Class XII Chapter 8 Human Health and Disease Biology

Transcription

1 Class XII Chapter 8 Human Health and Disease Biology Question 1: What are the various public health measures, which you would suggest as safeguard against infectious diseases? Public health measures are preventive measures which are taken to check the spread of various infectious diseases. These measures should be taken to reduce the contact with infectious agents. Some of these methods are: (1) Maintenance of personal and public hygiene:it is one of the most important methods of preventing infectious diseases. This measure includes maintaining a clean body, consumption of healthy and nutritious food, drinking clean water, etc. Public hygienic includes proper disposal of waste material, excreta, periodic cleaning, and disinfection of water reservoirs. (2) Isolation: To prevent the spread of air-borne diseases such as pneumonia, chicken pox, tuberculosis, etc., it is essential to keep the infected person in isolation to reduce the chances of spreading these diseases. (3) Vaccination: Vaccination is the protection of the body from communicable diseases by administering some agent that mimics the microbe inside the body. It helps in providing passive immunizationto the body. Several vaccines are available against many diseases such as tetanus, polio, measles, mumps, etc. (4) Vector Eradication: Various diseases such as malaria, filariasis, dengue, and chikungunya spread through vectors. Thus, these diseases can be prevented by providing a clean environment and by preventing the breeding of mosquitoes. This can be achieved by not allowing water to stagnate around residential areas. Also, measures like regular cleaning of coolers, use of mosquito nets and insecticides such as malathion in drains, ponds, etc. can be undertaken to ensure a healthy environment. Introducing fish such as Gambusia in ponds also controls the breeding of mosquito larvae in stagnant water. Page 1 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

2 Class XII Chapter 8 Human Health and Disease Biology Question 2: In which way has the study of biology helped us to control infectious diseases? Various advancements that have occurred in the field of biology have helped us gain a better understanding to fight against various infectious diseases. Biology has helped us study the life cycle of various parasites, pathogens, and vectors along with the modes of transmission of various diseases and the measures for controlling them. Vaccination programmes against several infectious diseases such as small pox, chicken pox, tuberculosis, etc. have helped eradicate these diseases. Biotechnology has helped in the preparation of newer and safer drugs and vaccines. Antibiotics have also played an important role in treating infectious diseases. Question 3: How does the transmission of each of the following diseases take place? (a) Amoebiasis (b) Malaria (c) Ascariasis (d) Pneumonia Disease Causative organism Mode of transmission a. Amoebiasis Entamoeba histolytica It is a vector-borne disease that spreads by the means of contaminated food and water. The vector involved in the transmission of this disease is the housefly. b. Malaria Plasmodium sp. It is a vector-borne disease that spreads by the biting of the female Anopheles mosquito. Page 2 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

3 Class XII Chapter 8 Human Health and Disease Biology c. Ascariasis Ascaris lumbricoides It spreads via contaminated food and water. d. Pneumonia Streptococcus pneumoniae It spreads by the sputum of an infected person. Question 4: What measure would you take to prevent water-borne diseases? Water-borne diseases such as cholera, typhoid, hepatitis B, etc. spread by drinking contaminated water. These water-borne diseases can be prevented by ensuring proper disposal of sewage, excreta, periodic cleaning. Also, measures such as disinfecting community water reservoirs, boiling drinking water, etc. should be observed. Question 5: Discuss with your teacher what does a suitable gene means, in the context of DNA vaccines. A suitable gene refers to a specific DNA segment which can be injected into the cells of the host body to produce specific proteins. This protein kills the specific diseasecausing organism in the host body and provides immunity. Question 6: Name the primary and secondary lymphoid organs. (a) Primary lymphoid organs include the bone marrow and the thymus. (b) Secondary lymphoid organs are the spleen, lymph nodes, tonsils, Peyer s patches of small intestine, and appendix. Page 3 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

4 Class XII Chapter 8 Human Health and Disease Biology Question 7: The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form: (a) MALT (b) CMI (c) AIDS (d) NACO (e) HIV (a) MALT- Mucosa-Associated Lymphoid Tissue (b) CMI- Cell-Mediated Immunity (c) AIDS- Acquired Immuno Deficiency Syndrome (d) NACO- National AIDS Control Organization (e) HIV- Human Immuno Deficiency virus Question 8: Differentiate the following and give examples of each: (a) Innate and acquired immunity (b) Active and passive immunity (a) Innate and acquired immunity Innate immunity Acquired immunity 1. It is a non pathogen specific type of defense mechanism. 1. It is a pathogen specific type of defense mechanism. 2. It is inherited from parents and protects the individual since birth. 2. It is acquired after the birth of an individual. Page 4 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

5 Class XII Chapter 8 Human Health and Disease Biology 3. It operates by providing barriers against the entry of foreign infectious agents. 3. It operates by producing primary and secondary responses, which are mediated by B lymphocytes and T- lymphocytes. 4 It does not have a specific memory. 4 It is characterized by an immunological memory. (b) Active and passive immunity Active immunity Passive immunity 1. It is a type of acquired immunity in which the body produces its own antibodies against diseasecausing antigens. 1. It is a type of acquired immunity in which readymade antibodies are transferred from one individual to another. 2. It has a long lasting effect. 2. It does not have long lasting effect. 3. It is slow. It takes time in producing antibodies and giving responses. 3. It is fast. It provides immediate relief. 4. Injecting microbes through vaccination inside the body is an example of active immunity. 4. Transfer of antibodies present in the mother s milk to the infant is an example of passive immunity. Question 9: Draw a well-labelled diagram of an antibody molecule. Page 5 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

6 Class XII Chapter 8 Human Health and Disease Biology Question 10: What are the various routes by which transmission of human immunodeficiency virus takes place? AIDS (Acquired Immuno Deficiency Syndrome) is caused by the Human immunodeficiency virus (HIV). It has the following modes of transmission: (a) Unprotected sexual contact with an infected person. (b) Transfusion of blood from a healthy to an infected person. (c) Sharing infected needles and syringes. (d) From an infected mother to a child through the placenta. Question 11: What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person? Page 6 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

7 Class XII Chapter 8 Human Health and Disease Biology AIDS (Acquired Immuno Deficiency Syndrome) is caused by the Human immunodeficiency virus (HIV) via sexual or blood-blood contact. After entering the human body, the HIV virus attacks and enters the macrophages. Inside the macrophages, the RNA of the virus replicates with the help of enzyme reverse transcriptase and gives rise to viral DNA. Then, this viral DNA incorporates into the host DNA and directs the synthesis of virus particles. At the same time, HIV enters helper T- lymphocytes. It replicates and produces viral progeny there. These newly formed progeny viruses get released into the blood, attacking other healthy helper T- lymphocytes in the body. As a result, the number of T-lymphocytes in the body of an infected person decreases progressively, thereby decreasing the immunity of a person. Question 12: How is a cancerous cell different from a normal cell? Normal cell Cancerous cell 1. Normal cells show the property of contact inhibition. Therefore, when these cells come into contact with other cells, they stop dividing. 1 Cancerous cells lack the property of contact inhibition. Therefore, they continue to divide, thereby forming a mass of cells or tumor. 2. They undergo differentiation after attaining a specific growth. 2. They do not undergo differentiation. 3. These cells remain confined at a particular location. 3 These cells do not remain confined at a particular location. They move into neighboring tissues and disturb its function. Page 7 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

8 Class XII Chapter 8 Human Health and Disease Biology Question 13: Explain what is meant by metastasis. The property of metastasis is exhibited by malignant tumors. It is the pathological process of spreading cancerous cells to the different parts of the body. These cells divide uncontrollably, forming a mass of cells called tumor. From the tumor, some cells get sloughed off and enter into the blood stream. From the blood stream, these cells reach distant parts of the body and therefore, initiate the formation of new tumors by dividing actively. Question 14: List the harmful effects caused by alcohol/drug abuse. Alcohol and drugs have several adverse effects on the individual, his family, and the society. A. Effects of alcohol: Effects on the individual: Alcohol has an adverse effect on the body of an individual. When an individual consumes excess alcohol, it causes damage to the liver and the nervous system. As a result, other symptoms such as depression, fatigue, aggression, loss of weight and appetite may also be observed in the individual. Sometimes, extreme levels of alcohol consumption may also lead to heart failure, resulting coma and death. Also, it is advisable for pregnant women to avoid alcohol as it may inhibit normal growth of the baby. Effects on the family: Consumption of excess alcohol by any family member can have devastating effects on the family. It leads to several domestic problems such as quarrels, frustrations, insecurity, etc. Effects on the society: (a) Rash behavior (b) Malicious mischief and violence (c) Deteriorating social network Page 8 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

9 Class XII Chapter 8 Human Health and Disease Biology (d) Loss of interest in social and other activities B Effects of drugs: An individual who is addicted to drugs creates problems not only for himself but also for his family. Effects on the individual: Drugs have an adverse effect on the central nervous system of an individual. This leads to the malfunctioning of several other organs of the body such as the kidney, liver, etc. The spread of HIV is most common in these individuals as they share common needles while injecting drugs in their body. Drugs have long-term side effects on both males and females. These side effects include increased aggressiveness, mood swings, and depression Effects on the family and society: A person addicted to drugs creates problems for his family and society. A person dependant on drugs becomes frustrated, irritated, and anti-social. Question 15: Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence? Yes, friends can influence one to take drugs and alcohol. A person can take the following steps for protecting himself/herself against drug abuse: (a) Increase your will power to stay away from alcohol and drugs. One should not experiment with alcohol for curiosity and fun. (b) Avoid the company of friends who take drugs. (c) Seek help from parents and peers. (d) Take proper knowledge and counseling about drug abuse. Devote your energy in other extra-curricular activities. (e) Seek immediate professional and medical help from psychologists and psychiatrists if symptoms of depression and frustration become apparent. Page 9 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

10 Class XII Chapter 8 Human Health and Disease Biology Question 16: Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher. Drug and alcohol consumption has an inherent addictive nature associated with euphoria and a temporary feeling of well-being. Repeated intake of drugs increases the tolerance level of the body s receptors, leading to more consumption of drugs. Question 17: In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided? Many factors are responsible for motivating youngsters towards alcohol or drugs. Curiosity, need for adventure and excitement, experimentation are the initial causes of motivation. Some youngsters start consuming drugs and alcohol in order to overcome negative emotions (such as stress, pressure, depression, frustration) and to excel in various fields. Several mediums like television, internet, newspaper, movies etc. are also responsible for promoting the idea of alcohol to the younger generation. Amongst these factors, reasons such as unstable and unsupportive family structures and peer pressure can also lead an individual to be dependant on drugs and alcohol. Preventive measures against addiction of alcohol and drugs: (a) Parents should motivate and try to increase the will power of their child. (b) Parents should educate their children about the ill-effects of alcohol. They should provide them with proper knowledge and counselling regarding the consequences of addiction to alcohol. (c) It is the responsibility of the parent to discourage a child from experimenting with alcohol. Youngsters should be kept away from the company of friends who consume drugs. Page 10 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

11 Class XII Chapter 8 Human Health and Disease Biology (d) Children should be encouraged to devote their energy in other extra- curricular and recreational activities. (e) Proper professional and medical help should be provided to a child if sudden symptoms of depression and frustration are observed. Page 11 of 11 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

12 Class XII Chapter 9 Strategies for Enhancement in Food Production Biology Question 1: Explain in brief the role of animal husbandry in human welfare. Animal husbandry deals with the scientific management of livestock. It includes various aspects such as feeding, breeding, and control diseases to raise the population of animal livestock. Animal husbandry usually includes animals such as cattle, pig, sheep, poultry, and fish which are useful for humans in various ways. These animals are managed for the production of commercially important products such as milk, meat, wool, egg, honey, silk, etc. The increase in human population has increased the demand of these products. Hence, it is necessary to improve the management of livestock scientifically. Question 2: If your family owned a dairy farm, what measures would you undertake to improve the quality and quantity of milk production? Dairy farm management deals with processes which aim at improving the quality and quantity of milk production. Milk production is primarily dependent on choosing improved cattle breeds, provision of proper feed for cattle, maintaining proper shelter facilities, and regular cleaning of cattle. Choosing improved cattle breeds is an important factor of cattle management. Hybrid cattle breeds are produced for improved productivity. Therefore, it is essential that hybrid cattle breeds should have a combination of various desirable genes such as high milk production and high resistance to diseases. Cattle should also be given healthy and nutritious food consisting Page 1 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

13 Class XII Chapter 9 Strategies for Enhancement in Food Production Biology of roughage, fibre concentrates, and high levels of proteins and other nutrients. Cattle s should be housed in proper cattle-houses and should be kept in well ventilated roofs to prevent them from harsh weather conditions such as heat, cold, and rain. Regular baths and proper brushing should be ensured to control diseases. Also, time-to-time check ups by a veterinary doctor for symptoms of various diseases should be undertaken. Question 3: What is meant by the term breed? What are the objectives of animal breeding? A breed is a special variety of animals within a species. It is similar in most characters such as general appearance, size, configuration, and features with other members of the same species. Jersey and Brown Swiss are examples of foreign breeds of cattle. These two varieties of cattle have the ability to produce abundant quantities of milk. This milk is very nutritious with high protein content. Objectives of animal breeding: (i) To increase the yield of animals. (ii) To improve the desirable qualities of the animal produce. (iii) To produce disease-resistant varieties of animals. Question 4: Name the methods employed in animal breeding. According to you which one of the methods is best? Why? Page 2 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

14 Class XII Chapter 9 Strategies for Enhancement in Food Production Biology Animal breeding is the method of mating closely related individuals. There are several methods employed in animals breeding, which can be classified into the following categories: (A) Natural methods of breeding include inbreeding and out-breeding. Breeding between animals of the same breed is known as inbreeding, while breeding between animals of different breeds is known as out-breeding. Outbreeding of animals is of three types: (a). Out-crossing: In this type of out-breeding, the mating of animals occurs within the same breed. Thus, they have no common ancestors up to the last 4-5 generations. (b). Cross-breeding: In this type of out-breeding, the mating occurs between different breeds of the same species, thereby producing a hybrid. (c). Interspecific hybridization: In this type of out-breeding, the mating occurs between different species. (B) Artificial methods of breeding include modern techniques of breeding. It involves controlled breeding experiments, which are of two types:- (a). Artificial insemination: It is a process of introducing the semen (collected from the male) into the oviduct or the uterus of the female body by the breeder. This method of breeding helps the breeder overcome certain problems faced in abnormal mating. (b). Multiple ovulation embryo technology (MOET): It is a technique for cattle improvement in which super-ovulation is induced by a hormone injection. Then, fertilization is achieved by artificial insemination and early embryos are collected. Each of these embryos are then transplanted into the surrogate mother for further development of the embryo. The best method to carry out animal breeding is the artificial method of breeding, which includes artificial insemination and MOET technology. These Page 3 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

15 Class XII Chapter 9 Strategies for Enhancement in Food Production Biology technologies are scientific in nature. They help overcome problems of normal mating and have a high success rate of crossing between mature males and females. Also, it ensures the production of hybrids with the desired qualities. This method is highly economical as a small amount of semen from the male can be used to inseminate several cattle. Question 5: What is apiculture? How is it important in our lives? Apiculture is the practice of bee-keeping for the production of various products such as honey, bee s wax, etc. Honey is a highly nutritious food source and is used as an indigenous system of medicines. It is useful in the treatment of many disorders such as cold, flu, and dysentery. Other commercial products obtained from honey bees include bee s wax and bee pollen. Bee s wax is used for making cosmetics, polishes, and is even used in several medicinal preparations. Therefore, to meet the increasing demand of honey, people have started practicing bee-keeping on a large scale. It has become an income generating activity for farmers since it requires a low investment and is labour intensive. Question 6: Discuss the role of fishery in enhancement of food production. Fishery is an industry which deals with catching, processing, and marketing of fishes and other aquatic animals that have a high economic value. Some commercially important aquatic animals are prawns crabs, oysters, lobsters, and octopus. Fisheries play an important role in the Indian economy. This is Page 4 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

16 Class XII Chapter 9 Strategies for Enhancement in Food Production Biology because a large part of the Indian population is dependent on fishes as a source of food, which is both cheap and high in animal protein. A Fishery is an employment generating industry especially for people staying in the coastal areas. Both fresh water fishes (such as Catla, Rohu, etc) and marine fishes (such as tuna, mackerel pomfret, etc.) are of high economic value. Question 7: Briefly describe various steps involved in plant breeding. Plant breeding is the process in which two genetically dissimilar varieties are purposely crossed to produce a new hybrid variety. As a result, characteristics from both parents can be obtained in the hybrid plant variety. Thus, it involves the production of a new variety with the desired characteristics such as resistance to diseases, climatic adaptability, and better productivity. The various steps involved in plant breeding are as follows: (a). Collection of genetic variability: Genetic variability from various wild relatives of the cultivated species are collected to maintain the genetic diversity of a species. The entire collection of the diverse alleles of a gene in a crop is called the germplasm collection. (b). Evaluation of germplasm and selection of parents: The germplasm collected is then evaluated for the desirable genes. The selected plants with the desired genes are then used as parents in plant breeding experiments and are multiplied by the process of hybridization. (c). Cross-hybridization between selected parents: The next step in plant breeding is to combine the desirable characters present in two different parents to produce hybrids. It is a tedious job as one has to ensure that the Page 5 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

17 Class XII Chapter 9 Strategies for Enhancement in Food Production Biology pollen grains collected from the male parent reach the stigma of the female parent. (d). Selection of superior hybrids: The progenies of the hybrids having the desired characteristics are selected through scientific evaluation. The selected progenies are then self-pollinated for several generations to ensure homozygosity. (e). Testing, release, and commercialization of new cultivars: The selected progenies are evaluated for characters such as yield, resistance to diseases, performance, etc. by growing them in research fields for at least three growing seasons in different parts of the country. After thorough testing and evaluation, the selected varieties are given to the farmers for growing in fields for a large-scale production. Question 8: Explain what is meant by biofortification. Biofortification is a process of breeding crops with higher levels of vitamins, minerals, proteins, and fat content. This method is employed to improve public health. Breeding of crops with improved nutritional quality is undertaken to improve the content of proteins, oil, vitamins, minerals, and micro-nutrients in crops. It is also undertaken to upgrade the quality of oil and proteins. An example of this is a wheat variety known as Atlas 66, which has high protein content in comparison to the existing wheat. In addition, there are several other improved varieties of crop plants such as rice, carrots, spinach etc. which have more nutritious value and more nutrients than the existing varieties. Page 6 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

18 Class XII Chapter 9 Strategies for Enhancement in Food Production Biology Question 9: Which part of the plant is best suited for making virus-free plants and why? Apical and axillary meristems of plants is used for making virus-free plants. In a diseased plant, only this region is not infected by the virus as compared to the rest of the plant region. Hence, the scientists remove axillary and apical meristems of the diseased plant and grow it in vitro to obtain a disease-free and healthy plant. Virus-free plants of banana, sugarcane, and potato have been obtained using this method by scientists. Question 10: What is the major advantage of producing plants by micropropagation? Micropropagation is a method of producing new plants in a short duration using plant tissue culture. Some major advantages of micropropagation are as follows: (a) Micropropagation helps in the propagation of a large number of plants in a short span of time. (b) The plants produced are identical to the mother plant. (c) It leads to the production of healthier plantlets, which exhibit better disease-resisting powers. Question 11: Find out what the various components of the medium used for propagation of explants in vitro are? Page 7 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

19 Class XII Chapter 9 Strategies for Enhancement in Food Production Biology The major components of medium used for propagation of explants in vitro are carbon sources such as sucrose, inorganic salts, vitamins, amino acids, water, agar-agar, and certain growth hormones such as auxins and gibberellins. Question 12: Name any five hybrid varieties of crop plants which have been developed in India. The five hybrid varieties of crop plants which have been developed in India are: Crop plant Hybrid variety Wheat Rice Sonalika and kalian sona Jaya and Ratna Cauliflower Pusa shubra and Pusa snowball K-1 Cowpea Mustard Pusa komal Pusa swarnim Page 8 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

20 Class XII Chapter 10 Microbes in Human Welfare Biology Question 1: Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why? Curd can be used as a sample for the study of microbes. Curd contains numerous lactic acid bacteria (LAB) or Lactobacillus. These bacteria produce acids that coagulate and digest milk proteins. A small drop of curd contains millions of bacteria, which can be easily observed under a microscope. Question 2: Give examples to prove that microbes release gases during metabolism. The examples of bacteria that release gases during metabolism are: (a) Bacteria and fungi carry out the process of fermentation and during this process, they release carbon dioxide. Fermentation is the process of converting a complex organic substance into a simpler substance with the action of bacteria or yeast. Fermentation of sugar produces alcohol with the release of carbon dioxide and very little energy. (b) The dough used for making idli and dosa gives a puffed appearance. This is because of the action of bacteria which releases carbon dioxide. This CO 2 released from the dough gets trapped in the dough, thereby giving it a puffed appearance. Question 3: In which food would you find lactic acid bacteria? Mention some of their useful applications. Page 1 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

21 Class XII Chapter 10 Microbes in Human Welfare Biology Lactic acid bacteria can be found in curd. It is this bacterium that promotes the formation of milk into curd. The bacterium multiplies and increases its number, which converts the milk into curd. They also increase the content of vitamin B 12 in curd. Lactic acid bacteria are also found in our stomach where it keeps a check on the disease-causing micro-organisms. Question 4: Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve use of microbes. (a) Wheat: Product: Bread, cake, etc. 2. Rice: Product: Idli, dosa 2. Bengal gram: Product: Dhokla, Khandvi Question 5: In which way have microbes played a major role in controlling diseases caused by harmful bacteria? Several micro-organisms are used for preparing medicines. Antibiotics are medicines produced by certain micro-organisms to kill other disease-causing micro-organisms. These medicines are commonly obtained from bacteria and fungi. They either kill or stop the growth of disease-causing micro-organisms. Streptomycin, tetracycline, and penicillin are common antibiotics. Penicillium notatum produces chemical penicillin, which checks the growth of staphylococci bacteria in the body. Antibiotics are designed to destroy bacteria by weakening their cell walls. As a result of this weakening, certain immune cells such as the white blood cells enter the bacterial cell Page 2 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

22 Class XII Chapter 10 Microbes in Human Welfare Biology and cause cell lysis. Cell lysis is the process of destroying cells such as blood cells and bacteria. Question 6: Name any two species of fungus, which are used in the production of the antibiotics. Antibiotics are medicines that are produced by certain micro-organisms to kill other disease-causing micro-organisms. These medicines are commonly obtained from bacteria and fungi. The species of fungus used in the production of antibiotics are: Antibiotic Fungus source 1. Penicillin Penicillium notatum 2. Cephalosporin Cephalosporium acremonium Question 7: What is sewage? In which way can sewage be harmful to us? Sewage is the municipal waste matter that is carried away in sewers and drains. It includes both liquid and solid wastes, rich in organic matter and microbes. Many of these microbes are pathogenic and can cause several water- borne diseases. Sewage water is a major cause of polluting drinking water. Hence, it is essential that sewage water is properly collected, treated, and disposed. Question 8: What is the key difference between primary and secondary sewage treatment? Primary sewage treatment Secondary sewage treatment Page 3 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

23 Class XII Chapter 10 Microbes in Human Welfare Biology 1. It is a mechanical process involving the removal of coarse solid materials. 1. It is a biological process involving the action of microbes. 2. It is inexpensive and relatively less complicated. 2. It is a very expensive and complicated process. Question 9: Do you think microbes can also be used as source of energy? If yes, how? Yes, microbes can be used as a source of energy. Bacteria such as Methane bacterium is used for the generation of gobar gas or biogas. The generation of biogas is an anaerobic process in a biogas plant, which consists of a concrete tank (10 15 feet deep) with sufficient outlets and inlets. The dung is mixed with water to form the slurry and thrown into the tank. The digester of the tank is filled with numerous anaerobic methane-producing bacteria, which produce biogas from the slurry. Biogas can be removed through the pipe which is then used as a source of energy, while the spent slurry is removed from the outlet and is used as a fertilizer. Question 10: Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished. Microbes play an important role in organic farming, which is done without the use of chemical fertilizers and pesticides. Bio-fertilizers are living organisms which help increase the fertility of soil. It involves the selection of beneficial micro-organisms that help in improving plant growth through the supply of plant nutrients. Biofertilizers are introduced in seeds, roots, or soil to mobilize the availability of nutrients. Thus, they are extremely beneficial in enriching the soil with organic nutrients. Many species of bacteria and cyanobacteria have the ability to fix free Page 4 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

24 Class XII Chapter 10 Microbes in Human Welfare Biology atmospheric nitrogen. Rhizobium is a symbiotic bacteria found in the root nodules of leguminous plants. Azospirillium and Azotobocter are free living nitrogen-fixing bacteria, whereas Anabena, Nostoc and Oscillitoria are examples of nitrogen-fixing cyanobacteria. Bio-fertilizers are cost effective and eco-friendly. Microbes can also act as bio-pesticides to control insect pests in plants. An example of bio-pesticides is Bacillus thuringiensis, which produces a toxin that kills the insect pests. Dried bacterial spores are mixed in water and sprayed in agricultural fields. When larvae of insects feed on crops, these bacterial spores enter the gut of the larvae and release toxins, thereby it. Similarly, Trichoderma are free living fungi. They live in the roots of higher plants and protect them from various pathogens. Baculoviruses is another bio-pesticide that is used as a biological control agent against insects and other arthropods. Question 11: Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean? Biological oxygen demand (BOD) is the method of determining the amount of oxygen required by micro-organisms to decompose the waste present in the water supply. If the quantity of organic wastes in the water supply is high, then the number of decomposing bacteria present in the water will also be high. As a result, the BOD value will increase. Therefore, it can be concluded that if the water supply is more polluted, then it will have a higher BOD value. Out of the above three samples, sample C is the most polluted since it has the maximum BOD value of 400 mg/l. After untreated sewage Page 5 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

25 Class XII Chapter 10 Microbes in Human Welfare Biology water, secondary effluent discharge from a sewage treatment plant is most polluted. Thus, sample A is secondary effluent discharge from a sewage treatment plant and has the BOD value of 20 mg/l, while sample B is river water and has the BOD value of 8 mg/l. Hence, the correct label for each sample is: Label BOD value Sample A. 20 mg/l Secondary effluent discharge from a sewage treatment plant B. 8 mg/l River water C. 400 mg/l Untreated sewage water Question 12: Find out the name of the microbes from which Cyclosporin A (an immunosuppressive drug) and Statins (blood cholesterol lowering agents) are obtained. Drug Function Microbe 1. Cyclosporine A Immuno suppressive drug Trichoderma polysporum 2. Statin Blood cholesterol lowering agent Monascus purpureus Question 13: Find out the role of microbes in the following and discuss it with your teacher. (a) Single cell protein (SCP) (b) Soil (a) Single cell protein (SCP) Page 6 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

26 Class XII Chapter 10 Microbes in Human Welfare Biology A single cell protein is a protein obtained from certain microbes, which forms an alternate source of proteins in animal feeds. The microbes involved in the preparation of single cell proteins are algae, yeast, or bacteria. These microbes are grown on an industrial scale to obtain the desired protein. For example, Spirulina can be grown on waste materials obtained from molasses, sewage, and animal manures. It serves as a rich supplement of dietary nutrients such as proteins, carbohydrate, fats, minerals, and vitamins. Similarly, micro-organisms such as Methylophilus and methylotrophus have a large rate of biomass production. Their growth can produce a large amount of proteins. (b) Soil Microbes play an important role in maintaining soil fertility. They help in the formation of nutrient-rich humus by the process of decomposition. Many species of bacteria and cyanobacteria have the ability to fix atmospheric nitrogen into usable form. Rhizobium is a symbiotic bacteria found in the root nodules of leguminous plants. Azospirillium and Azotobocter are free living nitrogen-fixing bacteria, whereas Anabena, Nostoc, and Oscillitoria are examples of nitrogen-fixing cyanobacteria. Question 14: Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas, Citric acid, Penicillin and Curd The order of arrangement of products according to their decreasing importance is: Penicillin- Biogas Citric acid Curd Penicillin is the most important product for the welfare of human society. It is an antibiotic, which is used for controlling various bacterial diseases. The second most important product is biogas. It is an eco-friendly source of energy. The next important product is citric acid, which is used as a food preservative. The least important product is curd, a food item obtained by the action of lactobacillus bacteria on milk Page 7 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

27 Class XII Chapter 10 Microbes in Human Welfare Biology Hence, the products in the decreasing order of their importance are as follows: Penicillin- Biogas Citric acid Curd Question 15: How do biofertilisers enrich the fertility of the soil? Bio-fertilizers are living organisms which help in increasing the fertility of soil. It involves the selection of beneficial micro-organisms that help in improving plant growth through the supply of plant nutrients. These are introduced to seeds, roots, or soil to mobilize the availability of nutrients by their biological activity. Thus, they are extremely beneficial in enriching the soil with organic nutrients. Many species of bacteria and cyanobacteria have the ability to fix free atmospheric nitrogen. Rhizobium is a symbiotic bacteria found in the root nodules of leguminous plants. Azospirillium and Azotobocter are free living nitrogen-fixing bacteria, whereas Anabena, Nostoc, and Oscillitoria are examples of nitrogen-fixing cyanobacteria. Biofertilizers are cost effective and eco-friendly. Page 8 of 8 Website: contact@vidhyarjan.com Mobile: Head Office: 1/3-H-A-2, Street # 6, East Azad Nagar, Delhi (One Km from Welcome Metro Station)

28 CHAPTER 8 HUMAN HEALTH AND DISEASE POINTS TO REMEMBER Carcinogens : Cancer causing agents. e.g., gamma rays. UV rays, dyes and lead. Immuno Suppressant : The chemical which supress the immunity response to antigen partially or completely. Interferon : The glycoproteins produced by our body cells in response to a viral infection. Incubation Period : The time period between infection and the appearance of symptoms. Metastasis : The property in which the cancer cells spread to different sites through blood and develop secondary tumors. Oncogenes : Viral genome which causes cancer. Retrovirus : A virus having RNA as genetic material and forms DNA by reverse transcription and then replicate e.g., Human Immunodeficiency Virus (HIV). Sporozoites : The infective stage of protozoa Plasmodium which is injected into human blood through saliva of female Anopheles mosquito. Syndrome : Collection of disease symptoms responsible for a disorder or a disease. Vaccination : Inoculation of a vaccine to stimulate production of antibodies and provide immunity for one or more disease. PMNL : CMI : ABBREVIATIONS Polymorpho-Nuclear Leukocytes Cell Mediated Immunit 73 XII - BIOLOGY

29 ELISA : Enzyme Linked Immunosorbent Assay HLA : MALT : SCID : Human Leukocyte Antigen Mucosal Associated Lymphoid Tissue Severe Combined Immuno Deficiency NACO : National AIDS Control Organisation MRI : Magnetic Resonance Imaging - Health - The state of complete physical, mental and social well beings - Good health can be achieved by (i) (ii) (iii) (iv) (v) awareness about disease and their effects on different body functions. vaccination control of vectors proper disposal of wastes Maintenance of hygienic food and water resources. - Infectious Diseases (i) Viral Diseases eg. polio, common cold, measles, rabies (ii) Bacterial diseases. eg. Typhoid, pneumonia, Diptheria, Tetanus, (iii) Fungal diseases - eg. Ring worm & Scabies (v) Helminthic diseases-eg Ascariasis, Filariasis, Taeniasis Disease Causative Agents Symptoms 1. Common cold Rhinoviruses Nasal congestion and discharge, sore throat cough, headache, tiredness and hoarseness. 2. Typhoid Salmonella typhi sustained high fever, stomach pain, loss of appetite, constipation, headache. 3. Pneumonia Streptococcus fever, headache, cough, pneumoniae and chills. in severe cases finger Haemophilus nails may turn grey to bluish influenzae in colour. 4. Malaria Plasmodium yaming, tiredness, acute P. malaria, headache, muscular pain, 74 XII - BIOLOGY

30 P.vivax, feeling of chillness and P. falciparum shivering, nausea and high temperatures 5. Amoebic dysentry Entamoeba Abdominal pain, cramps, histolytica stool with excess mucus and blood clots,constipation 6. Ringworm Microsporum Dry scaly lesions on skin, Epidermophyton nails and scalp, itching and Trichophyton 7. Ascariasis Ascaris Anaemia, muscular pain, lumbricoides internal bleeding, insomnia, blockage of intestinal passage 8. Filariasis or Wuchereria fever, blockage of lymphatic Elephantiasis bancrofti and vessels, enormous swelling W. malayi of affected part viz. arm, foot, leg, mamma or scrotum Immunity : Resistance to infections or antigens. Two types of immunities. (i) Innate immunity : inherited by the organism from the parents and protects from birth through out life. Four types of barriers (a) Physical - eg skin, mucus coating epithelium of respiratory, gastrointestinal and urinogenital tracts. (b) Physiological - eg. acid of stomach, lysozymes of saliva and tears (c) Cellular eg. PMNL, monocytes, Neutrophils and macrophages (d) Cytokine - eg virus infected cells secrete proteins called interferons which protect non-infected cells from further infection (ii) Acquired Immunity. Acquired by a person after birth by vaccination or contacting the disease. (a) (b) (c) FACTORS AFFECTING HEALTH Genetic : Child may inherit certain disorders from parents. Life Style : Water/food intake, rest, exercise, personal hygiene. Infection and Corresponding immunity. 75 XII - BIOLOGY

31 Acquired Specific Immunity (Defense Mechanism) Antibody Mediated Immune System Cell Mediated Immune System Antibodies circulating in blood B-Cells T-cells protect and lymph defend against virus against pathogens that and bacteria that enter blood. invade the host tissue. It is based on the principle of memory and immunity. The antigenic preparations of proteins of pathogens or a solution of inactivated or weakened pathogens are introduced in the body. The antigenic properties are recognised. Cascade of reactions forms antibodies. History of reactions is stored as memory. Subsequent exposures result in intensified response. Allergens attach Inflammatory response (allergy B-cells Produce Histamine & Serotonin Plasma cells on second exposure Produce Mast cells Antibodies (Ig E) attach with allergen ( and antibody ) Drugs Criteria Opiods Cannabinoids Coca alkaloids Source Papaver sominiferum Cannabis sativa Erythroxylum (Popply Plant) (Hemp Plant) coca (Coca plant) Part of Plant Fruits (Unripen Inflorescence, Leaves and Capsules) resin leaves, Young twigs Product Opium, Morphine Charas, Ganja Cocaine (Coke/ Heroin/Smack Hashish Marijuana Crack) Mode of Intake Snorting, Injection Oral, Inhalation Snorting Effects Neuro depressant, Interact with Sense of (Property) cannabinoid euphoria Slow down the receptors, interferes with functions Cardiovascular neurof the body system effects otransmitters, Hallucination 76 XII - BIOLOGY

32 Acquired Immunity (i) May be Humoral (containing antibodies which circulate in body fluids). mediated by B.lymphocytes. (ii) Cell-Mediated (CMI) - mediated by T-lymphocytes Acquired immunity may be active or passive. Vaccination and immunisation are based on the property called 'memory' of the immune systems. Symptoms of Allergy Sneezing, watery eyes, rashes, running nose and difficulty in breathing. Auto Immunity - When the immune system of body starts distroying 'self' cells and molecules, called auto immune diseases eg Rheumatoid arthritis, multiple sclerosis and insulin-dependent diabetes. Immune system in the body play an important role in organ transplantation, allergic reactions and auto immune diseases Immune system consists of lymphoid organs, bone marrow, thymus, spleen,lymph nodes and MALT (Mucosal Associated Lymphoid Tissue) AIDS - (Acquired Immuno Dificiency Syndrome) caused by HIV (Human Immunodeficiency Virus) which belongs to retrovirus category of viruses. Modes of transmission By sexual contact with infected person By transfusion of contaminated blood and blood products By sharing the infacted needles From infected mother to child through placenta Persons who are at high risk of getting infection include- Individuals who have multiple sex partners. Drug addicts taking drugs intravenously- Individuals who require repeated blood transfusions - Children born to HIV infected mother Prevention of AIDS - Using disposal syringes and needles, checking the blood of HIV, controlling drug abuse, free distribution of condoms and advocating safe sex. - Main test for AIDS in ELISA (Enzyme Linked Immuno Sorbant Assay) 77 XII - BIOLOGY

33 Cancer - Carcinogens induce the transformation of normal cells into cancerous cells eg. UV rays, X-rays, g-rays, anilene dyes and tumour viruses, cadmium oxide, mustard gas, Ni & Cr compounds etc Two types of tumors. (a) Benign - confined to the area of formation and do not spread to other parts. (b) Malignant - show metastasis ie. cells of these tumors can be carried by blood stream or lymph to other parts of body and form secondaries in neighbouring organs. Treatment - through surgery, radiotherapy, chemotherapy, immunotherapy. QUESTIONS VSA (1 MARK) 1. Name the diagnostic test which confirms typhoid. 2. Name the two major groups of cells required to attain specific immunity. 3. You have heard of many incidences of Chickengunya in our country. Name the vector of the disease. 4. Breast fed babies are more immune to diseases than the bottle fed babies. Why? 5. Name the pathogen which causes malignant malaria. 6. Which microorganism is used to produce hepatitis B Vaccine? 7. What is the reason of shivering in malarial patient? SA-II (2 MARKS) 8. Where are B-cells and T-cells formed? How do they differ from each other? 9. Given below are the pathogens and the diseases caused by them. Which out of these pairs is not correct matching pair and why? (a) Wuchereria - Filariasis (b) Microsporum - Ringworm (c) Salmonella - Common Cold (d) Plasmodium - Malaria 10. What would happen to the immune system, if thymus gland is removed from the body of a person? 11. Lymph nodes are secondary lymphoid organs. Describe the role of lymph nodes in our immune response. 12. What is the role of histamine in inflammatory response? Name few drugs which reduce the symptoms of allergy. 78 XII - BIOLOGY

34 SA-I (3 MARKS) 13. What are Cannabinoids? From which plant Cannabinoids are obtained? Which part of the body is affected by consuming these substances? 14. In the figure, structure of an antibody molecule is shown. Observe it and Give the answer of the following questions. (i) Label the parts A, B and C. (ii) Which cells produce these chemicals? (iii) State the function of these molecules. 15. Mention any three causes of drug abuse. Suggest some measures for the prevention and control of drug abuse. 16. A person shows unwelcome immunogenic reactions while exposed to certain substances. (a) Name this condition. (b) What common term is given to the substances responsible for this condition? (c) Name the cells and the chemical substances released which cause such reactions. 79 XII - BIOLOGY