Answer

(c) Health does not, simply mean ‘absence of disease’ or ‘physical fitness’. It could be defined as a state of complete physical, mental and social well being. When people are healthy, they are happy with smiling face and more efficient at work.

This increases productivity and brings economic prosperity. It also increases longevity of people and reduces infant and maternal mortality.

• (a) Health is the state of body and mind in a balanced condition: This definition is incomplete as it does not encompass the social well-being aspect, which is a crucial component of overall health.

• (b) Health is the reflection of a smiling face: This definition is superficial and misleading. A smiling face does not necessarily indicate good health, as it overlooks the physical, mental, and social dimensions of well-being.

• (d) Health is the symbol of economic prosperity: This definition confuses the outcome of good health with the definition of health itself. While economic prosperity can be a result of good health, it is not a defining characteristic of health.

Answer

(a) A wide range of organisms including bacteria, viruses, fungi, protozoans, helminths, etc., cause diseases in plants and animals. Such disease causing organisms are called pathogens. While vectors are the carriers of pathogens which may be insects or worms.

• (b) Vectors are not the organisms that cause diseases themselves; rather, they are carriers that transmit pathogens from one host to another. Examples include mosquitoes transmitting malaria or ticks transmitting Lyme disease.

• (c) Insects are a broad category of arthropods and not all insects cause diseases. Some insects can act as vectors, but they are not the pathogens themselves.

• (d) Worms, specifically helminths, can cause diseases, but the term “worms” is too specific and does not encompass the full range of disease-causing organisms like bacteria, viruses, and fungi.

Thinking Process

Typhoid fever is caused by pathogenic bacterium Salmonella typhi.

Answer

(d) Typhoid fever could be confirmed by Widal test, while

ELISA (Enzyme Linked Immunosorbent Eassy) is a widely used as diagnostic test for AIDS, PCR test is used to identify the genome sequences of organisms.

ESR (Erythrocyte Sedimentation Rate) test is a type of blood test.

• ELISA test: This test is widely used as a diagnostic test for AIDS, not for typhoid.
• ESR test: This is a type of blood test that measures the rate at which red blood cells sediment in a period of one hour, and it is not specific for diagnosing typhoid.
• PCR test: This test is used to identify the genome sequences of organisms, and it is not specifically used for diagnosing typhoid.

Answer

(d) Influenza, commonly known as the ‘flu’ is an infectious disease of birds and mammals caused by influenza viruses. The most common symptoms are chill, fever, runny nose, sore throat, muscle pain, headache, coughing, weakness/fatigue and discomfort.

Cancer is defined as an uncontrolled division or proliferation of cells without any differentiation. It is a non-infectious disease caused by the agents called carcinogens.

Smallpox is a serious, highly contagious and often life threatening disease characterised by a rash and (blisters) on the face, arms and legs. It is caused by the Variola virus. It get transmitted from a person to other by various means like sneeze, saliva, contaminated body fluids, etc.

Allergy is the exaggerated response of the immune system to certain antigens in the environment (pollen, dust, mites, molds, cloth fibres, animal hair, etc). It occurs due to the release of chemicals like histamine and serotonin from the mast cells. It is non-infectious responsc.

• Option (a) I and II: This option is incorrect because Cancer (I) is a non-infectious disease. It is caused by uncontrolled cell division and proliferation, often due to carcinogens, and does not spread from person to person.

• Option (b) II and III: This option is incorrect because Allergy (III) is a non-infectious disease. It is an exaggerated immune response to environmental antigens like pollen, dust, and animal hair, and does not spread from person to person.

• Option (c) III and IV: This option is incorrect because Allergy (III) is a non-infectious disease. It is an exaggerated immune response to environmental antigens and does not spread from person to person.

Thinking Process

Malaria is caused by a protozoan, Plasmodium. The vector of Plasmodium is female Anopheles mosquito which transfers the sporozoites (infectious form) to the human body by biting.

Answer

(c) Sporozoites enter the female Anopheles mosquito when they bite an infected person where these sporozoite fertilise and multiply in the stomach wall of the female Anopheles and stored in the salivary gland of mosquito till it is again transferred to the human body by a mosquito bite.

After entering the human body the sporozoites reach the liver cells, where they multiply. This is followed by their attack on red blood cells resulting in their rupture. The ruptured RBCs release a toxin called haemozoin, which is responsible for high recurring fever, chills and shivering.

• (a) Liver of human: The liver of a human is where the sporozoites multiply after entering the human body, not where they are formed. The sporozoites are formed in the mosquito’s salivary glands.

• (b) RBCs of mosquito: Red blood cells (RBCs) are not present in mosquitoes. Sporozoites are not formed in the RBCs of mosquitoes; they are formed in the mosquito’s salivary glands.

• (d) Intestine of human: The intestine of a human is not involved in the formation of sporozoites. Sporozoites are formed in the mosquito’s salivary glands and then transferred to the human body through a mosquito bite.

Thinking Process

Disease like dengue and chikungunya are transmitted through insect vectors.

Answer

(b) Chikungunya is transmitted by the vector Aedes mosquitoes. Whereas housefly is the vector for cholera cockroach transmit jaundice or yellow fever and is a carrier of food and waterborne disease female Anopheles is responsible for spreading malaria.

• House flies are vectors for cholera, not chikungunya.
• Cockroaches transmit jaundice or yellow fever and are carriers of food and waterborne diseases, not chikungunya.
• Female Anopheles mosquitoes are responsible for spreading malaria, not chikungunya.

Thinking Process

Pneumonia is caused by the pathogenic bacterium Streptococcus pneumoniae and Haemophilus influenza and spreads inhaling droplet/aerosol from infectid person during sneezing or coughing.

Answer

(a)

• Option (b) is incorrect because the symptoms listed (constipation, abdominal pain, cramps, and blood clots) are indicative of amoebiasis, not pneumonia.

• Option (c) is incorrect because the symptoms listed (nasal congestion and discharge, cough, sore throat, and headache) are indicative of the common cold or influenza, not pneumonia.

• Option (d) is incorrect because the symptoms listed (high fever, weakness, stomach pain, loss of appetite, and constipation) are indicative of typhoid, not pneumonia.

Answer

(c) Normal cells have genes called cellular oncogens or proto-oncogenes which are present in inactivated state, but under certain conditions (like mutation) these get transformed to cancer causing oncogens, whereas structural gene, expressor gene and regulatory genes are responsible for regulation of gene expression (operon model).

• Structural genes are responsible for coding the proteins that are necessary for the structure and function of cells, not for causing cancer.
• Expressor genes are involved in the regulation of gene expression, determining when and where specific genes are turned on or off, but they do not directly cause cancer.
• Regulatory genes control the expression of other genes, including the timing, location, and level of gene expression, but they are not directly responsible for causing cancer.

Answer

(b) Cancer is defined as an uncontrolled division or proliferation of cells without any differentiation. Repeated division of cells form a large mass of tissue called tumours. Tumours are of two types i.e., benign (non-cancerous) and malignant (cancerous).

The invasion of cancerous cells (in malignant tumours) from one part to the other parts of body is called metastasis, while metagenesis is the alteration of generation.

Tetragenesis is a prenatal toxicity characterised by structural, functional defects in the developing embryo or fetus. Mitosis is a type of cell division that results in two daughter cells.

• (a) Metagenesis: Metagenesis is the alteration of generations, typically referring to the life cycle of certain organisms where there is an alternation between sexual and asexual forms. It is not related to the spread of cancerous cells.

• (c) Teratogenesis: Teratogenesis refers to the process by which congenital malformations (birth defects) are produced in an embryo or fetus. It is related to prenatal toxicity and structural or functional defects in the developing embryo or fetus, not the spread of cancerous cells.

• (d) Mitosis: Mitosis is a type of cell division that results in two daughter cells, each having the same number and kind of chromosomes as the parent nucleus. It is a normal process of cell division and growth, not related to the spread of cancerous cells.

Answer

(c) Health can be defined as a state of complete physical, mental and social well being. So, when an apparently healthy person is diagnosed as unhealthy by a psychiatrist, the reason could be that the patient shows behavioural and social maladjustment. Due to mental discomfort.

It patient is not efficient at his/her work and donot show interest in routine, social and sports activities it means that he is physically not well and need treatment by a psychiatrist

• (a) The patient was not efficient at his work: This reason is incorrect because inefficiency at work alone does not necessarily indicate a mental health issue. It could be due to various other factors such as lack of skills, training, or motivation, which are not directly related to mental health.

• (b) The patient was not economically prosperous: Economic prosperity is not a direct indicator of mental health. A person can be mentally healthy regardless of their economic status. Mental health is more closely related to emotional and social well-being rather than financial status.

• (d) He does not take interest in sports: Lack of interest in sports alone is not a sufficient reason to diagnose someone as mentally unhealthy. People have different interests and hobbies, and not everyone is inclined towards sports. Mental health assessments consider a broader range of behavioral and social factors.

Thinking Process

Rheumatoid arthritis which affects many people in our society is an auto-immune disease.

Answer

(b) Autoimmunity is an abnormal immune response in which the immune system of the body starts rejecting its own body cells or ‘self’ cells and molecules. Sometimes, body loose its ability to differentiate between pathogen or foreign molecules from self cell and attacks self-cells. This results in damage to the body.

While if any foreign antigen enters into body the lymphocytes because more active and produces more antibodies in its response in the body.

• Option (a) I and II:

  • Reason: While lymphocytes becoming more active (I) is a part of the immune response, it is not specific to rheumatoid arthritis. The key aspect of rheumatoid arthritis is the body’s immune system attacking its own cells (II), but this option does not include the loss of ability to differentiate between self and foreign cells (IV), which is crucial for the condition.

• Option (c) III and IV:

  • Reason: Although the loss of ability to differentiate between self and foreign cells (IV) is correct, the production of more antibodies (III) is not specific to rheumatoid arthritis. Increased antibody production can occur in many immune responses and is not a defining characteristic of rheumatoid arthritis.

• Option (d) I and III:

  • Reason: Lymphocytes becoming more active (I) and the production of more antibodies (III) are general immune responses and do not specifically address the autoimmune nature of rheumatoid arthritis, where the body attacks its own cells (II) and loses the ability to differentiate between self and foreign cells (IV).

Answer

(c) Transmission of HIV-infection generally occurs by

(i) Sexual contact with infected person

(ii) Transfusion of contaminated blood and blood products.

(iii) Sharing infected needles as in the case of intravenous drug abusers

(iv) Infected mother to her child through placenta.

Shaking hands with infected persons is not a mode of transmission of HIV.

• Transfusion of contaminated blood: HIV can be transmitted through the transfusion of blood that is contaminated with the virus.
• Sharing the infected needles: HIV can be transmitted by sharing needles that have been used by an infected person, as the virus can be present in the blood residue.
• Sexual contact with infected persons: HIV can be transmitted through sexual contact with an infected person, as the virus can be present in bodily fluids such as semen, vaginal fluids, and blood.

Answer

(a) Heroin, commonly called smack, is chemically diacetyl morphine which is a white, odourless, bitter, crystalline compound. This is obtained by acetylation of morphine, extracted from the latex of poppy plant (Papaver somniferum), but Leaves of cannabis sativa commonly called bhang produces cannabinoids.

Flower of Dhatura Active chemical of Dhatura flower is tropane alkaloids mainly scopolamines, hyoscyamine and atroplne.

Fruits of Erythroxyl coca Cocaine is extracted from the dried leaves and young twigs of Erythroxyl coca.

• Leaves of Cannabis sativa: Leaves of cannabis sativa, commonly called bhang, produce cannabinoids, not heroin (smack).

• Flowers of Dhatura pinata: The active chemicals in Dhatura flowers are tropane alkaloids, mainly scopolamine, hyoscyamine, and atropine, not heroin (smack).

• Fruits of Erythroxyl coca: Cocaine is extracted from the dried leaves and young twigs of Erythroxyl coca, not heroin (smack).

Thinking Process

Innate immunity is non-specific type of defense, mechanism of the body which is present at the time of birth. This is accomplished by providing different types of barriers to the entry of the foreign agents into our body.

Answer

(c) The cytokine-barriers include interferons. These are the proteins secreted by virus infected cells, which protect non-infected cells from further viral infection.

Serotonin It is a neurotransmitter that leads to depression.

Colostrum It is present in the lactating mother’s breast milk, contains antibodies which protect the newborn against disease.

Histamine Histamine is also a neurotransmitter involved in inflammatory response.

• Serotonin: It is a neurotransmitter that leads to depression.
• Colostrum: It is present in the lactating mother’s breast milk, contains antibodies which protect the newborn against disease.
• Histamine: Histamine is also a neurotransmitter involved in inflammatory response.

Answer

(d) Transplantation is the replacement of a diseased organ or tissue of an individual with healthy organ or tissue of same or another individual. These transplants or graft gets rejected if it is recognised as foreign antigen by the body’s immune systems.

Cell mediated immune response, mediated by T-lymphocyte in able to differentiate between self and non-self cells/organ. This type of immune response recognise the body’s non-cells or other tissue or organs from other individual as foreign antigen and cause rejection of the graft.

• (a) Auto-immune response: Auto-immune response occurs when the body’s immune system mistakenly attacks its own tissues, thinking they are foreign. This is different from transplant rejection, where the immune system correctly identifies the transplanted tissue as foreign and attacks it.

• (b) Humoral immune response: Humoral immune response involves B-lymphocytes and the production of antibodies to neutralize pathogens. While antibodies can play a role in transplant rejection, the primary mechanism of rejection is through cell-mediated immune response involving T-lymphocytes.

• (c) Physiological immune response: Physiological immune response is a broad term that refers to the normal functioning of the immune system in protecting the body against pathogens. It does not specifically address the mechanisms involved in transplant rejection, which are more accurately described by cell-mediated immune response.

Answer

(b) The yellowish fluidcolostrum is secreted by mother during the initial days of lactation has abundant antibodies ( $\operatorname{Ig} A)$ to protect the infant from several diseases.

IgG immunoglobulin (antibody) is most abundant (appro . $80 \%$ ) antibody in human and found in serum IgA is second abundant (approx . $10-15 \%$ ) antibody. It is found in saliva and tear also. $\lg \mathrm{D}$ and $\lg E$ constitute $2-3 \%$ of total antibodies which are found in most cells and serum.

• IgG type: Although IgG is the most abundant antibody in human serum, it is not the primary antibody found in colostrum. IgG is mainly involved in long-term immunity and is transferred from mother to fetus through the placenta, not through colostrum.

• IgD type: IgD is present in very low concentrations in the serum and is primarily found on the surface of immature B-lymphocytes. It plays a role in the initiation and regulation of immune responses but is not a significant component of colostrum.

• IgE type: IgE is also present in very low concentrations in the serum and is mainly associated with allergic reactions and responses to parasitic infections. It is not a significant component of colostrum and does not play a major role in protecting newborns from diseases through colostrum.

Answer

(a) Tobacco has nicotine, which stimulates the adrenal gland to release adrenaline and noradrenaline which in turn increases the blood pressure and heart rate, while tannic acid is a type of polyphenol used as a mordant, curaimin, obtained from cureumin in a pain releiver and catechine derived from catechu is an antioxidant.

• Tannic acid is a type of polyphenol used as a mordant, not known to stimulate the secretion of adrenaline and noradrenaline.
• Curaimin, obtained from curcumin, is a pain reliever and does not stimulate the secretion of adrenaline and noradrenaline.
• Catechine, derived from catechu, is an antioxidant and does not stimulate the secretion of adrenaline and noradrenaline.

Answer

(c) Snake antivenom is a biological product that typically consists of venom neutralising antibodies derived from a host animal, such as a horse or sheep, it is not considered as antigen or antigen-antibody complex or enzyme.

• (a) Antigens: Antigens are substances that induce an immune response in the body, particularly the production of antibodies. Anti venom does not contain antigens; instead, it contains antibodies that neutralize the venom.

• (b) Antigen-antibody complexes: These are formed when antibodies bind to antigens. Anti venom is not composed of these complexes; it consists of free antibodies that are ready to bind to and neutralize the venom.

• (d) Enzymes: Enzymes are biological molecules that catalyze chemical reactions. Anti venom does not contain enzymes; it contains antibodies specifically designed to neutralize the toxic components of snake venom.

Answer

(c) Lymphoid organs are the organs where origin and/or maturation and proliferation of lymphocytes occur.

The secondary lymphoid organs provide the sites for interaction of lymphocytes with the antigen, which then proliferate to becomes effector cells.

Appendix is sometime not considered as the lymphoid organ, as it has been proposed to be a vestigial structure connected to the cecum, located near the junction of the small intestine and the large intestine.

• Spleen: The spleen is a lymphoid organ that filters blood, removes old and damaged red blood cells, and helps in the immune response by producing lymphocytes.

• Tonsils: Tonsils are lymphoid tissues located at the back of the throat. They play a role in protecting the body from respiratory and gastrointestinal infections by trapping pathogens that enter through the mouth or nose.

• Thymus: The thymus is a primary lymphoid organ where T lymphocytes (T cells) mature. It is crucial for the development of the adaptive immune system.

Answer

(c) The thymus is a lobed organ located near the heart and beneath the breastbone. The thymus is quite large at the time of birth but keeps reducing in size with age and by the time puberty is attained it reduces to a very small size.

While the size of pineal gland (located at brain), pituitary gland (in brain), thyroid (located infront of neck) remains constant in size since birth.

• The pineal gland, located in the brain, does not significantly change in size from birth through adulthood.
• The pituitary gland, also located in the brain, maintains a relatively constant size throughout a person’s life.
• The thyroid gland, located in front of the neck, does not undergo significant size reduction with age; its size remains relatively stable.

Answer

(c) Haemozoin is a toxin released by Plasmodium species, which is responsible for the chill and high fever recurring every three to four days.

To continue their life-cycle, Plasmodium enters the human body as sporozoites and multiply within the liver cells, resulting in the rupture of the RBCs.

The rupture RBCs is associated with release of a toxic substance, haemozoin, while Streptococcus produces streptomycin and streptococcal pyrogenic exotoxin which shows haemolytic and Haemophilus produces cytolethal distending toxin (HdCDT) which inhibit mammals cell proliferation.

• (a) Haemozoin is not a precursor of haemoglobin. Haemoglobin is a protein in red blood cells responsible for carrying oxygen, and its precursors are different molecules involved in the synthesis of haemoglobin, such as protoporphyrin IX and iron.

• (b) Haemozoin is not a toxin from Streptococcus. Streptococcus bacteria produce different toxins, such as streptolysin and streptococcal pyrogenic exotoxin, which are responsible for various infections and symptoms.

• (d) Haemozoin is not a toxin from Haemophilus species. Haemophilus bacteria produce other toxins, such as cytolethal distending toxin (HdCDT), which inhibit mammalian cell proliferation.

Answer

(d) Ringworm infections are caused by fungi belonging to the genera Microsporum, trichophyton and Epidermophyton.

Macrosporum is an ectomycorrhizal zoosporic fungus causing diseases of economically important vascular plants.

• Microsporum: This is incorrect because Microsporum is indeed a causal organism for ringworm.
• Trichophyton: This is incorrect because Trichophyton is indeed a causal organism for ringworm.
• Epidermophyton: This is incorrect because Epidermophyton is indeed a causal organism for ringworm.

Thinking Process

Sickle-cell anaemia is an autosome-linked recessive trait that can be transmitted from heterozygous carrier parents to the offspring.

Answer

(c) Sickle-cell anaemia is related to malaria not to typhoid and person suffering from sickle-cell anaemia are resistant to malarial parasite ar RBC of sickle-cell anaemic patients is distored in shape that not affected by Plasmodium $\mathrm{sp}$.

It is known that heterozygotes $\left(\mathrm{Hb}^{\mathrm{S}} / \mathrm{HB}^{\mathrm{A}}\right)$, having both types of haemoglobin show resistance to malarial infection because the body targets the $P$. falciparum infected cells for destruction.

In contrast, individuals homozygous for normal haemoglobin $\left(\mathrm{Hb}^{\mathrm{A}} / \mathrm{Hb}^{\mathrm{A}}\right)$ suffer high mortality rates in early childhood due to malarial infection.

• (a) more prone to malaria: This is incorrect because individuals with sickle-cell anaemia are actually less prone to malaria. The distorted shape of their red blood cells makes it difficult for the malaria parasite, Plasmodium, to infect and survive in these cells.

• (b) more prone to typhoid: This is incorrect because sickle-cell anaemia is not related to an increased susceptibility to typhoid. Typhoid is caused by a bacterial infection (Salmonella typhi), and there is no evidence to suggest that sickle-cell anaemia affects the likelihood of contracting typhoid.

• (d) less prone to typhoid: This is incorrect because sickle-cell anaemia does not provide any known resistance to typhoid. The condition specifically affects the red blood cells and their interaction with the malaria parasite, not with the bacteria that cause typhoid.

Answer

Certain pathogens are tissue/organ specific as they are adapted to overcome the resistance mechanisms of those tissues and organs, e.g., the pathogens that enter the gut must know a way of surviving in the stomach at low $\mathrm{pH}$ and resistant to various digestive enzymes.

Answer

The immune system of a person is suppressed. In the ELISA test, he was found positive to a pathogen.

(a) The patient is suffering from AIDS.

(b) AIDS is caused by Human Immuno deficiency Virus (HIV). It is a retro virus containing RNA as genetic material.

(c) Macrophages and helper T-cells are affected by the pathogen.

Thinking Process

Lymphocytes are of two types i.e., T-lymphocytes or T-cells and B-lymphocytes or B-cells.

Answer

Both type of lymphocytes and other cells of the immune system are produced in the bone marrow.

$B$ and $T$-cells are different from each other in the following aspects

Answer

(c) Wuchereria species bancrofti and W malayi), the filarial worms cause a slowly developing chronic inflammation of the organs in which they live for many years, usually the lymphatic vessels of the lower limbs and the disease is called elephantiasis or filariasis.

Fungi belonging to the genera Microsporium, Trichophyton and Epidermophyton are responsible for ringworms which is one of the most common infectious diseases in man.

Thinking Process

Thymus is the primary lymphoid organ. In thymus gland, immature lymphocytes

differentiate into antigen-sensitive lymphocytes.

Answer

If thymus gland is removed from the body of a person, his immune system will become weak. As a result the person’s body becomes prone to infectious diseases.

Answer

Many microbial pathogens enter the gut of humans along with food. The preventive barriers to protect the body from such pathogens are as follows

(i) the mucus coating of the epithelium lining of the gut helps in trapping microbes entering the body.

(ii) saliva in the mouth and hydrochloric acid in gastric juice secreted by stomach prevent microbial growth.

This type of immunity is innate immunity. It is present from birth and is inherited from parents. The innate immunity remains throughout life.

Thinking Process

Colostrum is the first yellowish milk secreted during initial days of lactation.

Answer

Colostrum contains several antibodies (especially $\lg A$ ) which are absolutely essential for developing resistance for the new-born babies.

Answer

In response to viral infections our body produces glycoproteins called interferons. Such type of barriers of innate immunity is called cytokine barrier. Interferons protect the non-infected cells from further viral infection.

Answer

(A) Antigen binding site Antigen binding site

Structure of an antibody molecule

Answer

The withdrawal symptoms are (i) anxiety (ii) shakiness (iii) nausea (iv) sweating

Answer

During changing weather one is advised to avoid crowded places, because changing seasons are the time when infectious agents are more prevalent as moist condition favoures pathogen to grow fast and people are more vulnerable as their body system is busy in adapting the changing environmental conditions of temperature humidity, etc and they get infected to there pathogen easily.

Answer

Sickle-cell anaemia still persists in the population despite being harmful because this mutation can also be beneficial in certain conditions.

The mutant $\mathrm{Hb}^{5}$ type haemoglobin is found at high frequencies (up to $20 \%$ and above) in the tropical Africa.

It is known that heterozygotes $\left(\mathrm{Hb}^{\mathrm{S}} / \mathrm{Hb}^{\mathrm{A}}\right)$, having both types of haemoglobin show resistance to malarial infection because the body targets the Plasmodium falciparum infected cell for destruction. In contrast, individuals homozygous for normal haemoglobin $\left(\mathrm{Hb}^{\mathrm{A}} \mathrm{H} \mathrm{b}^{\mathrm{A}}\right)$ suffer high mortality rates in early childhood due to malarial infection.

Thus, the allele for sickle cells has been maintained because heterozygotes have a higher reproductive success than either of the two possible homozygotes.

Answer

Lymphoid Organs immune system of human beings consists of lymphoid organs. The organs whereas callid the maturation and proliferation of lymphocytes occurs are called lymphoid organs. Lymphoid organs are of two types. These are

Lymph nodes are small solid structures present at different points along the lymphatic system. They trap the microorganisms or other antigens that enter the lymph and tissue fluid. Antigens trapped in the lymph nodes activate the lymphocytes and produce an immune response.

Answer

Each antibody molecule has four peptide chains, two small called light chains (represented by $\mathrm{L}$ ) and two longer called heavy chains (represented by $\mathrm{H}$ ). Hence, an antibody is represented as $H_{2} L_{2}$.

Answer

When the body encounters a pathogen for the first time, it mounts an immune response by generating antibodies. This response is of low intensity. Subsequent encounter with the same pathogen elicits a highly intensified secondary response.

This is ascribed to the fact that our body appears to have memory of the first encounter. This type of secondary immune response is elicited by memory T-cells, B-cell which keep ready to mount a rapid and vigorous attack as soon as the same pathagen infects the body again.

Answer

The patient is suffering from AIDS. The causative agent is HIV virus, a member of ‘retrovirus group’.

Answer

Differentiate between active immunity and passive immunity

Answer

Differentiate between bening tumour and malignant immunity

Answer

Passive smoking can be equally dangerous because it exposes the persons to the same harmful effect of smoke.

Passive or second hand smoking means being in the same room or place, where some one is smoking and getting exposed to smoke in the surrounding air.

Once inhaled, the smoke can trigger release of mucus in the bronchioles that blocks the airways. This induces coughing. But prolonged exposures can lead to bronchitis emphysema, respiratory tract infections and eventually lung cancer.

Answer

Prevention is always better than cures because some diseases cause extensive damage to the body tissues or organs and have a

(i) Negative effect on their capacity to function.

(ii) Permanent or long term debilitating effect.

(iii) Negative mental and psychological effect.

(iv) Financial burden.

Prevention, therefore is easier and effective, than cure of a disease.

Answer

Preventive measures to control microbial infection include

(i) Maintenance of personal and public hygiene by

(a) Proper cleanliness standards and practices.

(b) Proper disposal of waste.

(c) Periodic cleaning of water reservoirs, etc.

(ii) Control or elimination of vectors that transmit diseases by

(a) Checking water stagnation and garbage accumulation.

(b) Using disinfectants or biological methods to check their breeding and spread.

(iii) Proper immunisation by vaccination, wherever available to control or completely eradicate infectious diseases.

Answer

(a)

(b) The virus is called retro virus because it does not follow the central dogma of biology (DNA $\rightarrow$ RNA $\rightarrow$ Proteins).

Its genetic material is RNA that is transcribed to DNA using enzyme reverse transcriptase.

(c) Yes, the infected cell can survive, while viruses are being replicated and released.

Answer

Diseases which are easily transmitted from one person to another, are called infectious diseases.

For prevention and control of such diseases, maintenance of personal and public hygiene is necessary, for this purpose, some common preventive measurer should be taken as follows

(i) Education People should be educated about communicable disease to protect themselves from such diseases.

(ii) Isolation The infected person should be kept isolated to minimise the spread of infection.

(iii) Vaccination People should get vaccination on time to avoid infection.

(iv) Sanitation The sanitation should be improved to avoid infection from polluted water, contaminated food, etc.

(v) Eradication of Vectors The breeding places of vectors must be destroyed and adult vectors should be killed by suitable methods.

(vi) Sterilisation The patient’s surroundings and articles of use should be completely sterilised to reduce the chances of infection.

Answer

Answer

(a) It represents cannabinoids group of drugs.

(b) Mode of consumption-nasal inhalation or oral in take.

(c) Organs affected-heart and cardiovascular system.

Answer

CT-Computed Tomography. It uses X-rays to generate 3-D images of internal organs. MRI-Magnetic Resonance Imaging. It uses strong magnetic fields and non-ionising radiations to detect pathological and physiological changes in the living tissue accuratily. Both are used in cancer detection.

Answer

Drugs like barbiturates, amphetamines, benzodiazepines, lysergic acid diethylamides (LSD) and other similar drugs, that are normally used as medicines to help patients coping with mental illnesses like depression and insomnia. Morphine is a very effective sedative and painkiller and is very useful in patients who have undergone surgery.

Misuse of plant metabolites fruits and seeds in amounts/frequency more than prescribed for medicinal purposes can impair one’s physical, physiological or functional behaviour creating problem for the society and slowly moves towards the eaternal truth (death).

Answer

Cannabinoids are banned in sports, as athletes misuse these drugs to enhance their performance. But drugs obtained from cannabinoids can cannatnads have, a serious negative effect on their general health and in long term can hamper the normal functioning of organ system.

Answer

Secondary metabolism (also called specialised metabolism) is a term for pathways and metabolites are small molecule produced by metabolism that are not absolutely required for the survival of the organism.

In case of plant, metabolites aid in the growth and development of plants. It also facilitates the primary metabolism.

Answer

Curiosity, need for adventure and excitement and experimentation, constitute common causes, which motivate youngsters towards drug and alcohol use.

The frequent use of drugs/alcohols drive people to take them even when these are not needed, or even their use becomes self-destructive.

Short-term effects of drugs/alcohols

• A relaxing effect
• Lowered inhibitions
• Slow reflexes
• Reduced coordination
• Sensations and perceptions that are less clear

Long-term effects of drugs/alcohols

• Disrupts normal brain development
• Liver damage and cirrhosis of the liver
• Brain cells die, decreasing brain mass
• Stomach and intestinal ulcers and destroyed organs
• Blood pressure increases, causing heart disease, heart attack or stroke
• Male sperm production decreases
• Lower levels of iron and vitamin-B, causing anaemia
• Alcoholism
• Death and
• Fetal alcohol syndrome in unborn children

Answer

Dysentery, cholera and typhoid are more common in crowded settlements because these are infectious diseases and spread from person to person contact. Water gets contaminated with the excreta of infected people and causes the spread of infection to other people.

Answer

Cannabinoids are obtained from the inflorescence of the plant Cannabis sativa. Marijuana, hashish, charas, ganja are some cannabinoids. These chemicals interact with cannabinoid receptors of the body, mainly present in the brain. Cardiovascular system of the body is effected adversly by consuming these substances.

Thinking Process

Allergy is the exaggerated response of the immune system of certain antigens present in the environment.

Answer

In metropolitan cities life style is responsible in lowering of immunity and sensitivity to allergens. More polluted environment like dust in surroundings increases the chances of allergy in children. Some symptoms of allergic reactions are sneezing, watery eyes, running nose and difficulty in breathing.

Answer

The principle of vaccination is based on the property of ‘memory’ of immune system. In vaccination, a preparation of antigenic proteins or inactivated/live but weakened pathogens is introduced into the body. The antigens generate primary immune response by producing antibodies along with memory B-cells and T-cells.

When the vaccinated person is attacked by the same pathogens, the existing memory B-cells and T-cells recognise the antigen and overwhelm the invaders with massive production of lymphocytes and antibodies.

Hepatitis-B vaccine is produced from yeast.

Answer

An abnormal and uncontrolled division of cells is termed as cancer. Genes called cellular oncogenes (c-onc) or proto-oncogens present in normal cells when activated under certain conditions lead oncogenic transformation of the normal cells leading cancer. A cancer cell is different from the normal cell in following ways

Answer

If a person is hypersensitive to certain substance present in the air, he may be allergic to it. Mast cells release certain chemicals, e.g., histamine and serotonin, in response to this substance, that result in allergic reaction.

Precaution taken to prevent such reaction is to avoid the allergens responsible for particular allergy.

Answer

For an organ transplant, it is an advantage to have an identical twin because the organ will have same surface markers and therefore, the recipient’s immune system will not identify it as foreign and will not react against it. In case of different surface markers, the immune system starts a reaction, kills the foreign tissue or rejects it.

Answer

Life style disease are caused by specific food habits, work related posture or exposure to harmful radiations or substances, lack of physical exercise, mental stress, etc.

e.g., cancer, alcoholism, heart disease, etc.

Answer

RNA mutates faster than DNA.

DNA is more stable and also has better repair mechanisms that correct the changes in base pairs as soon as it is introduced.

Answer

The life-cycle of a malarial parasite

Answer

People think that the city life is better than village life. However, there are so many advantages as well as disadvantages of urban life and rural life

Advantages of Urban (city) Life

The city life is more comfortable as there are lot of facilities in the city. There are more opportunities for people to progress their lives and they have more opportunities for making money.

Children living in the city can get a good education, in the town than in the village. When a person falls ill, there are good government and private hospital in the city to get treatment. There are large shopping complexes, banks, offices, cinemas, clubs, hospitals, etc., in and around the city for recreations.

People in the city have better transport facilities than the village. There is electricity, highway, communication, telecommunication, plumb facilities in the city. So, people can lead a comfortable and enjoyable life in the city.

Disadvantages of Urban (city) Life

Although living in the city has many advantages there are some disadvantages too. The cost of living is very high in the city. Goods are expensive, no fresh air and pure water is present. The environment is polluted with dust, smoke, garbage and gases from factories.

Most of the people who live in the city are corrupted, so there are lots of crimes in the city Many thefts and murders often take place in the city.

The city is always busy and noisy. There are a lot of vehicles and people in the road. The streets are dusty and unclean. So, it is hard to lead a healthy life in the city.

Advantages of Rural (village) Life

The people of the village live in unity and peace. The villagers earn money enough for live. very hardly. So, they live in less competition with each other. They have more friends in the community.

The village people always try to protect their traditional habits and culture. The village has clean air and the environment is very beautiful. The village has less noise and rush. So, the pollution is less.

The village do not have lot of vehicles. So, roads are less dangerous for driving or cycling They can get fresh vegetables and fresh fruits. The environment of the village is pleasant and silent and it has scenic beauty.

Disadvantages of Rural (village) Life

People living in rural area have to face many problems like lack of good education, proper medical facilities, transportation, electricity, telecommunication, etc.

Life style affects human health and cause many diseases due to specific food habits, work related posture or exposure to harmful radiation or substances, lack of physical exercise, mental stress, etc. Some life style diseases are cancer, alcoholism, heart diseases, etc.

Answer

The reasons why adolescents and youngsters starts consumption of drugs are

(i) Curiosity of child motivates him/her to do experiment.

(ii) For adventure and excitement.

(iii) Peer group pressure.

(iv) Desire to do more physical and mental work.

(v) To overcome frustration and depression, due to failure in examinations or in other activities.

(vi) Unstable or unsupportive family structures.

The following measures can be taken to avoid drug abuses

(i) Avoid undue pressure on child to perform beyond his/her capability in studies, sports or any other activities.

(ii) Education and counselling are very important to face problem of stress and failure in life.

(iii) Seeking help from parents, elders and peers. This would help the young to share their feelings and concern.

(iv) Looking for danger signs and taking appropriate measures to treat them.

(v) Seeking professional and medical help for de-addiction and rehabilation.

Answer

If a person is addicted to alcohol, it will give rise to some behavioural changes in that person. Alcoholic drinks are costly and most drinkers, because of their selfish habits, deprive their children and other members of the family of the basic needs.

The drinking of alcohol is invariably associated with social crimes and dissolution of moral and cultural inhibitions. Violence and other corrupt practices in the community are often directly or indirectly due to the consumption of alcohol.

Measures that should be taken to overcome the above mentioned problem are

(i) Avoid Undue Peer Pressure Every person has his/her own choice and personality, which should be kept in mind. So he/she should not be pressed unduly to do beyond his/her capacities, in work condition and other in social get together or activities.

(ii) Education and Counselling Helps to overcome the problems, like stresses, disappointments and failure in life. One should utilise a himself/herself energy in some beneficial activities like sports, music, reading, yoga and other extra curricular activities.

(iii) Seeking Help from Parents and Peers In case of minors, whenever, there is any problem, one should seek help and a guidance from parents and peers. Help should be taken from close and trusted friends. This would help young to share their feelings of anxiety and wrong doings.

(iv) Looking for Danger Sings If friends find someone using drugs or alcohol, they should bring this to the notice of parents or teacher so that appropriate measures can be taken to diagnose the illness and the causes. This would help in taking proper remedial steps or treatment.

(v) Seeking Professional and Medical Helps Highly qualified psychologists, psychiatrists and de-addiction and rehabilitation programmes can help individuals who are suffering from drug/alcohol abuse.

If such help is provided to the affected persons, with sufficient efforts and will power, the patient could be completely cured and lead normal and healthy life.

Answer

Early detection of cancer is essential. The methods of cancer detection and diagnosis are as follows.

(i) Biopsy and histo-pathological studies of the tissue/ blood/ bone marrow.

(ii) Tests for increased cell counts (in the case of leukaemia blood cancer).

(iii) Techniques like radiography (use of X-rays), CT (computed tomography) and MRI (Magnetic Resonance Imaging) to detect cancers of the internal organs.

(iv) Detection of cancer specific antigens.

(v) Molecular biology techniques to detect genes in individuals with inherited susceptibility to certain cancers.

The common approaches for treatment of cancer

(i) Surgical removal of tumour.

(ii) Irradiation of tissue to kill cancerous cells.

(iii) Immunotherapy using interferon to boost cancer cell killing.

Answer

Harmful effects of drugs like LSD, barbiturates, are

(i) Anxiety, shakiness, nausea and sweating, loss of mind control.

(ii) Reckless behaviour, vandalism and violence.

(iii) Lack of interest in personal hygiene, fluctuations in weight and appetite.

(iv) Withdrawal, isolation, depression, fatigue, aggressive behaviour.

(v) Social adjustment problems

(vi) Withdrawal symptoms can be severe and life threatening.

(vii) Excessive doses of drugs may lead to coma and death may occur due to respiratory failure, heart failure or cerebral haemorrhage.

Answer

Pulse Polio is an immunisation campaign established by the Government of India in 1995-96 to eradicate poliomyelitis (polio) in India by vaccinating all children under the age of five years orally against polio virus.

This project deals with the ways to fight poliomyelitis through a large scale immunisation programme, co-operating with various international institutions, state governments and Non-Governmental Organisations. In 1995, following the polio eradication initiative of World Health Organisation (1988), India launched Pulse Polio Immunisation Program along with Universal Immunisation Program which aimed at $100 \%$ coverage.

Having mate on unprecedented progress in polio eradication, India is now gearing up to be declared polio free by 2014 by guarding itself against the import of polio virus from neighbouring countries and by boosting routine immunisation.

Oral Polio Vaccine

Oral Polio Vaccine (OPV) is a live-attenuated vaccine, produced by the passage of the virus through non-human cells at a sub-physiological temperature, which produces spontaneous mutations in the viral genome.

OPV also proved to be superior in administration, eliminating the need for sterile syringes and making the vaccine more suitable for mass vaccination campaigns. OPV also provides long lasting immunity than the salk vaccine.

One dose of OPV produces immunity to all India is mainly an agricultura poliovirus serotypes in approximately 50 % of recipients. India is yet to eradicate polio because inspite of many initiatives taken by government, few cases has been reported.

The last reported cases of polio in India was in West Bengal and Gujarat on 13 January 2011. Earlier this year, the World Health Organisation (WHO) had removed India from the list of polio-endemic countries. If no fresh case is reported till 2014, the country will be declared polio free.

July 30, 2013 a nine-month old boy from Navi Mumbai has been found positive for Vaccine-Derived Polio-Virus(VDPV) type 2 and was on ventilator at BJ Wadia Hospital in Parel. This is the fourth such case recorded in the country that year.

In India the main obstacle in the eradication of polio had been the refusal of polio vaccine by certain communities on account of illiteracy and misinformation.

Answer

Recombinant DNA vaccines are made up of a small circular DNA (plasmid) that has very tiny piece of pathogen DNA incorporated in it to produce one or two specific proteins of the pathogen.

This recombinant DNA is introduced in to the bacteria or yeast cells, where it can use cell’s machinery to produce polypeptides of pathogen. These are used as vaccine to trigger a range of immune responses.

Vaccines produced by using this approach allow large scale production. e.g.,

(i) Hepatitis-B vaccine produced from yeast.

(ii) Bird flu DNA vaccine.

Advantages

(i) Recombinant DNA vaccines are advantageous over killed or attenuated vaccines since, they does not get virulent or mutated again as it is seen in case of attenuated vaccines.

(ii) Secondly these are highly pure, specific and elicits strong immune response.