD is much higher than the normal level. What is it indicative of ?
(ii) What will happen to the dissolved oxygen and living organisms in this part of the river?
Answer:
(i) It indicates that the sugar factory releases organic waste in the water body. To degrade the organic matter, microbes utilise the dissolved oxygen in the water, thereby, reducing the levels of dissolved oxygen and increasing the BOD.
(ii) In this part of river, the dissolved oxygen will be depleted making it difficult for aquatic species to survive. It can result in death of fishes in severe cases.

Question 12.
With the help a flow chart exhibit the events of eutrophication.
Answer:
A flow chart showing eutrophication is given below

Stinking eutrophic lake with coloured and turbid water
↑
Loss of species diversity
↑
Death of aquatic animals including fish
↑
Reduced contents of dissolved oxygen
↑
Increase in organic loading of lake
↑
Death of submerged plants due to reduced light
↑
Biological enrichment of water
(algal bloom, planktonic algae and higher plants)
↑
Nutrient enrichment of water
↑
Draining of inorganic nutrients
↑
A young lake

Question 13.
How does algal bloom cause eutrophication of water body?
Answer:
Algal bloom Domestic sewage is rich in nutrients like nitrogen and phosphorus which favours the growth of algae. It causes fish mortality and deterioration of water quality.
Example of a bloom includes red tide.

Question 14.
Why is there a decline in population of fish-eating birds, when the water body is amidst agricultural fields?
Answer:
The reason for decline in fish-eating birds is biomagnification of toxic substances like DDT and other pesticides from the agricultural fields. The pesticides are applied in the fields for protection of crops.

Washed off to water bodies with irrigation water and rain and are indirectly consumed by the fishes entering the food chain. It get(s) accumulated and their concentration increases with each trophic level. Thus, on reaching fish-eating birds, their concentration will be increased many folds.

The high concentration of DDT interferes with calcium metabolism in birds and causes thinning of eggshells and their premature breaking, ultimately causing decline in bird population.

Question 15.
Discuss briefly the following
(i) Radioactive waste
(ii) Defunct ships and e-waste
Answer:
(i) Radioactive waste Radioactive waste is generated from nuclear power plants, nuclear weapon manufacturing facilities, cancer treating hospitals and research laboratories using radioisotopes in investigations. This waste is to be disposed off safely by observing the standard guideline because if it remains for a very long period and continues to emit ionising radiation, it will be extremely hazardous to health of all forms of life.

(ii) Defunct ships Old defunct ships are broken down in developing countries like India, Bangladesh and Pakistan because of cheap labour and demand for scrap metal. These ships however, possess a number of toxic materials like asbestos, lead, mercury and polychlorinated biphenyls. The people involved in ship breaking are exposed to these toxic materials and thus suffer from various diseases. The coastal areas where ship breaking is undertaken also become polluted.

Question 16.
Why does ozone hole form over Antarctica? How will enhanced ultraviolet radiations affect us?
Answer:
In Antarctica, winter months receive no sunlight and thus the temperature is extremely low (-85° C). It facilitates the formation of ice clouds which provide the catalytic surface on which the chlorine atoms react with ozone and degrade it. This happens with the return of sun to Antarctica in springs (September and October). Thus, ozone hole appears over Antarctica mostly during spring.

It is a large area of thinned ozone layer mainly over Antarctic region. At this point, depletion of ozone has occurred more as compared to the rest of the stratosphere.

Question 17.
Write short note on greenhouse effect.
Answer:
It is a naturally occurring phenomenon that is responsible for heating of earth’s surface and atmosphere due to the presence of certain gases in the atmosphere. In the absence of greenhouse gases the average temperature of earth would have been a chill-18° C reather than the present average of 15°C.

These gases radiate heat energy and a major part of which again comes to earth’s surface thus heating it up once again. This cycle is repeated again and again.
High levels of greenhouse gases (CO₂, CFCs, etc.) in the atmosphere allow the heat waves to reach earth but prevent their escape and the earth becomes warm.
This gradual continuous increase in the average temperature of surface of the earth causes global warming.

Question 18.
Write note on ozone depletion.
Answer:
It is the wearing out or reduction of the amount of ozone in the stratosphere. A number of pollutants enter into the stratosphere and deplete the ozone layer. These include CFCs, CH₄ and N₂O. CFCs are widely used as refrigerants. When they are discharged in the lower part of atmosphere, they move upward and reach the stratosphere.

In stratosphere, UV-rays act on them releasing Cl atoms. Cl degrades ozone, releasing molecular oxyen. Cl atoms are not consumed in the reaction. Hence, once CFCs are added to the stratosphere they have permanent and continuous effects on ozone levels.

Question 19.
What is ozone shield?
Answer:
Ozone layer lies in the stratosphere between 10-50 kms above the earth surface. It absorbs 90% of sun’s hazardous UV-radiation and protects plant and animal life. Thus, it is called as ozone shield.
CFC is largely responsible of ozone depletion which causes skin cancer, cataract and weaken immune system.

Question 20.
What is the common household source of CFCs? How these gases affect the ozonalayer?
Answer:
CFCs are widely used as refrigerants. When they are discharged in the lower part of atmosphere, they move upward and reach the stratosphere. In stratosphere, UV-rays act on them releasing Cl atoms. Cl degrades ozone releasing molecular oxygen. Cl atoms are not consumed in this reaction. Hence, once CFCs are added to the stratosphere, they have permanent and continuous effects on ozone levels.

Question 21.
Write, what was the percentage of forest cover of India at the beginning and at the end of 20th century. How different it is from the one recommended by National Forest Policy?
Answer:
In the beginning of the 20th century, the forest cover was about 30% while towards its end it reduced to only 19.4%. The National Forest Policy of India – recommends approximately 67% forest cover for hilly regions including himalayas, while 33% for plains. However, the situation is contrastingly different.

Question 22.
Name any one greenhouse gas and its possible source of production on a large scale. What are the harmful effects of it?
Answer:
Carbon dioxide is a major greenhouse gas. Various human activities such as combustion of fossil fuels, electricity generation, transportation and industries are sources of its large scale production. Excess of CO₂ is harmful and considered as a pollutant. It is because it traps longer wavelength IR radiations reflected by earth’s surface, thus causing global warming.

Question 23.
It has been recorded that the temperature of the earth’s atmosphere has increased by 0.6°C.
(i) What has caused this increase?
(ii) Explain its consequences.
Answer:

• Increase in the level of greenhouse gases (CO₂,CFCS, etc.) in the atmosphere allow the heat waves to reach earth but prevent their escape and thus, the earth becomes warm.
• Effects of increased temperature are
  • Leads to deleterious changes in environment, resulting into odd climatic changes such as El Nino effect.
  • Melting of polar ice caps which will cause the rise in sea level and many coastal areas may also get submerged.

Question 24.
How does Jhum cultivation promote deforestation?
Answer:
Forests are the providers of timber, fuel wood and other products. Forests also provide habitat to different groups of plants and animals. Forests are cut down for various purposes. Some of the reasons are as follows

• Urbanisation
• Overgrazing by animals
• Forest fires
• Demand of wood and other forest products
• Jhum cultivation.

Slash and bum agriculture is known as Jhum Cultivation in the North-Eastern states of India. In this method, the farmers cut down the trees of the forest and burn the plant remains.
The ash is used as a fertiliser and the land is then used for farming or cattle grazing. After cultivation, the area is left for several years so as to allow its recovery.
This same process is repeated at some other area. In initial days, there was ample recovery time, but now-a-days with increasing population and repeated cultivation, this recovery phase is done away with, resulting in deforestation.

Question 25.
How can slash and burn agriculture become environment friendly?
Answer:
Slash and burn agriculture can become environment friendly if

• small widely scattered plots are used for cultivation, so that the forest ecosystem will not suffer damage.
• crop rotation is used so that soil does not loose its entire fertility.
• keeping cropping period small and follow up (unplanted) period longer.

Question 26.
What is the main idea behind ‘Joint Forest Management Concept’ introduced by the Government of India?
Answer:
The main idea behind joint forest management concept introduced by the Government of India was involving the local communities in forest conservation. This concept was adopted considering the extraordinary courage and dedication the local people showed in protecting the wildlife through the movements like Bishnoi’s movement in Jodhpur and Chipko Movement in Garhwal Himalayas.

Question 27.
Write a note on deforestation and enumerate its consequences.
Answer:
It is the conversion of forested areas to non-forested areas. Almost 40% forests have been lost in the tropics, compared to only 1% in the temperate region.
According to a report by the World Commission on Forests and Sustainable Development (WCFSD), from 6 billion hectares, 8000 years ago, there is a decline of 3.6 billion hectares in 1999 of the forest cover. Similar results were also given by the Food and Agriculture Organisation (FAO).
In India, at the beginning of the 20th century, forest covered area was about 30% of land, whereas by the end of the century, it reduced to 19.4%. This shows the alarming condition of our country.

The loss of trees due to their increased cutting is note worthy. Some of the effects due to deforestation are as follows

• Increased levels of CO₂ concentration in atmosphere.
• Loss of biodiversity due to habitat destruction.
• Disturbed hydrologic cycle.

The Andaman and Nicobar islands are the world’s first evergreen forests. The forests also comprise of local comminutes like the Great Andamanese, the Onge, the Jaracuas and the Sentinelese. But, now their population is decreasing 340 km long. Andaman Trunk road was constructed which went through the evergreen forests.
This resulted in clearing of the forest and the tribal communities like Jaracuas original way of life was eroded.

Question 28.
Why has the National Forest Commission of India recommended a relatively larger forest cover for hills than for plains?
Answer:
It is our moral duty to protect, restore and conserve/preserve the forests as they are highly beneficial for mankind.
In India, around 30% of land was covered by forest in early 20th century, which was reduced to 18-19% by the year 2000. National Forest Commission of India (1988) recommended a relatively large forest cover, i.e. 67% for the hills and 33% for the plains. Recommendation of a large forest area for hills is due to its properties like checking soil erosion, percolation and recharging groundwater, checking landslide and other natural calamities and to maintain the original flora and fauna of hills.

Question 29.
How have human activities caused desertification? Explain.
Answer:
The human activities like deforestation, over-cultivation, unrestricted grazing, poor irrigation practices, result in arid patches of land (deforestation).
When these large barren patches extend and remain unattended for long, a desert is created. Because the formation of fertile top layer of soil takes millions of years, desertification easily takes over.

Question 30.
What do you know about Chipko Movement?
Answer:
Chipko Movement happened in 1974, when local women in Garhwal district of India showed enormous bravery in protecting trees from the axe of contractors by hugging them. This movement was world famous and was globally supported.

Question 31.
Discuss the causes and effects of global warming. What measures need to be taken to control global warming?
Answer:
For causes, effects and control measures of global warming.
It has been estimated by computer application studies that there may be a rise of 3°C by the year 2100 on an average.
The major effects of global warming include

1. Climate Earth temperature has increased by 0.6°C during past century, most of it in last three decades. This increased temperature caused changes in precipitation patterns.
2. Glaciers and ice caps Scientists have proposed that this rise in temperature causes deleterious changes in the environment, resulting in odd climatic changes. Thus, leading to melting of the polar ice caps and Himalayan snow caps.
3. Animals and humans The new warmer temperature conditions lead to eruption of diseases in animals and thousands of species will become extinct in a very short period of time. People from coastal areas will start migrating due to climate change.
4. Ocean and coasts The increase in temperature causes melting of polar ice caps and glaciers. This will result in the rise of ocean water level. The increased level of ocean water will cause the submerging of many island nations and coastal cities. The high temperature will cause accelerated vanishing of coral reefs.
5. Water and agriculture The increased temperature will cause decreased productivity in agricultural practice.

Question 32.
Discuss briefly the following
(i) Greenhouse effect
(ii) Ultraviolet-B
Answer:
(i) It is a naturally occurring phenomenon that is responsible for heating of earth’s surface and atmosphere due to the presence of certain gases in the atmosphere. In the absence of greenhouse gases the average temperature of earth would have been a chill-18° C reather than the present average of 15°C.
These gases radiate heat energy and a major part of which again comes to earth’s surface thus heating it up once again. This cycle is repeated again and again.
High levels of greenhouse gases (CO₂, CFCs, etc.) in the atmosphere allow the heat waves to reach earth but prevent their escape and the earth becomes warm.
This gradual continuous increase in the average temperature of surface of the earth causes global warming.

(ii) Ultraviolet-B It is an electromagnetic radiation which has a shorter wavelength than visible light.
It is a harmful radiation that comes from sunlight and penetrates through the ozone hole to the . earth’s surface. It causes many health hazards in humans. UV-B damages DNA and activates the process of skin ageing. It also causes skin darkening and skin cancer. High levels of UV-B cause corneal cataract in human beings.

Question 33.
What depletes ozone in the stratosphere? How does this affect human life?
Answer:
Ozone in the stratosphere is depleted by CFCs, i.e chlorofluorocarbons, released primarily from refrigerators and other industrial emissions.
This affects the human life as it leads to more exposure of UV-radiation, which is considered to be harmful for health. For effects of UV-radiation on human health.
These radations can cause skin cancer, weaker immunity cataract and loss of plant productivity. The thickness of ozone in a column of air from the ground to the top of the atmosphere is measured in terms of Dobson Units (DU).

Differentiate between the following (for complete chapter)

Question 1.
Biomagnification and Eutrophication.
Answer:
Differences between biomagnification and eutrophication are as follows

Biomagnification	Eutrophication
It is the progressive increase in concentration of non-biodegradable substances in the food chain.	It is the enrichment of the water body with plant nutrients like fertilisers from outside.
It is found in all types of ecosystems.	It is found only in aquatic ecosystem and leads to organic loading.
It leads to toxicity in higher order consumers.	It leads to death of most animals and plants in the affected water body.

Question 2.
Deforestation and Reforestation.
Answer:
Differences between deforestation and reforestation are as follows

Deforestation	Reforestation
It is indiscriminate cutting down of trees for human usage.	It involves the planting of new trees in place of the ones cut down.
This reduces the green cover of the particular area.	It is to increase the green cover of a deforested area.
It leads to decline in habitats and biodiversity.	It is done in order to safeguard biodiversity.

Question 3.
Point and Non-point sources of water pollution.
Answer:
Differences between point source of water pollution and non-point source of water pollution are as follows

Point source of water pollution	Non-point source of water pollution
It is pollution caused by discharge of effluents at one point.	It is pollution caused by discharge of pollutants over a wide area.
Due to large scale entry of pollutants at one point the contamination and harmful effect on quality of water is maximum.	There is some dilution of the effect of pollutants due to large size of area.
Treatment plant can be installed in the area of flow of effluents.	Treatment plant is useless for this type of pollution.
Other type of control measures are not required.	Control measures are required on a large scale for non-liberation of pollutants.

Question 4.
Biodegradable pollutants and Non-biodegradable pollutants.
Answer:
Differences between biodegradable pollutants and non-biodegradable pollutauts are as follows

Biodegradable pollutants	Non-biodegradable pollutants
They are those pollutants which are decomposed and degraded by microbes.	The pollutants are not decomposed by microbes.
The pollutants are degraded quite rapidly.	They are degraded very slowly.
Biodegradable pollutants do not pile up.	They often get accumulated.
They can be used to produce energy, manure compost and biogas.	Some of the pollutants of properly separated can be recycled others are not manageable.
They become part of rapid-turnover in biogeochemical cycles.	Many of them do not enter biogeochemical cycles. Others are very slow and often toxic.
Examples garbage, sewage, livestock.	Examples DDT, BHC, plastics, polyethylene, cans, broken glass, etc.

Question 5.
Herbicides and Insecticides
Answer:
Differences between herbicides and insecticides are as follows

Herbicides	Insecticides
These are a type of pesticides used to kill undesirable plants or weeds.	These are type of pesticides that are used to specifically target and kill insects.
Some herbicides kill all the plants they come in contact with, while others are designee to target one species.	The targets are fixed, e.g. snail bait, ant killer and i wasp killer.

Question 6.
Acid rain and Global warming.
Answer:
Difference between acid rain and global warming are as follows

Acid rain	Global warming
Acid rain is the name given to rain, snow or sleet contaminated with acid substance. This occurs when the rain water combines with nitric and sulphuric acids.	Global warming is when the earth’s temperature rises. It happens when carbon dioxide, water vapour, nitrous oxide and methane trap heat and light from the sun in the earth’s atmosphere, which increases the temperature.

Odisha State Board CHSE Odisha Class 12 Biology Important Questions Chapter 16 Biodiversity and its Conservation and Environment Important Questions and Answers.

CHSE Odisha 12th Class Biology Important Questions Chapter 16 Biodiversity and its Conservation

Biodiversity and its Conservation Class 12 Important Questions CHSE Odisha

Very Short Answer Type Questions

Choose the correct option

Question 1.
Indian Giant squirrel in endemic to
(a) Uttar Pradesh
(b) West Bengal
(c) Madhya Pradesh
(d) Manipur
Answer:
(c) Madhya Pradesh

Question 2.
Species richness in any habitat is related to
(a) genetic diversity
(b) species diversity
(c) ecosystem diversity
(d) None of these
Answer:
(b) species diversity

Question 3.
As per IUCN nomenclature, diversity of species across a wide geographical range is called
(a) alpha
(b) beta
(c) gamma
(d) community
Answer:
(c) gamma

Question 4.
Biodiversity is rich in tropics because of
(a) high humidity
(b) stable climate
(c) older community
(d) All of these
Answer:
(d) All of these

Question 5.
The organisation which publishes the Red List of species is
(a) WWF
(b) ICFRE
(c) IUCN
(d) UNEP
Answer:
(c) IUCN

Question 6.
Red Data List was initiated in
(a) 1859
(b) 1963
(c) 1985
(d) 1977
Answer:
(b) 1963

Question 7.
As per the Red List published by the World conservation union, Indian Cheetah is categorised as …………. .
(a) vulnerable
(b) extinct
(c) critically endangered
(d) endangered
Answer:
(b) extinct

Question 8.
Diversity at the level of community and ecosystem is
(a) α – diversity
(b) β – diversity
(c) γ – diversity
(d) All of these
Answer:
(b) β – diversity

Question 9.
Red Data Book is mainted by
(a) CITES
(b) WCU
(c) CBD
(d) IUPAC
Answer:
(b) WCU

Question 10.
Which one is endangered species?
(a) Asiatic lion
(b) Sparrow
(c) Elephant
(d) Dodo
Answer:
(a) Asiatic lion

Question 11.
Which one of the following is not included under in situ conservation?
(a) Wildlife sanctuary
(b) Zoological garden
(c) Biosphere reserve
(d) National park
Answer:
(b) Zoological garden

Question 12.
Conservation and maintenance of wildlife within the natural ecosystem is
(a) in situ conservation
(b) ex situ conservation
(c) botanical gardens
(d) All of the above
Answer:
(a) in situ conservation

Question 13.
In a national park, protection is provided to
(a) entire ecosystem
(b) only fauna
(c) only flora
(d) Both (b) and (c)
Answer:
(a) entire ecosystem

Question 14.
In which zone, limited permitted?
(a) Core zone
(b) Buffer zone
(c) Manipulation zone
(d) Restoration zone
Answer:
(b) Buffer zone

Question 15.
Ramsar convention was held in
(a) India
(b) Iran
(c) Indonesia
(d) Isroel
Answer:
(b) Iran

Question 16.
Bandipur national park is situated in
(a) Kerala
(b) Odisha
(c) Karnataka
(d) Rajasthan
Answer:
(c) Karnataka

Question 17.
The objective of ‘Ramsar convention’ was
(a) forest conservation
(b) wildlife conservation
(c) wetland conservation
(d) biodiversity conservation
Answer:
(c) wetland conservation

Fill in the blanks

Question 1.
Diversity within a community is ……….. .
Answer:
α-diversity.

Question 2.
…………, a struggling shrub from tropical America was introduced as ornamental plant in India has become invasive in the wild.
Answer:
Lantana

Question 3.
A taxon facing high risk of extinction in the wild is ………… .
Answer:
vulnerable

Question 4.
Beaver is a ……….. species
Answer:
keystone

Question 5.
In India hotspots include Western Ghats and ………… .
Answer:
Eastern Himalayas.

Question 6.
The Earth Summit was held in …………. 1992.
Answer:
Brazil

Question 7.
The outer part of biosphere reserve is called ………… .
Answer:
buffer zone.

Question 8.
Wildlife Protection Act was enacted in the year ………. by Government of India.
Answer:
1972

Question 9.
Panna biosphere reserve is located in ……….. .
Answer:
Madhya Pradesh

Question 10.
Private ownership is not permitted in ………… .
Answer:
National Parks

Correct the statement, if required by changing the underlined word

Question 1.
Species diversity decreases as we move away from the equator.
Answer:
Correct statement

Question 2.
Eichhomia called as ‘Terror of Bengal’ is a keystone species.
Answer:
alien species.

Question 3.
The number of species per unit area is ß-diversity.
Answer:
species richness

Question 4.
Zoos, botanical gardens, culture collections are types of ex situ biodiversity conservation.
Answer:
in situ

Question 5.
Exploitation of soil and flora is done in a wildlife sanctuary.
Answer:
Conservation of fauna and flora

Question 6.
The transitional zone of a biosphere reserve is strictly protected to maintain the ecological diversity and integity.
Answer:
core zone

Question 7.
In situ conservation is the conservation of biological diversity outside the boundaries of their natural habitats.
Answer:
ex situ conservation

Express in one or two words

Question 1.
Diversity among individuals of a species.
Answer:
Genetic diversity

Question 2.
The extinction of these species reduces abundance of other species in the community
Answer:
keystone species.

Question 3.
The variety of species within a community.
Answer:
Species diversity

Question 4.
The scientist who developed the concept of hotspots of biodiversity?
Answer:
Norman Myers.

Question 5.
A protected area dedicated to animals life only.
Answer:
Wildlife sanctuaries.

Short Answer Type Questions

Question 1.
Write briefly about the three levels of biological diversity.
Answer:
There are three levels of biological diversity

• Genetic diversity Variations in the genetic composition of individuals within a species or. among species is known as genetic diversity.
• Species diversity It pertains to the variety of species present in a particular area or ecosystem.
• Ecosystem diversity It refers to diversity of habitats, e.g. terrestrial and aquatic ecosystem.

Question 2.
State the importance of species diversity to the ecosystem.
Answer:
The importance of species diversity to the ecosystem are

• Increased biodiversity provides resistance to the ecosystem against natural disasters.
• Ecosystem with more species shows more yields and greater productivity with variation of biomass.
• Community with more species generally tends to be more stable than those with less species.

Question 3.
Species diversity decreases as we move away from the equator towards the poles. What could be the possible reasons?
Answer:
Species diversity decreases as we move towards the poles, because

1. temperature decreases and conditions become harsh.
2. both the amount and intensity of solar radiation decreases.
3. vegetation decreases.
4. less resources available to support species. Speciation is generally a function of time and environmental stability, so if conditions are too harsh, it is difficult for the species to survive and adapt. This results in decrease in biodiversity towards the poles.

Question 4.
Explain giving three reasons why tropic show, greatest levels of species diversity.
Or
Give three hypothesis for explaining, why tropics show greatest level of species richness.
Answer:
It is the variety in the number and richness of a species of a region. Sometimes, a species remains confined to a particular area and is found only in that area. Such species are said to be endemic, e.g., Indian giant squirrel is endemic to Panchmarhi hills in Madhya Pradesh.

The IUCN (International Union for Conservation of Nature and Natural Resources) recognises three types of species diversity, i.e.

1. Alpha (α) diversity It refers to the variety of species within a community. It is also referred to as species richness, i.e., the number of species per unit area.
2. Beta (β) diversity It refers to the diversity of species among communities.
3. Gamma (γ) diversity It refers to the diversity of species across a wide geographical range.

Question 5.
How is biodiversity important for ecosystem functioning?
Answer:
Nature always key a check on these activities to maintain a state of equilibrium (homeostasis), which further helps in the sustainable development of resources. However, overexploitation of biolgical resources by humans leads to destabilisation of ecosystem balance.
For example,

1. Decreased flora of an area leads to CO₂ increase in the atmosphere which causes temperature elevation of that area.
2. Increased carnivore population decreases the . herbivore population by predation which then increase the vegetation.
3. Declined population of microflora prevents the recycling between complex organic matter and simple inorganic matter.

Question 6.
What is a keystone species? Give an example.
Answer:
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species are important in maintaining the structure of an ecological community by affecting other organisms in an ecosystem and helping to determine the abundance of other species in the community, e.g. beaver (a mammal) who creates dams, modifies nutrient cycling, influences decomposition dynamics which ultimately influences the plants and animals of that area.

Question 7.
Write an account on loss of biodiversity in the world.
Answer:
The loss of biodiversity is a global crisis. Extinction of species is a natural phenomenon aided by the physical changes in the environment. However, the accelerated rates of species extinctions, that the world is facing now are largely due to human activities.

Till now, five episodes of mass extinction of species have occured in the history of biological evolution. The sixth episode of extinction of species however, is credited to human activities, which otherwise would not have occurred.

Question 8.
How does habitat fragmentation cause depletion of biodiversity?
Answer:
When large habitats are broken up into small fragments due to the various human activities, mammals and birds requiring large territories and certain animals with migratory habits are badly affected, leading to their population decline.

Question 9.
Briefly classify the extinction processes.
Answer:
The extinction of species is a natural process. Many species have disappeared and new ones have evolved to take over their place. There are three types of extinction processes

1. Natural extinction When there is change in environmental conditions, certain species disappear and others, (which are more adapted to changed conditions) take their place. This loss of species that occurred in the geological past at a very slow rate is known as natural extinction.
2. Mass extinction There have been several periods in the earth’s geological history when large number of species become extinct due to catastrophes, e.g. extinction of dinosaurs in end cretaceous period.
3. Anthropogenic extinctions Recently more number of species is disappearing from the face of the earth due to human activities. Man-made mass extinction represents a very severe depletion of biodiversity.

Question 10.
Since the origin of life on earth, there were five episodes of mass extinction of species.
(i) How is the ‘sixth extinction’, presently in progress, different from the previous episodes?
(ii) Who is mainly responsible for the ‘sixth extinction’?
(iii) List any four points that can help to overcome this disaster.
Answer:
(i) The current species extinction rate are estimated to be 100-1000 times faster than in pre-human times.
(ii) Human activities.
(iii) To prevent sixth extinction to take place we should

• prevent habitat loss and fragmentation.
• check over exploitation.
• prevent alien species invasion.
• prevent coextinction.
• conservation and preservation of species

Question 11.
How is diversity at all levels generally conserved?
Ans.
Diversity is recognised by gene pool, species and biotic community. The ecosystem is affected by changes due to the pollution, climatic changes and overexploitation, etc. There is need to prevent further destruction or degradation of habitats in order to conserve the biodiversity. These are on site (in situ) and off site (ex situ) strategies of conservation. Protected areas like national parks, sanctuaries and biosphere reserves also helps to maintain diversity.

Question 12.
State the significances of ex situ conservation.
Answer:
Ex situ conservation is outside conservation strategy, in which zoos help in captive breeding of organisms which are endangered, whereas botanical gardens have seed gene banks, tissue culture labs and other technologies for storing and growing germplasm.

Question 13.
There are many animals that have become extinct in the wild, but continue to be maintained in zoological parks.
(i) Which type of biodiversity conservation is observed in this case?
(ii) Name any other two ways, which help in this type of conservation?
Answer:
(i) It is an example of ex situ (off site) conservation. In this approach, threatened plants and animals are taken out of their natural habitat and placed in suitable settings and given special care.
(ii) Ciyopreservation and tissue culture are two ways that help in ex situ conservation.

Question 14.
Which type of conservation measures, in situ or ex situ will help the larger number species to survive? Explain.
Answer:
Out of the two, the in situ conservation measures will help in the survival of larger number of species.
In situ is onsite conservation, which implies that species are conserved in their natural habitat.
To conserve species in their natural habitat, the entire ecosystem has to be conserved, which include other organisms, biotic and abiotic component of the ecosystem associated with the target species.
Hence, in situ conservation helps in the survival of larger number of species.

Question 15.
What do you mean by national park?
Or
Write a note on national park.
Answer:
A national park is an area dedicated to conserve the environment, natural and historical objects and the wildlife therein. It also aims to provide enjoyment in such a manner and by such a means that will leave them unimpaired for the enjoyment of the future generations, e.g. Jim Corbett National Park, Uttarakhand.

Question 16.
What are hotspots of biodiversity?
Or
Write a note on biodiversity hotspots.
Answer:
Hotspots are areas that are extremely rich in species diversity, have high endemism and are under constant threat of extinction. Out of the total hotspots of the world, three are found in India.
They are Eastern Himalayas which extends from North-Eastern India to Bhutan, Western Ghats which include forests that lie in the states such as Karnataka, Maharashtra and Tamil Nadu and Indo-Burma region.

Question 17.
What is biosphere reserve? Mention its zones.
Or
Briefly discuss the four zones of biosphere reserve.
Answer:
A biosphere reserve is a specified area in which multiple use of the land is permitted. It is divided into four stones
(i) Core zone It is the innermost and legally protected where no human activity is allowed.
(ii) Buffer zone Here, limited human activity is allowed, like sustainable and recreational activities.
(iii) Transitional zone Anthropogenic activities like research and sustainable development is allowed.
(iv) Zone of human encroachment Here, normal anthropogenic activities are allowed.

Differentiate between the following (for complete chapter)

Question 1.
Sanctuary reserve and Biosphere reserve.
Answer:
Differences between sanctuary reserve and biosphere reserve are as follows

Sanctuary reserve	Biosphere reserve
Attention is not given to biotic community, i.e. conservation is species oriented.	Attention is focused on biotic community as a whole, i.e. conservation is ecosystem oriented.
Limits are not circumscribed.	Boundaries are circumscribed by the state legislation.
There occurs limited biotic interference.	There occurs no biotic interference except in buffer zone.
Tourism in a sanctuary is permissible.	Tourism is not permissible inside biosphere reserve
Research and scientific management are lacking.	Research and scientific management are carried out.
Proper attention is not given to gene pool conservation of economic species, particularly in plants.	Due attention is given to the conservation of plants as well as animal species.

Question 2.
Beta (β) diversity and Gamma (γ) diversity.
Answer:
Differences between beta diversity and gamma diversity are as follows

Beta (β) diversity	Gamma (γ) diversity
It is diversity of species among communities.	It refers to the diversity of species across a wide geographical range.
It develops due to change in habitat of community along environment gradients.	It represents the total richness of species in all the habitats found within a region, geographical areas or landscape.
When the difference of species between the habitats is greater, it represents greater Beta-diversity.	When each habitat has a unique biota, gamma diversity is equal to average alpha diversity multiplied by the number of such habitats.

Question 3.
Species diversity and Ecological diversity.
Answer:
Differences between species and ecological diversity are as follows

Species diversity	Ecological diversity
It is related to the number, type and distribution of species found in given area.	It is the variety of ecosystems in a biosphere.
It is the trait of the community.	It is the diversity at the level of communities and ecosystems of region.
It is affected not only by the number of individuals, but also by the heterogeneity of the sample.	It is affected directly by the environment.

Question 4.
Alpha (α) diversity and Beta (β) diversity
Answer:
Differences between alpha and beta diversity are as follows

Alpha (α) diversity	Beta (β) diversity
It is the variety of species within a community.	It is diversity of species between communities.
It was defined by Whittaker as the species richness of a place.	It was defined by Whittaker as the extent of species replacement or biotic change along environmental gradients.
A community will have a high alpha diversity, when there is a high number of species and their abundance are much similar.	Beta diversity measures the turnover of species between two sites in terms of gain or loss of species.

Odisha State Board CHSE Odisha Class 12 Biology Important Questions Chapter 15 Ecosystem and Environment Important Questions and Answers.

CHSE Odisha 12th Class Biology Important Questions Chapter 15 Ecosystem

EcosystemClass 12 Important Questions CHSE Odisha

Very Short Answer Type Questions

Choose the correct option

Question 1.
Biotic components include
(a) producers, consumers and decomposers
(b) producers and consumers
(c) Both (a) and (b)
(d) None of the above
Answer:
(a) producers, consumers and decomposers

Question 2.
The non-green plants are as important as green plants because they
(a) cause human diseases
(b) cause diseases of other plants
(c) are useful in several industries
(d) bring about decomposition of dead animal and plant remains
Answer:
(d) bring about decomposition of dead animal and plant remains

Question 3.
Primary consumers are always
(a) producers
(b) carnivores
(c) herbivores
(d) omnivores
Answer:
(c) herbivores

Question 4.
Man is ………… .
(a) herbivorous
(b) carnivorous
(c) omnivorous
(d) producers
Answer:
(c) omnivorous

Question 5.
Secondary producers are
(a) herbivores
(b) producers
(c) carnivores
(d) None of these
Answer:
(d) None of these

Question 6.
Which of the following is an abiotic component of ecosystem?
(a) Bacteria
(b) Humus
(c) Plants
(d) Fungi
Answer:
(b) Humus

Question 7.
Decomposers are generally
(a) green plants
(b) phytoplanktons
(c) insects
(d) microorganisms
Answer:
(d) microorganisms

Question 8.
Abiotic components of an ecosystem include
(a) producers, consumers and decomposers
(b) producers and consumers
(c) only producers
(d) None of the above
Answer:
(d) None of the above

Question 9.
An ecosystem is not a /an
(a) open system
(b) closed system
(c) variable system
(d) None of the above
Answer:
(b) closed system

Question 10.
Trophic levels in ecosystem are formed by
(a) only bacteria
(b) only plants
(c) only herbivores
(d) organisms linked in food chain
Ans.
(d) organisms linked in food chain.

Question 11.
Detritus food chain begins with
(a) virus
(b) bacteria
(c) protozoan
(d) algae
Answer:
(b) bacteria

Question 12.
Which one of the following has the largest population in food chain?
(a) Producers
(b) Primary consumers
(c) Secondary consumers
(d) Decomposers
Answer:
(d) Decomposers.
As, they include microorganisms, they form largest population in a food chain and decompose dead plants and animals.

Question 13.
The second trophic level in a lake is ………….. .
(a) phytoplanktons
(b) zooplanktons
(c) benthos
(d) fishes
Answer:
(b) Zooplanktons.
They are primary consumers in an aquatic food chain who feed upon phytoplanktons.

Question 14.
A food chain can have trophic levels
(a) one
(b) two
(c) three
(d) multiple
Answer:
(d) multiple

Question 15.
Who proposed the concept of ecological pyramid?
(a) Odum
(b) Elton
(c) Tansley
(d) Clements
Answer:
(b) Elton.

Question 16.
Primary succession is development of communities on
(a) cleared forest area
(b) newly exposed habitat
(c) pond filled after a dry season
(d) freshly harvested crop field
Answer:
(b) newly exposed habitat

Question 17.
Lichen is pioneer in which succession?
(a) Hydrosere
(b) Lithosere
(c) Psammosere
(d) Halosere
Answer:
(b) Lithosere

Question 18.
Plant succession in a saline habitat is called
(a) hydrosere
(b) halosere
(c) psammosere
(d) xerosere
Answer:
(b) halosere

Question 19.
The first species that establishes itself in a barren habitat due to succession is called
(a) climax
(b) migrant
(c) colony
(d) pioneer
Answer:
(d) pioneer

Question 20.
When propagating units like seeds and spores enter a barren area to initiate the process of succession, it is called
(a) nudation
(b) reaction
(c) ecesis
(d) migration
Answer:
(c) ecesis

Question 21.
The rate of release of nutrients into atmosphere is regulated by
(a) temperature
(b) soil nature
(c) pH
(d) All of the above
Answer:
(d) All of the above

Question 22.
Weathering of rocks makes phosphorus available first to
(a) producers
(b) decomposers
(c) consumers
(d) None of the above
Answer:
(a) producers

Fill in the blanks

Question 1.
Plants are called as ……….. because they fix carbon dioxide.
Answer:
autotrophs

Question 2.
In an aquatic ecosystem, the limiting factor for the productivity is …….. .
Answer:
sunlight

Question 3.
Decomposers are generally ……… (green plants, microorganisms, phytoplanktons, insects)
Answer:
microorganisms

Question 4.
A detrivore is animal feeding on …………… .
Answer:
dead matter

Question 5.
Productivity is expressed in terms of …………… .
Answer:
g^-2 yr^-1 (kcal m^-2)yr^-1

Question 6.
Amount of energy transferred from one trophic level to next is ………. .
Answer:
10%.

Question 7.
Tip of an ecological pyramid is occupied by ………. .
Answer:
carnivores.

Question 8.
In an ecosystem dominated by trees, the pyramid of number is ………. type.
Answer:
inverted.

Question 9.
Green plants constitute ………….. trophic level.
Answer:
First

Question 10.
………… represents sedimentary type of nutrient cycle.
Answer:
Phosphorus.

Question 11.
In ……….. succession, dominant organisms are autotrophs.
Answer:
autotrophic

Question 12.
The individual transitional communities are called ………. .
Answer:
serai

Correct the statement if required, by changing the underlined word

Question 1.
The term ecosystem was proposed by Odum.
Answer:
Tansley

Question 2.
The two components of an ecosystem are plants and animals.
Answer:
biotic and abiotic.

Question 3.
Carnivores are always primary consumers.
Answer:
Herbivores

Question 4.
The raw material for decomposition is called vermicompost.
Answer:
detritus

Question 5.
Net primary productivity is GPP + R.
Answer:
GPR-R

Question 6.
Out of the total solar energy, PAR is only 1-5%.
Answer:
50%

Question 7.
Phytoplanktons occupy more than one trophic level in pond ecosystem.
Answer:
Fishes.

Question 8.
Pyramid of energy is always inverted.
Answer:
upright.

Question 9.
Pyramid of energy is always inverted.
Answer:
Always upright

Question 10.
Flow of energy declines as it passes from lower to higher trophic level. This is explained by first law of thermodynamics.
Answer:
It is correct.

Question 11.
Plant succession in a sandy area is lithosere.
Answer:
psammosere

Question 12.
The pioneer community in hydrosere is submerged plants.
Answer:
phytoplanktons

Question 13.
Climate control comes under supporting ecosystem services.
Answer:
Primary productivity

Question 14.
The first species that establishes itself in a barren habitat due to succession is called migrant.
Answer:
pioneer species

Question 15.
Lichens and mosses are the part of halosere.
Answer:
xerosere

Express in one or two words

Question 1.
What is the creating force of an ecosystem?
Answer:
Solar energy.

Question 2.
What type of ecosystem is represented by pond?
Answer:
Freshwater ecosystem.

Question 3.
Name the common detritivores in an ecosystem.
Answer:
Earthworms

Question 4.
Name the two basic categories of an ecosystem.
Answer:
Natural and Artificial ecosystem

Question 5.
Name the largest decomposers of forest floor.
Answer:
Microorganisms

Question 6.
Name the term used for rate of storage of organic matter not used by heterotrophs.
Answer:
Gross primary productivity

Question 7.
Name any two organisms, which can occupy more than one trophic level in an ecosystem.
Answer:
Human beings and birds (e.g. sparrow).

Question 8.
State, what does standing crop of a trophic level represent?
Answer:
Standing crop represents total amount of living matter or organic matter present in an ecosystem in an unit area and at a specific time.

Question 9.
List any two ways of measuring the standing crop of a trophic level.
Answer:
Two ways of measuring the standing crop of a trophic level are

• Biomass of living organisms.
• Number in an unit area.

Question 10.
Expand PAR.
Answer:
Photosynthetically Active Radiation

Question 11.
What is the starting point of a grazing food chain and of a detritus food chain?
Answer:
Producers and dead organic matter, respectively.

Question 12.
Which is the major reservoir of carbon on earth?
Answer:
Ocean.

Question 13.
Under what conditions would a particular stage in the process of succession revert back to an earlier stage?
Answer:
Natural or human induced disturbances like fire, deforestation, etc.

Question 14.
Give one examples of xerarch succession.
Answer:
Sand deserts and rock deserts (as there is no water and the substratum does not absorb rainwater).

Question 15.
How much of carbon is dissolved in the oceans?
Answer:
71%

Question 16.
Name the two forms of reservoir of carbon, that regulate the ecosystem carbon cycle.
Answer:
ocean and fossil fuel

Question 17.
How much carbon is fixed in the biosphere through photosynthesis annually?
Answer:
4 × 10¹³ kg

Question 18.
What do you understand by the term serai stage?
Answer:
The individual transitional communities are termed as serai stage.

Short Answer Type Questions

Question 1.
Write a note on ecosystem.
Answer:
Ecosystem is considered as an interactive system, where biotic and abiotic components interact with each other via energy exchange and flow of nutrients. An ecosystem can be either natural or artificial. Natural ecosystems These are capable of maintaining and operating themselves, without the interference of man. They are further classified as

Artificial ecosystems These are maintained and manipulated by man for different purposes, e.g. cropland, aquarium, etc.

Question 2.
Is an aquarium a complete ecosystem?
Or
Can an aquarium be considered a complete ecosystem?
Answer:
Yes, aquarium is a man-made ecosystem (artificial). If an ecosystem possesses all physical and biological components, then it is said to be complete.
Since, aquarium has biotic components (plants and fishes) and abiotic components (air and water) required for survival of fishes so, it is a complete ecosystem.

Question 3.
Apart from plants and animals, microbes form a permanent biotic component in an ecosystem.
While plants have been referred to as autotrophs and animals as heterotrophs, what are microbes referred to as?
Or
How do these microbes fulfil their energy requirements?
Answer:
Microbes are referred to as heterotrophs and saprotrophs. They fulfil their energy requirement by feeding on dead remains of plants and animals through the process of decomposition.

Question 4.
How are productivity, gross primary productivity, net primary productivity and secondary productivity interrelated?
Answer:
A constant input of solar energy is the basic requirement’ for any ecosystem so that the living organisms can survive, grow (make new cells) and maintain their internal orgnisation. The rate of synthesis of energy containing organic matter or biomass per unit area in unit time is called its productivity. It is expressed in terms of g^-2yr^-1 or (kcal m^-2) yr^-1. Productivity of an ecosystem can be categorised as primary and secondary productivity.

Primary Productivity:
It is the amount of biomass or organic matter produced per unit area over a time period by plants due to photosynthesis. It is expressed in terms of weight (g^-2d^-1) or energy (kcal m^-2).
The primary productivity has two aspects as discussed below

Gross Primary Productivity (GPP):
It is the total amount of produced organic matter during photosynthesis. A considerable amount of GPP is utilised or lost by plants in respiration.

Net Primary Productivity (NPP)
It is the available biomass for the consumption by heterotrophs (herbivores and decomposers). It is actually the amount of energy left in the producers after the utilisation of some energy during respiration. Thus, Gross Primary Productivity (GPP) minus the Respiration Losses (R) gives the Net Primary Productivity.

GPP – R = NPP where, R = Respiration losses.
Net primary productivity differs in different communities of plants, e.g.

• In terrestrial community, GPP is 2.7 times of NPP.
• In ocean community, GPP is 1.5 times of NPP.

Secondary Productivity:
It is the rate of assimilation and formation of new organic matter by consumers. It is small as compared to primary productivity and tends to decrease with an increase in the trophic level.

Question 5.
Primary productivity varies from ecosystem to ecosystem. Explain.
Answer:
Primary productivity varies from ecosystem to ecosystem because it depends on the plant species inhabiting the area and their photosynthetic activity. It also depends on various environmental factors like-light, temperature, rain, etc., and nutrient availability which varies in different ecosystems.

Question 6.
(i) What is primary productivity? Why does it vary in different types of ecosystems?
(ii) State the relation between gross and net primary productivity.
Answer:
(i) RIt is the amount of biomass or organic matter produced per unit area over a time period by plants due to photosynthesis. It is expressed in terms of weight (g^-2d^-1) or energy (kcal m^-2).
Primary productivity varies from ecosystem to ecosystem because it depends on the plant species inhabiting the area and their photosynthetic activity. It also depends on various environmental factors like-light, temperature, rain, etc., and nutrient availability which varies in different ecosystems.

(ii) The relation between the gross and net primary productivity can be shown as P_n = P_g – R
where, P_n = Net Primary Productivity (NPP)
P_g = Gross Primary Productivity (GPP)
R = Respiration

Question 7.
Which of the following ecosystems will be more productive in terms of primary productivity? Justify your answer.
A young forest, a natural old forest, a shallow polluted lake, alpine meadow.
Answer:
Primary productivity can be defined as the rate at which primary producers (e.g. green plants) trap and store solar radiation in the form of biomass. This is measured in terms of weight (g^-2) and in terms of energy (kcal m^-2) per year in a given time. So, primary productivity varies from ecosystem to ecosystem and the ecosystem which possesses more producers will be more productive in terms of primary productivity.

So, young forests grow quicker than older mature forests and are more productive in terms of productivity.
The shallow polluted lake and alpine meadow will be less productive because of less number of producers and high amount of dead organic matter.

Question 8.
Why is the rate of assimilation of energy at the herbivore level called secondary productivity?
Answer:
The rate of assimilation of energy at herbivore (primary consumer) level is called secondary productivity because the biomass available to the organisms of this trophic level is a resultant of the primary productivity, which is formed by autotrophs (plants).

Question 9.
Why are oceans least productive?
Answer:
Oceans are least productive because

• there is insufficient radiation as sunlight decreases with the increasing depth of the ocean.
• oceans are nitrogen deficient which is an important nutrient for plants.
• conditions of high salinity in Ocean are not favourable for all plants.
• there is no substratum to support plants.

Question 10.
Write a note on decomposers.
Answer:
The microorganisms that breakdown the dead remains of plants, animals and organic matter into simpler inorganic substances are called decomposers.
These organisms are mainly aerobic and require oxygen-rich conditions to carry out their functioning. Their mode of nutrition is generally saprophytic as they ingest partially digested food material.

Question 11.
The rate of decomposition of detritus is affected by the abiotic factors like availability of oxygen, pH of the soil substratum, temperature, etc. Discuss.
Answer:
It is the process of breaking down of complex organic matter into inorganic substances like water, carbon dioxide and nutrients by decomposers. Detritus is the raw material for decomposition. It includes dead remains of plants (leaves, bark and flowers) and animals including faecal matter. Different steps involved in the process of decomposition are

1. Fragmentation It is the process of breakdown of detritus into smaller particles by detritivores (e.g. earthworm).
2. Leaching It is the process by which water-soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts.
3. Catabolism It is the process of degradation of detritus into simple organic material by the action of bacterial and fungal enzymes and then they are further converted into simpler inorganic compounds.
4. Humification It is a process that leads to the accumulation of a dark coloured amorphous and colloidal substance called humus. It is highly resistant to microbial action and undergoes decomposition at a very slow rate. Being colloidal in nature, it serves as a reservoir of nutrients.
5. Mineralisation It is the process of degradation of humus by microbial action and release of inorganic nutrients.

Some are eaten by insects and other animals. Nutrients and energy enter food web.

Diagrammatic representation of decomposition cycle in a terrestrial ecosystem

Question 11.
Justify the following statement in terms of ecosystem dynamics.
‘Nature tends to increase the gross primary productivity, while man tends to increase the net primary productivity.’
Answer:
Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. So, nature tends to increase gross primary productivity through supporting the large number of plants (producers) in an ecosystem.
Net primary productivity is the available biomass for the consumption by heterotrophs (human and animals).
Man tries to increase net primary productivity by cultivating food and other crops to fulfil their needs.

Question 12.
‘The energy flow in an ecosystem is unidirectional’. Justify the statement.
Answer:
Energy in an ecosystem flows from producers to primary consumers, then from primary consumers to secondary consumers and so on. There is never a backflow of energy, i.e. energy cannot come back to a trophic level it has already passed. Therefore, the energy flow is unidirectional in an ecosystem.

Question 13.
The diagram shows the flow of energy through an ecosystem.

Which arrows represent the smallest amount of energy transferred between organisms and the largest amount of energy lost to the ecosystem?
Answer:
The smallest amount of energy transferred is represented by arrow 2 and largest energy loss by arrow 3.

Question 14.
‘The energy flow in the ecosystem follows the second law of thermodynamics’. Explain.
Answer:
According to second law of thermodynamics, every activity involving energy transformation is accompanied by dissipation of energy as heat and increase in disorderliness, except in deep hydrothermal ecosystems.

This is because out of the total PAR only 2-10% is captured by photosynthetic organisms in synthesis of organic matter. Further, this energy is used during various metabolic processes for the formation of food and a very little is stored as biomass. This trapped energy as biomass is transferred to next trophic level according to Lindeman’s law. Only 10% of the stored energy is passed from one trophic level to successive trophic level.

Question 15.
Organisms at a higher trophic level have less energy available. Comment.
Answer:
Energy flow in the ecosystem follows the 10% energy flow law, proposed by Lindeman. According to this law, only 10% of the energy available at each trophic level, gets transferred to the next trophic level, the rest is lost in the environment as heat.

As we move to higher trophic levels, the energy available to organisms keeps on decreasing. Thus, the top . carnivore gains the least energy in a food chain.

Question 16.
The number of trophic levels in an ecosystem are limited. Comment.
Answer:
The number of trophic levels in an ecosystem are limited and are not more than 3-4. Because the amount of energy flow decreases with successive trophic level, as only 10% of energy is transferred from one trophic level . to the next trophic level.
So, rest of the energy is lost in the form of respiration and other vital activities to maintain life. If more trophic levels are present, the residual energy will be limited and will decrease to such an extent that it cannot further support any trophic level. So, the food chain is generally limited to 3-4 trophic levels only.

Question 17.
Write a short note on food chain.
Answer:
The transfer of energy from green plants through a sequence of organisms, in which each eats the one below it in the chain and is eaten by the one above is called a food chain. It is actually a feeding chain of organisms in an ecosystem.

Based on the relationship among the organisms and the source of their nutrition or food, organisms occupy a specific place in the food chain that is known as their trophic level. An assemblage of trophic levels within the ecosystem is known as trophic structure.
A single species may occupy multiple trophic levels in a food.
Example

• Grass → Grasshopper → Frog → Snake → Eagle.
• Grass → Goat → Man

Question 18.
Three food chains are shown below
(i) Grass → Deer → Tiger
(ii) Tree → Beetle → Bacteria
(iii) Flowering plant → Butterfly → Bird
They can be represented by the three pyramids of numbers P, Q and R below

Write the correct combination that correctly matches food chains and pyramids.
Answer:
P → 3, Q → 1, R → 2

Question 19
Define ecological pyramids and describe with examples, pyramids of number and biomass.
Or
Write a short note on ecological pyramids.
Answer:
Ecological pyramids are diagrammatic illustrations of connection between different trophic levels in terms of energy, biomass and number of organisms.
Pyramid of biomass can be both upright and inverted. This can be understood from the examples given below

1. The pyramid of biomass in a pond ecosystem is inverted. Because, the sum total of the weight of phytoplankton (producer) is far less than a few fishes feeding on them, at higher trophic levels.
2. Pyramid of biomass in a forest ecosystem is upright because producers are more in biomass than primary consumers. Primary consumers are more than secondary consumers and secondary consumers are more than tertiary consumers (top).

Pyramid of energy is never inverted (i.e. it is always upright). Because, when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step.
Each bar in the energy pyramid indicates the amount of energy present at each trophic level in a given time.

Question 20.
Write a note on pyramid of energy.
Answer:
Pyramid of Energy
It represents the total amount of energy utilised by different trophic level organisms in unit area over a period of time.

An ideal pyramid of energy with primary producers storing only 196 of solar energy as NPP

Its unit is kj/ha/yr. Pyramid of energy is always upright, i. e. it can never be inverted, because when energy is transferred from a particular trophic level to the next trophic level, some energy is always lost as heat at each step. It is in accordance with the first law of thermodynamics which states that energy is always conserved, it is neither created nor destroyed.

Question 21.
Fill in the missing stages in the given primary hydrarch succession.
Phytoplankton → A → B → C → Submerged free-floating → D → Forest plant stage
Answer:
A – Reed-swamp stage
B – Submerged plant stage
C – Marsh-meadow stage
D – Shrub stage.

Question 22.
Mention the role of pioneer species in primary succession on rocks.
Answer:
Lichens are pioneer species in primary succession on rocks. They secrete organic acids, which wither the rock and help in soil formation. Lichens by forming soil pave way for the next community, i.e. bryophytes.

Question 23.
Write the notes on the following
(i) Define pioneer species.
(ii) Among bryophytes, lichens and fern, which one is a pioneer species in a xeric succession and why?
Answer:
(i) The species that invade a bare area are called pioneer species.
(ii) In a xeric succession, the pioneer species are usually lichens then bryophytes, which are succeeded by ferns and some other bigger plants.

Lichen produces lichen acid and carbonic acid which corrode rock surface and release minerals required for growth. The corroded rock accumulates soil particle by wind and provides substrate for bryophytes and ferns.

Question 24.
State the function of a reservoir in a nutrient cycle. Explain the simplified model of carbon cycle in nature.
Answer:
The function of reservoir is to meet the deficit which occurs due to imbalance in the rate of influx and efflux.

Question 25.
Why are nutrient cycles in nature called biogeochemical cycles?
Answer:
Nutrient cycles are called biogeochemical cycles because ions/molecules of a nutrient are transferred from the environment (rocks, air and water) to organisms (life) and then brought back to the environment in a cyclic pathway.
The literal meaning of biogeochemical is bio – living organism and geo – rocks, air and water.

Question 26.
Outline the salient features of carbon cycle in an ecosystem.
Answer:
Carbon constitutes 45% of dry weight of organisms and it is next only to water. About 71% carbon is found dissolved in oceans. This oceanic reservoir regulates the amount of carbon dioxide (CO₂) in the atmosphere. The fossil fuels also represent a reservoir of carbon.Therefore, carbon cycling occurs through atmosphere, ocean and through living and dead organisms.

Approximately, 4 × 10¹³ kg of carbon is fixed in the biosphere through photosynthesis annually. Carbon-fixation or carbon assimilation refers to the conversion process of inorganic carbon (carbon dioxide) into organic compound. CO₂ is returned to the atmosphere via respiratory activities of producers and consumers. Decomposers also contribute substantially to CO₂ pool by their processing of waste materials and dead organic matter of land or oceans.

Various activites like burning of wood, forest fire and cqmbustion of organic matter, fossil fuels and volcanic eruption contributes to additional sources of CO₂ release into the atmosphere.
Human activities have significantly influenced the carbon cycle, e.g. rapid deforestation and burning of fossil fuel for energy and transport have significantly increased the rate of release of carbon dioxide into the atmosphere.

Question 27.
Complete the following model of carbon cycle by filling A, B, C, D, E and F.

Answer:
A – Respiration,
B – Photosynthesis,
C – Respiration,
D – Combustion of fossil fuels
E – Aquatic food chain and
E – Coal and oil.

Question 28.
Write important features of a sedimentary cycle in an ecosystem.
Answer:
Phosphorus cycle is an example of sedimentary nutrient cycle, since, it moves from land to the sediments at the bottom of the seas, then back to land again. The natural reservoir of phosphorus is earth’s crust. Rocks contain phosphorus in the form of phosphates.

By weathering and soil erosion, phosphates enter streams, rivers and then to oceans. With great movements of the tectonic plates, sea floor is uplifted and phosphates become exposed to the drained land surfaces. From here, weathering for a long period of time releases phosphates from rocks. Minute amount of these phosphates dissolve in soil and are absorbed by the roots of the plants. Herbivores and other animals obtain this element from the plants.

Question 29.
Describe the advantages for keeping the ecosystems healthy.
Or
Write a short note on ecosystem services.
Answer:
The various benefits that humans obtain from the ecosystem are collectively called ecosystem services.
The advantages of keeping an ecosystem healthy can be grouped into following types

Healthy ecosystems are the base for a wide range of economic, environmental and aesthetic goods and services. Ecosystem services are the products of ecosystem processes, e.g. healthy forest ecosystem purifies air and water, mitigates droughts and floods, cycles nutrients, generates fertile soils, provides wildlife habitat, maintains biodiversity, pollinates crops, provides storage site for carbon and also provides aesthetic, cultural and spiritual values.

Although it is difficult to find out the monitory value of all these services, still it is reasonable to think that biodiversity should carry a hefty price tag.

Robert Constanza and his colleagues recently have tried to put price tag on the nature’s life-support services. Researchers have put a price tag of US $ 33 trillion a year on these fundamental ecosystem services, which we utilise for free. This is almost twice the value of global Gross National Product (GNP), which is of US $ 18 trillion. Out of the total cost of various ecosystem services, soil formation accounts for 50%.

Contribution of other services like recreation and nutrient cycling are less than 10% each. The cost of climate regulation and habitat for wildlife are about 6% each.

Differentiate between the following (for complete chapter)

Question 1.
Standing crop and Standing state.
Answer:
Differences between standing crop and standing state are as follows

Standing crop	Standing state
It is amount of biomass present in an ecosystem.	It is amount of inorganic nutrients found in an ecosystem.
It represents the entire living matter.	It represents a part of non-living matter.
There is no circulation of this matter.	It circulates between living and non-living components of the ecosystem.
Continuous synthesis and consumption of biomass goes on.	It is being regularly depleted and replenished by the living matter.

Question 2.
Primary productivity and Secondary productivity.
Answer:
Differences between primary productivity and secondary productivity are as follows

Primary productivity	Secondary productivity
It is the rate of synthesis of organic matter by producers.	It is the rate of synthesis of organic matter by consumers.
It is comparatively quite high.	It is small and decreases with rise of trophic level.
It is due to synthesis of fresh organic matter from inorganic raw materials.	It is due to synthesis of organic matter from organic matter.

Question 3.
Detritivores and Decomposers.
Answer:
Differences between detritivores and decomposers are as follows

Detritivores	Decomposers
These are animals which feed on detritus.	These are microorganisms which obtain nourishment from organic remains.
These ingest the organic matter.	These decompose the organic matter by secreting digestive enzymes over it.
Ecologically, they cause pulverisation or fragmentation of detritus, e.g. earthworm, carrion beetle.	Ecologically, they cause humification and mineralisation of organic matter, e.g. Pseudomonas, slime moulds.

Question 4.
Production and Decomposition.
Answer:
Differences between production and decomposition are as follows

Production	Decomposition
It is the process of synthesis organic compounds/biomass from inorganic matter using sunlight by producers (e.g. plants).	It is the process of of breaking down of a substance/waste biomass into its constituent parts by decomposers, e.g. bacteria, fungi.
It traps the energy.	It releases the energy.
It builds up biomass from inorganic nutrients.	It releases inorganic nutrients from the biomass.

Odisha State Board CHSE Odisha Class 12 Biology Important Questions Chapter 14 Organisms and Environment Important Questions and Answers.

CHSE Odisha 12th Class Biology Important Questions Chapter 14 Organisms and Environment

Organisms and Environment Class 12 Important Questions CHSE Odisha

Very Short Answer Type Questions

Choose the correct option

Question 1.
Plants and animals living in a particular area constitute
(a) flora and fauna
(b) community
(c) ecosystem
(d) ecology
Ans.
(b) community

Question 2.
Biome is defined as
(a) sum of ecosystem in a geographical area
(b) sum of ecosystem of the whole earth
(c) biotic potential of a population
(d) biotic component of a ecosystem
Ans.
(a) sum of ecosystem in a geographical area

Question 3.
The adaptation of aquatic plants which roots are poorly developed is seen in
(a) Eichhornia
(b) Nymphaea
(c) Dunaliella
(d) Vallisneria
Ans.
(d) Vallisneria

Question 4.
Plenty of aerenchyma are found in
(a) hydrophytes
(b) mesophytes
(c) xerophytes
(d) halophytes
Ans.
(a) hydrophytes

Question 5.
The plant that does not belong to the ecological group, represented by the other plants is
(a) Pistia
(b) Casuarina
(c) Jussiaea
(d) Hydrilla
Ans.
(b) Casuarina

Question 6.
Sunken stomata are seen in
(a) hydrophytes
(b) xerophytes
(c) parasites
(d) symbionts
Ans.
(b) xerophytes

Question 1.
The organisms and their environment in a particular area
(a) bioregion
(b) biosphere
(c) ecosystem
(d) biome
Answer:
(c) ecosystem

Question 2.
Community is a group of independent and interacting population of
(a) different species
(b) same species
(c) same species in a specific area
(d) different species in a specific area
Answer:

Question 3.
Group of two or more than two plant species is called as
(a) plant community
(b) animal ecosystem
(c) plant ecosystem
(d) ecological niche
Answer:
(a) plant community

Question 4.
Which of the following is an animal of benthic zone?
(a) Frog
(b) Chemosynthetic bacteria
(c) Rat
(d) Human being
Answer:
(b) Chemosynthetic bacteria

Question 5.
Example of submerged hydrophyte is
(a) Hydrilla
(b) Lemna
(c) Nelumbium
(d) Eichhornia
Answer:
(a) Hydrilla

Question 6.
An association of two organism living together and benefitting each other is called ……….
(a) mutualism
(b) saprophytism
(c) parasitism
(d) commensalism
Answer:
(a) mutualism

Question 7.
A high density of tiger population is an area can result is
(a) predation
(b) interspecific competition
(c) intraspecific competition
(d) protocooperation
Answer:
(c) intraspecific competition

Question 8.
Which of the following shows detrimental effects on species
(a) mutualism
(b) predation
(c) parasitism
(d) competition
Answer:
(d) competition

Question 9.
Plasmodium is an example of
(a) predator
(b) endoparasite
(c) prey
(d) ectoparasite
Answer:
(b) ectoparasite

Question 10.
Monarch butterfly is not eaten by predators because of
(a) rough skin
(b) bitter taste
(c) foul smell
(d) colouration
Answer:
(b) bitter taste

Question 11.
The association of animals where both partners are benefitted is
(a) commensalism
(b) amensalism
(c) mutualism
(d) parasitism
Answer:
(c) mutualism

Question 12.
There are two optimal ways of exploitation one way is parasitism. Which is the other one?
(a) Antibiosis
(b) Competition
(c) Predation
(d) Commensatism
Answer:
(c) Predation

Question 13.
The most important factor which determined the increase in human population in India during 20th century is
(a) natality
(b) mortality
(c) immigration
(d) emigration
Answer:
(c) immigration

Question 14.
Population density is represented by
(a) N/S
(b) N/t
(c) t/S
(d) DNn/Dt
Answer:
(d) DNn/Dt

Question 15.
Natality increases the
(a) population density
(b) population size
(c) number of organisms in the population
(d) All of the above
Answer:
(d) All of the above

Fill in the blanks

Question 1.
Some xerophytes have multiple epidermis like …………. .
Answer:
Nerium

Question 2.
Leaves are large, broad and thin in …………. plants.
Answer:
mesophytic

Question 3.
Fish, amphibians and reptiles are ……………. .
Answer:
stenothermal animals

Question 4.
Root caps are present in ………….. .
Answer:
mesophytes

Question 5.
………. is the mechanism evolved by competing species for co-existence.
Answer:
Resource partitioning

Question 6.
Fig and wasp show ralationship.
Answer:
mutualistic

Correct the statements, if required by changing the underlined words

Question 1.
Plants which grow in bright light are called sciophytes.
Answer:
heliophytes

Question 2.
The organism which can tolerate a wide range of temperature are called stenothermal organisms.
Answer:
eurythermai

Question 3.
Plants growing in moist habitat are known as xerophytes.
Answer:
mesophytes

Question 4.
Plants growing in dry land are called mesophytes.
Answer:
xerophytes

Question 5.
Lichens represent an intimate mutualistic relationship between fungus and algae.
Answer:
It is correct

Question 6.
Mediterranean orchid ophrys employs sexual compatibility to get pollinated by bee.
Answer:
sexual deceit

Express in one or two words

Question 1.
The type of habitat in which plants are adapted to live in water scarcity.
Answer:
Xeric habitat.

Question 2.
The type of organisms who change their osmotic concentration according to the environment.
Answer:
Osmoconformers.

Question 3.
The factors which are related to soil in a habitat.
Answer:
Edaphic factors.

Question 4.
Plants growing or adapted to live in the shade.
Answer:
Sciophytes

Question 5.
Plants that grow best in direct sunlight.
Answer:
Heliophytes

Question 6.
The mechanism in which one animal kills other and eat it.
Answer:
Predation

Question 7.
The mechanism in which one species depend on the other for food and shelter.
Answer:
Parasitism

Short Answer Type Questions

Question 1.
Write different features of mesophytes.
Answer:
These are plants which grow in moist habitats and need well-aerated soils. These show the following characteristics

1. Root system is well-developed. They are branched, with root caps and root hairs.
2. Stems are aerial and freely branched.
3. Leaves are large, broad and thin.
4. Cuticle in all aerial parts is moderately developed.
5. The stomata are dorsiventral in dicotyledons and isobilateral position in monocot leaves.
6. The photosynthetic are in leaf, i.e., mesophyll tissue in differentiated into palisade, parenchyma and spongy parenchyma.
7. Water and food conductive tissue (vascular tissue) and mechanical tissue (collenchyma and sclerenchyma are well-developed.)

Question 2.
Write a note on hydrophytes.
Answer:
Hydrophytes
The plants growing in abundance of water or wet place are called hydrophytes. These plants may be partially or wholly submerged in water.
The aquatic habit at provides the following to the plant to grow

1. Availabity of nutrients in the water.
2. Plant growth matrix.
3. Approximate constant temperature (with least variation).
4. Availability of light.
5. Movement of water (waves strong or weak).

Based on the relation of plants to water and air.

Question 3.
Write short note on hydrophytic adaptations in roots of plants.
Answer:
Adaptations in hydrophytes can be discussed under three headings, i.e. morphological, anatomical and physiological.
1. Morphological Adaptations
Hydrophytes show various kinds of structural adaptations in their roots, stems and leaves.

• Roots may be entirely absent, e.g. Wolffia, Salvinia or poorly developed, e.g. Hydrilla.
• Roots are well-developed with distinct root caps, e.g. Ranunculus (emergent hydrophytes), aerenchyma present.
• In Eichhornia root caps are replaced by root pockets.
• Some plants, i.e. Jussiaea have two types of roots, one is normal type and other is spongy and negatively geotrophic.

Question 4.
What are free-floating and rooted hydrophytes?
Answer:
Free-floating hydrophytes These plants are absolutely float freely on the water surface and are not linked to the soil or substratum, e.g. Duck weed (Lemna and Wolffia), water hyacinth (Eichhomia crassipes), water ferns (Azolla and Salvinia).

Question 5.
What is habitat? Name some factors which define habitat of an organism.
Answer:
Habitat is a natural abode or a locality where a plant or animal grows or in other words, where a species lives.
The factors which define habitat can be climatic temperature, humidity, edaphic, i.e. related to soil, topographic or physical.

Question 6.
List various adaptations shown by epidermis in xerophytic plants.
Answer:
Physiologically dry habitats have plants of water, but the water is not available to the plant.
Based on their adaptation to water scarcity or drought conditions, xerophytes are of three types

1. Drought resistant plants are such that they can survive in extreme conditions, drought enduring plants can tolerate drought though they may hot have adaptation.
2. Drought enduring plants these do not have distinct adaptation.
3. Drought escaping plants these are short lived plants, complete the life cycle before the arrival of dry condition, e.g. Artemisia, Astragalus.

Question 7.
Does light factor affect the distribution of organisms? Write a brief note giving suitable examples of plants.
Answer:
Plants require sunlight for photosynthesis. Therefore, light is an important factor that affects the distribution of plants, e.g.

1. Many species of small plants (herbs and shrubs) growing in forests are adapted to photosynthesis optimally under very low light conditions so, they are seen distributed in shady areas under tall, canopied trees.
2. Many plants in the shade will grow vertically to gain access to light. These plants will appear to have smaller leafs than others of the same species of the , same age found in conditions with better sunlight.
3. Large sized trees will be present in areas that get abundant sunlight.

Question 8.
List any four characteristics that are employed in human population census.
Answer:
A population has the following characteristics that are employed in human population census

• Natality and mortality
• Sex-ratio
• Population density
• Age distribution

Question 9.
Describe the mutual relationship between the fig tree and wasp and comment on the phenomenon that operates in their relationship.
Answer:
The relationship between fig tree and wasp shows mutualism. The wasp while searching for sites to lay its eggs, pollinates the fig’s inflorescence.
On the other hand, the fig not only provides shelter (fruit) for oviposition, but also allows wasp’s larva to feed on its seeds.

Question 10.
What is mutualism? Mention any two examples where the organisms involved are commercially (2018) exploited in agriculture.
Answer:
It is an interaction that confers benefits to both the interacting species. Some examples of mutualism are

1. Lichens represent an intimate mutualistic relationship between a fungus (mycobiont) and photosynthesising algae (phycobiont) or cyanobacteria. Here, the fungus helps in the absorption of nutrients and provides protection, while algae prepares the food.
2. Mycorrhiza show dose mutual association between fungi and the roots of higher plants. Fungi help the plant in absorption of nutrients, while the plant provides food for the fungus, e.g. many members of genus -Glomus.
3. Plants need help from animals for pollination and dispersal of seeds. In return, plants provide nectar, pollens and fruits to them

Question 11.
Name important defence mechanisms in plants against herbivory.
Answer:
The herbivores are predators of plants and nearly 25% insects are phytophagous (feeding on plants). So, plants show morphological as well as chemical defence against herbivores such as

1. Thorns of rose and Acacia as well as cactus.
2. Certain plants produce chemicals, such as Opium, quinine, caffeine, nicotine, to protect them against being grazed by the animals.
3. Calotropis produces highly poisonous cardiac glycosides. So, the cattle and goats do not eat this plant.

Question 12.
What is predation? Explain with the help of suitable examples why is it required in a community with rich biodiversity.
Answer:
Predation is an interaction where one organisms (predator) kills and eats the other weaker organisms called prey.
Predation is a natural way of transferring the energy fixed by plants, to higher trophic levels.
Examples-snake eating a frog, tiger killing and eating a deer. Predators keep prey population under control which otherwise could achieve very high population densities and cause instability in ecosystem.
They also help in maintaining a species diversity in a community by reducing. The intensity of competition among competing prey species.

Question 13.
Name the interaction in each of the following:
(i) Cuckoo lays her eggs in the crow’s nest.
(ii) Orchid grows on a mango tree.
(iii) Ticks live on the skin of dogs.
Answer:
(i) Brood parasitism.
(ii) Commensalism, orchid is an epiphyte.
(iii) Parasitism, ticks are ectoparasites.

Question 14.
Explain the S-shaped pattern of population growth. How is J-shaped pattern different from it and why?
Answer:
S-shaped pattern of population growth form shows an initial gradual increase, followed by an exponential increase and then a gradual decline to a near constant level. It is different from J-shaped curve because J-shaped pattern shows exponential population growth and its abrupt crash after attaining the peak value. A-When resources are not limiting the growth, plot is exponential. B-When resources are limiting the growth, plot is logistic, K is the carrying capacity.

Question 15.
Explain diagrammatically the age structure of expanding, stable and declining population.
Answer:
The pyramids can be of three difference types as follows
1. Expanding (Triangular) This is a type of a growing population representation is like a triangle.
The population carries a high proportion of pre-reproductive individuals followed by reproductive individuals and post-reproductive individuals. Because of the very large number of pre-reproductive individuals, more and more of them enter reproductive phases and rapidily increases the size of the population.

2. Stable (Bell-shaped) This type of pyramid will represent a stationary or stable population having an equal number of young and middle aged class of individiuals.

3. Declining (Urn-shaped) This group has a small number of pre-reproductive individuals followed by a large number of reproductive individuals. As, there is less number of individuals in pre-reproductive groups.

Differentiate between the following (for complete chapter)

Question 1.
Population and Community.
Answer:
Differences between population and community are as follows

Population	Community
It is a grouping of individuals of a single species found in an area.	It is grouping of individuals of different species found in an area.
All the individuals of a population are morphologically and behaviourly similar.	Different members of a community are morphologically and behaviourly dissimilar.
Individuals of a population interbreed freely.	Interbreeding is absent amongst different members of a community.

Question 2.
Mesophytes and Hydrophytes.
Answer:
Differences between mesophytes and hydrophytes are as follows

Mesophytes	Hydrophytes
The plants grown on terrestrial habitate (land).	These are found in aquatic habitate (water).
The root septum is very cell developed in there plants.	Root system is not very well-developed or absent.
Leaves are broad, large and thin, mucilage covering is absent.	Leaves are, thin ribbon-shaped and covered with mucilage.

Question 3.
Mutualism and Commensalism.
Differences between mutualism and commensalism are as follows

Mutualism	Commensalism
In this two species are involved, both derive benefit from each other.	Two species involved but only one ge{ benefit other remain unharmed.
Example-see-anemone and hermit-crab.	Example-Sucker fish and shark.

Question 4.
Parasitism and Predation.
Answer:
Differences between parasitism and predation are as follows

Parasitism	Predation
It is host specific.	Predators have choice of prey.
Parasites are smaller is size.	Predators are large in size.
These have high reproductive potential.	These have low reproductive potential.

Question 5.
Ectoparasites and Endoparasites.
Answer:
Differences between ectoparasites and endoparasites are as follows

Ectoparasites	Endoparasites
Ectoparasites live on the surface of the host.	Endoparasites live in the body of the host.
They can be temporary, intermittent or permanent.	They are generally permanent parasites.
They can be hemiparasites or holoparasites.	They are usually holoparasites.
Respiration is aerobic.	Respiration is ofter anaerobic.
Specialisation has lead to loss of fewer strutures, e.g. wings in fleas, bedbugs and lice.	Specialisation has led the loss of several structures, e.g, digestive organs in Taenia.

Question 6.
Immigration and Emigration.
Answer:
Differences between immigration and emigration are as follows

Immigration	Emigration
It is permanent inward movement of some individuals into a local population.	It is a permanent outward movement of some individuals from a local population.
Size of gene pool and local population in increases.	Size of gene pool and local population decreases.
It is caused by availability of better living conditions.	It is caused by occurrence of deficiencies and calamities.

Question 7.
Camouflage and Mimicry.
Answer:
Differences between camouflage and mimicry are as follows

Camouflage	Mimicry
It is the ability of animals to blend with the background.	It is resemblance of on species of animals with another species.
Camouflage allows the animals to remain unnoticec from a distance.	Mimicry hides the true 1 identity of the animal species.
It is advantageous to both prey as well as predator.	It is advantageous to mimics against predation.

Question 8.
Intraspecific competition and Interspecific competition.
Answer:
Differences between intraspecific competition and interspecific competition are as follows

Intraspecific competition	Interspecific competition
It is competition among individuals of the same species.	The competition is amongst the members of different species.
The competition is for all the requirements.	The competition is for one or a few requirements.
The competing individuals have similar type of adaptation.	The competing individuals have different types of adaptations.
It is more severe due to similar needs and adaptations.	It is less severe as the similar needs are a few and the adaptations are different.

Odisha State Board CHSE Odisha Class 12 Biology Important Questions Chapter 13 Applications of Biotechnology Important Questions and Answers.

CHSE Odisha 12th Class Biology Important Questions Chapter 13 Applications of Biotechnology

Applications of Biotechnology Class 12 Important Questions CHSE Odisha

Very Short Answer Type Questions

Choose the correct option

Question 1.
A biotech company that released first ever genetically manipulated flower into the market is
(a) Cryobank
(b) Eli Lilly
(c) Florigene
(d) Genentech
Ans.
(c) Florigene

Question 2.
When an abnormal gene is replaced by normal gene, what do you call it? (2023)
(a) Gene mutation
(b) Gene donning
(c) Gene therapy
(d) Gene ligation
Ans.
(c) Gene therapy

Question 3.
Cry II Ab and Cry I Ab produce toxins that control
(a) cotton bollworms and corn borer, respectively
(b) corn borer and cotton bollworms, respectively
(c) tobacco budworms and nematodes, respectively
(d) nematodes and tobacco budworms, respectively
Ans.
(a) cotton bollworms and corn borer, respectively

Question 4.
First genetically modified plant commercially released in India is
(a) golden rice
(b) slow ripening tomatoes
(c) Bt-bringal
(d) Bt-cotton
Ans.
(d) Bt-cotton

Question 5.
Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because
(a) bacteria are resistant to the toxin
(b) toxin is immature
(c) toxin is inactive
(d) bacteria enclose toxin in a special sac
Answer:
(c) toxin is inactive

Question 6.
Basic principle of developing transgenic animals is to introduce the gene of interest into the nucleus of
(a) somatic cell
(b) vegetative cell
(c) germ cell
(d) body cell
Answer:
(c) germ cell

Question 7.
Which among the following pharmaceutical products is harvested by using transgenic animals as bioreactors?
(a) Urokinase
(b) Insulin
(c) Lactoferrin
(d) All of these
Answer:
(d) All of these

Question 8.
The superbug can be used in
(a) oil spills
(b) water pollution
(c) eutrophication
(d) air pollution
Answer:
(a) oil spills

Question 9.
Biopatents are usually awarded for the discovery of
(a) new cell lines
(b) new DNA sequences
(c) GM strains
(d) All of these
Answer:
(d) All of these

Question 10.
Exploitation of patent biological resources of a country by another country is known as?
(a) biopatent
(b) biopiracy
(c) biowar
(d) All of these
Answer:
(b) biopiracy

Question 11.
Patents are given for
(a) discoveries
(b) inventions
(c) biopiracy
(d) gene therapy
Answer:
(b) inventions

Questions 12.
Which one of the following known as ‘Superbug’?
(a) Pseudomonas putida
(b) E. coli
(c) Aspergillus niger
(d) Acetobacter aceti
Answer:
(a) Pseudomonas putida

Questions 13.
US Patent on turmeric was challanged by
(a) CSIR
(b) EPO
(c) FSSAI
(d) FDI
Answer:
(a) CSIR

Questions 14.
Biopiracy is
(a) the use of biological patent
(b) thefts of plants and animals
(c) the use of bioresources of a country without proper authorisation
(d) stealing of biological resources
Answer:
(c) the use of bioresources of a country without proper authorisation

Correct the statements, if required, by changing the underlined words

Question 1.
An amorphous mass of parenchyma cells developed by tissue culture is called embryo.
Answer:
Callus

Question 2.
Petunia is ice minus strain which when sprayed on crops prevents frost formation.
Answer:
Pseudomonas

Question 3.
The natural source of vitamin-E is α-tocopherol.
Answer:
γ-tocopherol

Question 4.
The first GMO was created by Watson.
Answer:
Herbert Boyer and Stanley Cohen.

Question 5.
Soil bacterium Nitrosomonas syringae promotes ice nucleation in plants.
Answer:
Pseudomonas

Question 6.
The C-peptide is added during the maturation of pro-insulin to insulin.
Answer:
deleted

Question 7.
ADA treatment uses monocytes.
Answer:
lymphocytes

Question 8.
Antitrypsin is an agent that dissolves blood clot.
Answer:
Tissue Plasminogen Activator (TPA).

Question 9.
The first transgenic cow was Lilly.
Answer:
Rosie

Question 10.
A Pacific transgenic whale was generated by a growth hormone transgene.
Answer:
salmon

Question 11.
Transgenic mouse is smaller than the normal mouse.
Answer:
larger

Question 12.
Human protein α-2-trypin is used to treat emphysema.
Answer:
α-1-antitrypsin

Express in one or two word(s)

Question 1.
Define callus.
Answer:
It is undifferentiated mass of totipotent cells in the culture media.

Question 2.
Name one plant used to create novel transgenic plants.
Answer:
Petunia

Question 3.
Name the drugs isolated from Catharanthus roseus for cancer treatment.
Answer:
Vincristine and vinblastine.

Question 4.
Which microorganism is used as cloning host cell to produce humulin?
Answer:
E. coli

Question 5.
State the number of polypeptides found in mature human insulin.
Answer:
Two

Question 6.
What do you mean by the term transgene?
Answer:
oreign gene that is incorporated in an orgainsm to bring about desirable changes.

Question 7.
Where the LDL receptors are present?
Answer:
On the surface of hepatocytes

Question 8.
What is the name of the scientist who coined a sheep named Dolly?
Answer:
Keith Campbel and Ian Wilmut.

Question 9.
Name the institute that came up with a cloned sheep, named Dolly.
Answer:
Ian Wilmut of Roslin Institute in Scottland.

Question 10.
Which department of the Goverment of India is the nodal centre for Indian biosafety network?
Answer:
Department of biotechnology.

Question 11.
Which bacterium species is involved in Diamond vs Chakraborty case?
Answer:
Pseudomonas

Question 12.
What are transgenic animals?
Answer:
Genetically modified organism

Question 13.
Name the first transgenic cow that produced human protein enriched milk.
Answer:
Rosie

Question 14.
Name a transgenic animal being used in testing the safety of polio vaccine.
Answer:
Mouse

Question 15.
Mention the name of two common diseases that can be treated by medicines that contain biological products of transgenic animals.
Answer:
Cystic fibrosis and rheumatoid arthritis

Question 16.
What is patent?
Answer:
It is an open latter, a set of legal right, privilege and authority granted by a sovereign state to a person or institution for an invention for a limited period of time.

Fill in the blanks

Question 1.
…………… is a mammalian protein that have been successfully expressed in plants.
Answer:
Enkephalin.

Question 2.
Genetically engineered rice rich in vitamin-A is known as ……………… .
Answer:
golden rice

Question 3.
The recombinant human insulin is known as …………. .
Answer:
humulin

Question 4.
The full form of ELISA is ………… .
Answer:
Enzyme Linked Immunosorbant Assay.

Question 5.
Primarily, insulin is synthesised as ……………. .
Answer:
single polypeptide.

Question 6.
SCID is caused due to failure of synthesis of enzyme ………….. .
Answer:
adenosine deaminase.

Question 7.
…………. is the precursor of vitamin-A.
Answer:
ß-carotene

Question 8.
………… infects the roots of tobacco plants.
Answer:
Agrobacterium

Question 9.
The transgenic mouse is called as …………….. .
Answer:
Super mouse

Question 10.
…………. is a transgenic sheep.
Answer
Dolly

Question 11.
…………. is an infant nutrition formula that have been harvested using transgenic animals as bioreactors.
Answer:
Lactoferrin.

Question 12.
In 1990 ……….. the transgenic ewe was born in Scottland.
Answer:
Tracy

Question 13.
Full from of TPA is ……………. .
Answer:
Tissue Plasminogen Activator.

Question 14.
Neem patent case was first awarded in favour of ……………. .
Answer:
USA.

Short Answer Type Questions

Question 1.
Find out from the internet what is golden rice.
Answer:
Golden rice is a genetically modified rice with high levels of ß-carotene and other carotenoids. This rice is modified in order to enhance the quantity of vitamin-A in it. It is called golden due to the gold-like colour it gets from ß-carotene.

Question 2.
Can a disease be detected before its symptoms appear? Explain the principle involved.
Answer:
When the symptoms of the disease are not visible and the pathogen concentration is very low, then detection by conventional diagnostic tests is very difficult. However, detection at the above stated stage is made possible by molecular diagnostic techniques like the amplification of their nucleic acid by Polymerase Chain Reaction (PCR). The principle involved here is that a single DNA molecule can be copied endlessly in a test tube, using primers, DNA polymerase enzyme and free nucleotides and appropriate conditions.

Question 3.
How is DNA recombinant technology helpful in detecting the presence of mutated genes in the cancer patients?
Answer:
Molecular diagnosis in DNA recombinant technology uses a single-stranded DNA or RNA tagged with a radioactive molecules. It is allowed to hybridise to its complementary DNA in a clone of cells followed by detection using autoradiography. The clone having the mutated gene will not appear on the photographic film, because the probe used will not be complementary to the mutated gene. In this way, presence of mutated genes can be detected.

Question 4.
Why is the functional insulin produced, considered better than the ones used earlier by diabetic patients?
Answer:
Insulin prepared by rDNA technology does not produce sensitive allergic reactions and complications to the foreign protein which occurred in the case of earlier extracted insulin from the pancreas of slaughtered cattle or pigs. Thus, it is considered better than the earlier used insulin.

Question 5.
How is a mature, functional insulin hormone different from its pro-hormone form?
Answer:
Mature functional insulin is obtained by the processing of pro-hormone which contains extra peptide called C-peptide. This C-peptide is removed during the maturation of pro-insulin to insulin.

Question 6.
Refer to the diagram given below and answer the questions that follows

(i) The diagram shown above is insulin or proinsulin? Justify.
(ii) How is mature insulin synthesised?
Answer:
(i) The diagram is proinsulin as it contains C-peptide.
(ii) Mature insulin is synthesised by the removal of extra stretch called C-peptide.

Question 7.
How did an American Company, Eli Lilly use the knowledge of rDNA technology to produce human insulin?
Or
How did Eli Lilly synthesise the human insulin? Mention one difference between this insulin and the one produced by the human pancreas.
Or
What is humulin?
Answer:
The production cost was high due to its complex extraction and purification processes. Additionally, the purified insulin was contaminated by many pathogenic viruses. These problems have been overcome by the use of recombinant DNA technology. Insulin that is produced by recombinant DNA technology is known as recombinant human insulin.

Question 8.
Recombinant DNA technology is of great
importance in the field of medicine. With the help of a flow chart, show how this technology has been used in preparing genetically engineered human insulins.
Answer:
Insulin production by using recombinant DNA technology is shown in flow chart below

Question 9.
What is gene therapy? Name the first clinical case in which it was used.
Or
What is gene therapy? Illustrate using the example of Adenosine Deaminase (ADA) deficiency.
Answer:
It is a method of treatment which allows correction of a biochemical (like phenylketonuria) or a genetic defect*that has been diagnosed in a child or embryo. The defective mutant alleles of the gene are replaced by the normal gene insertion to take over the function of and compensate for the non-functional gene. Gene therapy is widely used to treat

• Biochemical disorder, e.g. alkaptonuria, phenylketonuria, albinism, etc.
• Chromosomal and gene disorders, e.g. Down’s syndrome, Turner’s, syndrome, Klinefelter’s syndrome, fragile X-syndrome, cri-du chat, Huntington’s disease, Tay-Sach’s syndrome, etc.

Question 10.
Write a note on genetically modified organism.
Answer:
The plants, bacteria, fungi and animals whose genes have been altered by manipulation are called Genetically Modified Organisms (GMO).
These are also called transgenic organisms, as they contain and express one or more foreign genes called transgenes. Herbert Boyer and Stanley Cohen developed the first GMO in 1973.

They transferred the Kanamycin antibiotic resistance gene of a bacterium into the another Kanamycin sensitive bacterium.
The genes which are being transferred are called transgenes.
The recepient bacterium later acquired Kanamycin resistance. Following many such discoveries, GMOs were developed. Novel plants and animals were created by genetic manipulation for human welfare.

Question 11.
Write a short note on transgenic plants.
Answer:
Herbicide resistant plants Herbicide resistant transgenic plants are generated by transferring bacterial herbicide resistant genes into plant cells grown in culture. Glyphosate is the most widely used broad-spectrum herbicide world over.

A glyphosate resistant gene from Petunia plant is transferred into isolated plant cell§ in culture and glyphosate resistant plants are generated.

Question 12.
Write a short note with 2-3 important points on Bacillus thuringiensis.
Or
Why do the toxic insecticide proteins secreted by Bacillus thuringiensis kill insects?
Answer:
Bacillus thuringiensis (Bt) It is a soil-borne, Gram-positive bacterium. It is used to create transgenic plants having resistance to different pests. The genes having insecticidal properties in the bacterium are isolated and incorporated into plants by using advanced biotechnological methods to create Bt plants. During sporulation, many Bt strains produce crystal proteins (proteinaceous inclusions) called S-endotoxins, that have insecticidal action.

When consumed by insect, these toxins bind to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis, leading to the death of an insect, e.g. 5r-cotton, fir-tomato, soybean, coffee, etc.

Question 13.
Why does Bt toxin cannot kill the bacterium that produces it, but kills the insect that ingests it?
Answer:
Bt toxin is produced by a soil bacterium called Bacillus thuringiensis. This toxin does not kill the bacterium which produces it, because in them, it is present in an inactive and crystalline form. It becomes active and toxic only when it is consumed by insects such as lepidopterans, etc. due to the alkaline pH of the gut.

Question 14.
Bt cotton is resistant to pests, such as lepidopterans, dipterans and coleopterans. Is Bt cotton resistant to other pests as well?
Answer:
Bt cotton is made resistant only to certain specific taxa of pests. It is quite likely that in future some other pests may infest this Bt cotton. It is similar to immunisation against smallpox which does not provide immunity against other pathogens like those that cause cholera, typhoid, etc.

Question 15.
Why certain cotton plants are called Bt cotton?
Answer:
Cotton plants are called Bt cotton because they bear specific Bt toxin genes which were isolated from Bacillus thuringiensis and incorporated into certain cotton plants. This helps the host plants in developing resistance against and various pests like bollworms, etc.

Question 16.
Differentiate the terms ‘Cry’ and ‘cry’.
Answer:
‘Cry’ refers to protein symbol and its first letter is always capital. It is written in Roman letters, ‘cry’ refers to the gene which is usually written in small letters and is invariably in italics.

Question 17.
What are Cry proteins? Name an organism that produces it. How has man exploited this protein to his benefit?
Or
Name the source and type of cry genes used for incorporation into crops by biotechnologists. Explain, how have these genes brought beneficial changes in the genetically modified crops.
Answer:
The proteins encoded by the gene named cry are called Cry proteins. Organism that produces Cry proteins is Bacillus thuringiensis.
The cry genes are incorporated in several crop plants, which then develop resistance to a specific targeted pest, e.g. cry IAc and cry IIAb control the cotton bollworms and cry LAb controls corn borer.

Question 18.
Expand GMO. How is it different from a hybrid?
Answer:
GMO stands for Genetically Modified Organism.
It differs from a hybrid because in a hybrid, cross is done between total genomes of two species or strains, whereas in a GMO, foreign genes from entirely dilferent species are introduced in the organism and are usually maintained as extrachromosomal entity or are integrated into the genome of the organism.

Question 19.
Describe any three potential applications of genetically modified plants.
Answer:
Potential applications of genetically modified plants are

• Nutritional enhancement, e.g vitamin-A enriched rice.
• Stress tolerance crops are more tolerant to abiotic stresses such as cold, drought, etc.
• Creation of tailor made plants by using GM plants to supply alternative resources to industries in the form of starches, biofuels, etc.

Question 20.
What is meant by transgenic animals?
Answer:
Animals that have had their DNA manipulated to possess and express an extra (foreign) gene are known as transgenic animals, e.g. transgenic rats, rabbits, pigs, sheep, cows and fish. Over 95% of all the existing transgenic animals are mice. The gene that is being transferred is called transgene.

Question 21.
Comment on how transgenic animals have proved to be beneficial in
(i) Production of biological products?
(ii) Chemical safety testing?
Answer:
(i) The transgenic animals have been proved to be beneficial in the production of biological products like human protein α-1 antitrypsin (by coding genes from that protein only), in the treatment of emphysema and production of human protein (α-lactalbumin) enriched milk by transgenic cow, i.e. Rosie. This milk was more nutritionally balanced for human beings than natural cow’s milk.
(ii) Transgenic animals are studied for testing toxicity of drugs and other chemicals as they carry genes that make them more sensitive to toxic substances.

Question 22.
What is the utility of transgenic animals?
Or
With respect to understanding diseases, discuss the importance of transgenic animal models.
Answer:
Transgenic animals are important in the following fields
(i) They are being used in basic science research to elucidate the role of genes in the development of diseases like cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s disease.
(ii) They are valuable tools in the drug development process itself.
(iii) Milk producing transgenics can produce medicines or human proteins (insulin, growth hormone, etc.) in large quantities.
(iv) Transgenics can be a source of transplant organs as well.

Question 23.
(i) Which animals are being used for testing the safety of vaccines? Name the vaccine for which trials are going on.
(ii) Name the first transgenic cow. Why is it important?
Answer:
(i) Transgenic mice are used for testing the safety of vaccines.
The trials are going on for polio vaccine.
(ii) Rosie was the first transgenic cow. It is important because it produces human protein enriched milk, even better than a natural cow’s milk.

Question 24.
(i) Explain alpha lactalbumin. Where is it produced in human body?
(ii) In what manner biotechnology has helped in production of more nutritionally balanced milk?
Answer:
(i) Alpha lactalbumin is a human milk protein which helps to increase the production of lactose in the body. It is produced in human milk.
(ii) Biotechnology has lead to production of transgenic cow, Rosie that produced around 2.4 g/L human protein enriched milk. This milk contained the human alpha lactalbumin and was nutritionally more balanced than a natural cow’s milk.

Question 25.
While creating genetically modified organisms, genetic barriers are not respected. How can this be dangerous in the long run?
Answer:
Genetic modification of organisms can have unpredictable results when such organisms are introduced into the ecosystem. Because the real effects of gene manipulation are visible only when such organisms interact with other components and organisms of the ecosystem.

Question 26.
Biopiracy should be prevented. State why and how?
Answer:
Biopiracy should he prevented because
(i) The countries and people concerned are not given adequate compensatory payment.
(ii) The countries/people also lose their right to grow and use breeding experiments to improve the other varieties of the same species.
It may be prevented by implementing specific laws that takes into consideration all the biopatents and biopiracy related issues.

Question 27.
State the initiative taken by the Indian Parliament against biopiracy.
Answer:
The Indian Parliament has recently passed the second amendment to the Indian Patents Bill that takes action against biopiracy. In India, the Patent Act was enacted in 1970 to protect their resources and traditional knowledge from being exploited by other countries.
This act has undergone many amendments in 1999, 2002, 2005 and 2006. The Indian biosafety network is headed by the Department of Biotechnology.

Question 28.
Write a self-explanatory note on biopatent.
Or What is patent?
Answer:
When an individual develops a new product or process innovation using his intellect, the innovation becomes his own. Various rules at national and international lands protects the misuse of this innovation, and also safeguards the rights of the innovater.
The new inventions can be safe protected by patents, design trademark, trade secrets and copy rights, etc.

It is a set of exclusive legal rights granted by a government to the inventors or their assignee for a limited period of time to prevent others from commercial use of their invention. When patent is granted for biological entities and for products derived from them, they are called biopatents. Primarily USA, Japan and members of European Union are awarding biopatents.

Question 29.
Name a set of principles that may be used to regulate human activities in relation to the biological world. Why are they important?
Answer:
A set of principles that may be used to regulate human activities in relation to the biological world are called bioethics.
These are important because the genetic modification of an organism can have unpredictable results when such organisms are introduced into the ecosystem.

Question 30.
What is meant by biopiracy?
Answer:
It refers to the use of bioresources by multinational companies and other organisations without proper authorisation from the countries and people concerned without compensatory payment. The majority of industrialised nations are financially rich but poor in biodiversity and traditional knowledge, in comparison to developing and underdeveloped countries.

Another cause of biopiracy is bioprospecting which means a thorough survey of a source material to expand the knowledge and applications in biotechnology. During the course of bioprospecting, scientists may transfer any biological resource which they may consider as novel.

Differentiate between the following (for complete chapter)

Question 1.
Herbicide resistant plants and Frost resistant plants.
Answer:
Differences between herbicide resistant plants and frost resistant plants are as follows

Herbicide resistant plants	Frost resistant plants
Generated by transferring bacterial herbicide resistant gene into plant cells.	Generated by deleting a gene that promotes ice nucleation.
e.g. Petunia contains glyphosate resistant gene which is being isolated to generate glyphosate resistant plants.	e.g. Pseudomonas syringae contains gene promoting ice nucleation. It is deleted by genetic engineering to produce ice minus strain.

Question 2.
Humulin and Wosulin.
Answer:
Differences between humulin and wosulin are as follows

Humulin	Wosulin
Manufactured by Eli Lilly corporation, USA.	Manufactured by wokhardt limited India.
First recombinant drug approved by FDA for human use.	General drug to treat diabetes.

Question 3.
Ex vivo gene therapy and In vivo gene therapy.
Answer:
Differences between Ex vivo gene therapy and In vivo gene therapy are as follows.

Ex vivo gene therapy	In vivo gene therapy
The cells are removed from the patient and genetic material is inserted in them in vitro, prior to transplantation of modified cells.	The genetic material is transferred directly into cells within a patient.
This approach is applicable to tissues that can be removed from the body and returned later and survive for longer period of time, e.g. hematopoietic cells.	It is only possible in tissues where the individual cells cannot be cultured in vitro in sufficient numbers or where cultured cells cannot be efficiently reimplanted, e.g. brain cells.

Odisha State Board CHSE Odisha Class 12 Biology Important Questions Chapter 12 Principles and Processes of Biotechnology Important Questions and Answers.

CHSE Odisha 12th Class Biology Important Questions Chapter 12 Principles and Processes of Biotechnology

Principles and Processes of Biotechnology Class 12 Important Questions CHSE Odisha

Very Short Answer Type Questions

Choose the correct option

Question 1.
GAATTC is the recognition site for which of the following restriction endonucleases?
(a) Hind III
(b) Eco RI
(c) Bam I
(d) Hae III
Answer:
(b) Eco RI

Question 2.
Given below is a sample of a portion of DNA strand giving the base sequence on the opposite strands. What is so special shown in it?
(a) Replication completed
(b) Deletion mutation
(c) Start codon at the 5′ end
(d) Palindromic sequence
Answer:
(d) Palindromic sequence

Question 3.
Agarose extracted from sea weeds is used in
(a) spectrophotometer
(b) tissue culture
(c) PCR
(d) gel electrophoresis
Answer:
(d) gel electrophoresis

Question 4.
The blotting of RNA is called
(a) Northern blot
(b) Southern blot
(c) Western blot
(d) Eastern blot
Answer:
(a) Northern blot

Question 5.
Eco RI cleaves the DNA strands to produce
(a) blunt ends
(b) sticky ends
(c) satellite ends
(d) ori replication end
Answer:
(b) sticky ends

Question 6.
DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by
(a) electrophoresis
(b) restriction mapping
(c) centrifugation
(d) polymerase chain reaction
Answer:
(a) electrophoresis

Question 7.
Commonly used vectors for human genome sequencing are
(a) T-DNA
(b) BAC and YAC
(c) expression vector
(d) T/A cloning vectors
Answer:
(b) BAC and YAC

Question 8.
Which procedure is followed for amplification of DNA?
(a) Electrophoresis
(b) Autoradiography
(c) Polymerase chain reaction
(d) Southern blotting
Answer:
(c) Polymerase chain reaction

Question 9.
The Polymerase Chain Reaction (PCR) is a technique that is used for
(a) in vivo replication of specific DNA sequence using thermostable DNA polymerase
(b) in vitro synthesis of mRNA
(c) in vitro replication of specific DNA sequence using thermostable DNA polymerase
(d) in-vivo synthesis of mRNA
Answer:
(c) In-vitro replication of specific DNA sequence using thermostable DNA polymerase.

Question 10.
The figure below shows three steps (A, B, C) of Polymerase Chain Reaction (PCR). Select the option giving correct identification together with what it represents?

(a) B – denaturation at a temperature of about 98°C separating the two DNA strands
(b) A – denaturation at a temperature of about 50°C
(c) C – extension in the presence of heat stable DNA polymerase
(d) A – annealing with two sets of primers
Answer:
(a) B – denaturation at a temperature of about 98°C separating the two DNA strands.

Question 11.
In recombinant DNA technique, the term vector refers to
(a) plasmids that can transfer foreign DNA into a living cell
(b) cosmids that can cut DNA at specific base sequence
(c) plasmids that can join different DNA fragments
(d) cosmids that can degrade harmful proteins
Answer:
(a) plasmids that can transfer foreign DNA into a living cell

Question 12.
The rDNA molecule is introduced into the cell of bacterium with the help of.
(a) restriction endonuclease
(b) DNA ligase
(c) electroporation
(d) None of the above
Answer:
(a) restriction endonuclease

Question 13.
The bacterial source of Hpa I is
(a) Haemophilus influenzae
(b) Bacillus amyloliquefaciens
(c) Providentcia stuarth
(d) Haemophilus parainfluenzae
Answer:
(d) Haemophilus parainfluenzae

Question 14.
Klenow fragment does not possess
(a) 5′ → 3′ exonuclease
(b) 3′ → 5′ exonuclease
(c) polymerase
(d) All of the above
Answer:
(a) 5′ → 3′ exonuclease

Correct the statements, if required, by changing the underlined word(s)

Question 1.
Restriction enzymes are used to cut single-stranded DNA.
Answer:
double-stranded DNA.

Question 2.
‘CO’ part in Eco RI stands for coenzyme.
Answer:
coli.

Question 4.
The first isolated restriction endonuclease was Hind III.
Answer:
Eco RI

Question 5.
DNA ligase forms phosphodiester bonds to ligate the DNA fragments.
Answer:
It is correct

Question 6.
Plasmids present in bacterial cells are linear double helical DNA molecules.
Answer:
circular

Question 7.
Taq polymerase is used between annealing and denaturation during PCR.
Answer:
extension.

Question 8.
A hybrid of plasmid and phage is YAC.
Answer:
BAC

Question 9.
Bacteria phage are autonomously replicating circular DNA.
Answer:
Bacteriophage

Fill in the blanks

Question 1.
DNA polymerase can be obtained from ……….. .
Answer:
Thermus aquaticus

Question 2.
The usual source of restriction endonuclease used in gene cloning is ………….. .
Answer:
bacteria .

Question 3.
Other than E. coli ………….. bacteria is used in recombinant DNA technology.
Answer:
Salmonella typhimurium.

Question 4.
First letter of restriction enzymes represents …………. .
Answer:
genus

Question 5.
Alkaline phosphatase is ………. an enzyme.
Answer:
DNA ligase

Question 6.
The vector for T-DNA is ………….. .
Answer:
Agrobacterium tumefaciens.

Question 7.
In biolistic method ………….. particles coated with foreign DNA are bombarded into target cells.
Answer:
gold or tungesten.

Question 8.
……………. is most commonly used process of foreign DNA injection in animal cells.
Answer:
Microinjection

Question 9.
…………. helps in selecting transformants and eliminating non-transformants.
Answer:
Conventional method

Express in one or two word(s)

Question 1.
Molecular scissors used in recombinant technology are known as
Answer:
restriction enzymes.

Question 2.
Which enzyme helps in joining DNA fragments?
Answer:
DNA ligase.

Question 3.
Name the process of transfer of protein molecules onto a membrane.
Answer:
Western blotting

Question 4.
Single-stranded fragments are transferred onto nitrocellulose filter paper by which process?
Answer:
Northern blotting

Question 5.
Name the bacterium that yields thermostable DNA polymerases.
Answer:
Thermus aquaticus

Question 6.
What is particle gun?
Answer:
It is a technique of bombarding microparticles of gold or tungsten with foreign DNA into target cell with high velocity.

Question 7.
Name one chemical that helps foreign DNA to enter host cell.
Answer:
Transformation

Short Answer Type Questions

Question 1.
Write a short note on genetic engineering.
Answer:
Genetic engineering is a modification, of chemical nature of genetic material (DNA/RNA) and their introduction into another organism to change the phenotypic characters of that organism.
This involves recombinant nucleic acid (DNA or RNA) techniques to form new combinations of heritable genetic material followed by the incorporation of material indirecdy through vectors or directly through microinjection and other techniques.

Question 2.
What are restriction enzymes? Mention their functions in recombinant DNA technology.
Answer:
The enzymes used for cutting the DNA during recombinant DNA technology are called restriction enzymes.
Restriction enzymes function as chemical knives or molecular scissors in genetic engineering. It recognises specific nucleotide sequence and makes cuts.

Question 3.
(i) Mention the difference in the mode of action of exonuclease and endonuclease.
(ii) How does restriction endonuclease function?
Answer:
(i) Exonucleases cleave base pairs of DNA at their terminal ends (either 5′ or 3 0 while, the endonucleases cleave DNA at any point within DNA segment at specific position except terminal ends.

(ii) Restriction endonuclease Eco RI cuts the DNA strands a little away from the palindromic sequences, but between the same two bases on the two strands

Question 4.
How are ‘sticky ends’ formed on a DNA strand? Why are they so called?
Or
A recombinant DNA is formed when sticky ends of the vector DNA and the foreign DNA join. Explain how sticky ends are formed and get joined?
Answer:
Restriction enzymes cut the strands of the DNA, a little away from the centre of the palindromic sites, but between the same two bases on opposite strands. This leaves sticky single-stranded position at the ends. These overhanging stretches are called ‘sticky ends’. These are named so, because they form hydrogen bonds with their complementary cut counterparts.

Question 5.
What does Hind and ‘III’ refer to in the enzyme Hind III?
Answer:

1. The first letter ‘H indicates the genus of the organism, from which the enzyme was isolated, i.e. H-genus, Haemophilus.
2. The roman number (III) denotes the sequence in which the restriction endonuclease from that particular genus, species and strain of bacteria have been isolated, i. e., third restriction endonuclease to be isolated from this species.

Question 6.
Collect five examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following base pair rules.
Answer:

Question 7.
Restriction enzymes should not have more than one site of action in the cloning site of a vector. Comment.
Answer:
Enzymes should not have more than one site of action.
This is because vectors have very few recognition sites for commonly used restriction enzymes.
If it will have more than one restriction sites it will generate various fragments. This will complicate the process of genetic engineering.

Question 8.
Draw agarose gel electrophoresis apparatus. Description is not required.
Answer:

(a) Agarose gel apparatus, (b) Fluorescent bands on the agarose gel slab containing resolved DNA fragments with differing molecular weights.

Question 9.
A mixture of fragmented DNA was electrophoresed in an agarose gel. After staining the gel with ethidium bromide, no DNA bands were observed. What could be the reason?
Answer:
DNA bands may not be observed when a mixture of fragmented DNA was electrophoresed, due to following reasons

1. Concentration of agarose in the gel was not proper, as greater the concentration of agarose gel used, the greater will be separation of small DNA fragments, whereas smaller the concentration of agarose, higher will be the resolution of bands.
2. If the concentration of salt in the buffer was not proper.
3. If DNA sample is contaminated with RNA or any other impurity or if the concentration of DNA is too low.

Question 10.
Name and describe the technique that helps in separating the DNA fragments by the use of restriction endonuclease.
Or
(i) Name the technique used for the separation of DNA fragments.
(ii) Write the type of matrix used in this technique.
(iii) How is the prepared DNA visualised and extracted for use in recombinant technology?
Answer:
(i) DNA fragments can be separated by the technique called gel electrophoresis.
(ii) The most commonly used matrix is agarose gel, which is a natural polymer extracted from sea weeds.
(iii) A compound called Ethidium Bromide (EtBr) stains DNA, which on exposure with ultraviolet radiationals gives orange light. Hence, DNA fragments appear as orange bands.

Question 11.
A plasmid DNA and a linear DNA (both of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band while, linear DNA shows two fragments. Explain.
Answer:
This is because plasmid is a circular DNA molecule.
When cut with enzyme, it becomes linear, but does not get fragmented. Whereas, a linear DNA molecule gets cut into two fragments. Hence, a single DNA band is observed for plasmid while, two DNA bands are observed for linear DNA in agarose gel.

Question 12.
Write the role of ‘ori’ and ‘restriction site’ in a cloning vector pBR322.
Answer:
Ori is the site where replication starts. This site is responsible for controlling the copy number of a vector. Restriction site is the site of ligation of alien/foreign DNA in the vector, in one of the two antibiotic resistance sites or coding sequence of β- galactosidase.

Question 13.
Write a short note on plasmids.
Answer:
These are small and double-stranded extrachromosomal DNA molecules having an origin of replication. They occur naturally in bacteria. Naturally occurring plasmids are not suitable for the cloning of genes. They are genetically engineered and made suitable for cloning.

Such plasmids are called cloning plasmids. A suitable cloning plasmid should preferably have the following properties

• It should be non-conjugative.
• It should have a relaxed replication and a high copy number.
• It should have an origin of replication.
• It should have unique restriction sites.
• It should have antibiotic marker gene for selection.

The most common cloning plasmid is designated as pBR322, where p stands for the word plasmid and B and R signify the names of its engineers (B. Boliver and R. Rodriguez) 322 is a numerical designation that has a relevance to these workers, who worked out the plasmid.

Question 14.
You have chosen a plasmid as vector for cloning your gene. However, this vector plasmid lacks a selectable marker. How would it affect your experiment?
Answer:
In a gene cloning experiment, first a recombinant DNA molecule is constructed, where the gene of interest is ligated to the vector and introduced inside the host cell (transformation). Since, not all the cells gets transformed with the recombinant/plasmid DNA, in the absence of selectable marker, it will be difficult to distinguish between transformants and non-transformants. Because the role of selectable marker is in the selection of transformants.

Question 15.
Draw a schematic sketch of pBR322 plasmid and label the following in it.
(i) Any two restriction sites
(ii) Ori and rop genes
(iii) An antibiotic resistant gene
Answer:
The labelled diagram of pBR322 plasmid is shown in the figure with
(i) Eco RI and Bam HI as restriction enzymes
(ii) Ori and rop genes
(iii) amp^R (an antibiotic resistant gene)

E. coli cloning vector pBR322

Question 16.
(i) How are recombinant vectors created?
(ii) For creating one recombinant vector only one type of restriction endonuclease is required. Give reason.
Answer:
(i) The vector DNA is cut at a particular restriction site using a restriction enzyme (to cut the desired DNA segment). The alien DNA is then linked with the plasmid DNA using an enzyme called ligase to form the recombinant vector.

(ii) Since, a restriction enzyme recognises and cuts the DNA at a particular sequence is called recognition site, the same restriction enzyme is used for cutting the DNA segment from both the vector and the other source to achieve as ends.

Question 17.
How bacterial cells are made competent to take up DNA?
Or
Describe the role of CaCl₂ in the prepration of competent cell.
Answer:
Since, DNA is a hydrophilic molecule, it cannot pass through the cell membranes. In order to force bacteria to take up the plasmid, the bacterial cells must first be made competent to take up foreign DNA. This is done by treating them with a specific concentration of a divalent cation such as calcium (Ca²⁺), which increases the efficiency with which DNA enters the bacterium through the pores in its cell wall.

Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 42°C (heat shock), and then putting them back on ice. This enables the bacteria to take up the recombinant DNA.

Question 18.
PCR is a useful tool for early diagnosis of an infectious disease. Comment.
Answer:
PCR is a very sensitive technique, which enables the specific amplification of desired DNA from a limited amount of DNA containing sample. Hence, it can detect the presence of an infectious organism in the patient at an early stage of infection (even before the infectious organism has multiplied to large number).

Question 19.
(i) Explain how to find whether an E coli bacterium has transformed or not, when a recombinant DNA bearing ampicillin-resistance gene is transferred into it
(ii) What does the ampicillin-resistant gene act as, in the above case?
Answer:
(i) The recombinant/transformant can be selected out from the non-recombinants/ non-transformants by plating the transformants on ampicillin-containing medium. The transformants will grow in it, while the non-transformants will not grow.
(ii) It acts as a selectable marker.

Question 20.
Name the source of the DNA polymerase used in PCR technique. Mention, why it is used ?
Or
Give the name of the organism from where the thermostable DNA polymerase is isolated. State its role in genetic engineering.
Answer:
Bacterium Thermus aquaticus is a source of enzyme Taq polymerase. As, it is a thermostable enzyme and works at high temperature, it is used to amplify DNA in vitro by PCR. The amplified fragment of desired DNA can be used to ligate with the vector for further cloning.

Question 21.
Rearrange the following in the correct sequence to accomplish an important biotechnological reaction
(a) In vitro synthesis of copies of DNA of interest
(b) Chemically synthesised oligonucleotides
(c) Enzyme DNA polymerase
(d) Complementary region of DNA
(e) Genomic DNA template
(f) Nucleotides provided
(g) Primers
(h) Thermostable DNA-polymers (From Thermus aquaticus)
(i) Denaturation of dsDNA
Answer:

(i) Denaturation of dsDNA
↓
(e) Genomic DNA template
↓
(g) Primers
↓
(b) Chemically synthesised oligonucleotides
↓
(d) Complementary region of DNA
↓
(f) Nucleotides provided
↓
(c) Enzyme DNA polymerase
↓
(h) Thermostable DNA polymerase (from Thermus aquaticus )
↓
(a) In vitro synthesis of copies of DNA of interest

Question 22.
While doing a PCR, denaturation step is missed. What will be its effect on the process?
Answer:
If denaturation of double-stranded DNA does not take place, then primers will not be able to anneal to the template. Amplification will not occur and no extension will take place.

Question 23.
A schematic representation of PCR up to the extension stage is given below. Give answers of the following questions.

(i) Name the process A
(ii) Identify B.
(iii) Identify C and mention its importance in PCR.
Answer:
(i) A – Denaturation process
(ii) B – Primers
(iii) C – Taq DNA polymerase.
Taq polymerase is a thermostable enzyme, which remains active during the high temperature and induces denaturation of DNA.

Differentiate between the following (for complete chapter)

Question 1.
Exonucleases and Endonucleases.
Answer:
Differences between exonucleases and endonucleases are as follows

Exonucleases	Endonucleases
Remove nucleotide from the outer ends of the DNA.	Make cuts at specific positions within the DNA.
It makes cut at only one of the two strands of DNA.	It makes cuts at both strands of DNA simultaneously.
e.g., snake venom and spleen phosphodiesterase.	e.g., deoxyribonuclease 1 and II.

Question 2.
Plasmid and Chromosomal DNA.
Answer:
Differences between plasmid and chromosomal DNA are as follows

Plasmid DNA	Chromosomal DNA
Extrachromosomal circular DNA.	Generally linear.
Not associated with histone proteins.	Associated with histone proteins.
Contains very few genes, but may not be necessary for the cell.	It Consists of complete genome vital for the cellular functions.
Replicates independently.	Replicates with genome.

Question 3.
Electroporation and Microinjection.
Answer:
Differences between electroporation and microinjection are as follows

Electroporation	Microinjection
In this method, electric field is applied to cells in order to increase the permeability of the cell membrane, allowing DNA to be introduced into the cell.	This is a vectorless method of direct delivery of recombinant DNA into plant and animal cells.
In this, brief pulses of high voltage electric currents are passed through the medium.	The foreign DNA is delivered into the nucleus with the help of microinjection or micropipette.
This procedure is mostly used for transforming plant protoplasts.	This method is particularly used for mammalian cells.

Question 4.
Type-I endonuclease and Type II endonuclease.
Answer:
Differences between type-I endonuclease and type-II endonuclease are as follows

Type-I endonuclease	Type-II
They consist of 3 different subunits.	They are structurally simple.
Require ATP, Mg2+, S-adenosyl-methionine for restriction.	Required Mg2+; for restriction.
Recognise specific sequences, but do not cut these sites.	Recognise specific sites and cut them.