8

Q1. Carcinoma refers to

• 1) Benign tumour of connective tissue
• 2) Malignant tumour of colon
• 3) Malignant tumours of skin or mucous membrane
• 4) Malignant tumour of muscular tissue

Solution

Carcinoma affects the epithelial and glandular tissues which very easily spread to the neighbouring tissues resulting in Malignant tumors.

Q2. Opiate narcotic drugs are:

• 1) Hypnotic
• 2) Antihistamine
• 3) Antianxiety
• 4) Analgesic

Solution

The opiate narcotics are drugs that suppress brain activity and relieve pain which are called as pain killers or analgesics.

Q3. Which of the following vaccines are injected at the age of ,and  Months?

• 1) BCG and DTP-Hib
• 2) Polio and BCG
• 3) BCG and Hepatitis-B
• 4) DTP-Hib and Polio

Solution

A dose of DTP/Hib (Haemophilus influenza type b) vaccine is offered at age ,and  months in children.   This is a combination vaccine which does not contain any live organisms (germs) so cannot cause any of the diseases it is protecting against.

Q4. Retroviruses are implicated as a cause of cancer in humans because they

• 1) May carry cellular proto oncogenes in their genome
• 2) Carry gene for reverse transcription
• 3) Carry RNA as their genetic material
• 4) May carry oncogenes in their genome

Solution

Retroviruses are implicated as a cause of cancer in humans because they may carry cellular proto oncogenes in their genomes.

Q5. The causative agent for amoebiasis is released by the patient in the

• 1) Faeces
• 2) Saliva
• 3) Tears
• 4) Blood

Solution

The causative organism for amoebiasis, Entamoeba histolytica, lives in the large intestine and the lower part of the small intestine of humans and is expelled out of the body through the faeces.

Q6. Which one of the following depresses brain activity and produces feeling of calmness, relaxation and drowsiness?

• 1) Morphine
• 2) Valium
• 3) Amphetamines
• 4) Hashish

Solution

The drug addict when feels calm, relaxed and drowsy, this is due to the intake of sedatives that targets the central nervous system. Valium is a drug that comes in category of benzodiazepines and is a sedative.

Q7. Lung cancer may develop due to

• 1) All of the above
• 2) Calcium fluoride
• 3) Coal mining
• 4) Cement particles

Solution

All the above mentioned substances affect the lungs and may in some instances cause lung cancer.

Q8. Cyclosporine is a drug that is used as:

• 1) Immunosuppressant
• 2) Immuno vaccine
• 3) Anti retro-viral drug
• 4) Immuno-modulator

Solution

Cyclosporin is a powerful immunosuppressive agent that has clinical application in the treatment of autoimmune disorders and used with initial success in recipients of kidney, liver, bone marrow and pancreas transplants.

Q9. Which of the following is used as an anti-sleep drug?

• 1) Betel nut
• 2) Crack
• 3) Amphetamine
• 4) Cocaine

Solution

Amphetamine is a synthetic drug which stimulates the CNS and causes alertness and excitement, thus preventing the individual from falling asleep. Hence, it is commonly used as an anti-sleep drug.

Q10. Short lived immunity acquired from mother to foetus across placenta or through mother's milk to the infants is

• 1) Active immunity
• 2) Innate non-specific immunity
• 3) Passive immunity
• 4) Cellular immunity

Solution

Passive immunity is when ready-made antibodies are directly given to protect the body against foreign antigens which clearly shows the example of colostrum which is secreted during lactation to the foetus who receives some antibodies to protect the infant.

Q11. Electron-beam therapy is a kind of radiation therapy to treat

• 1) Gall bladder stones by normal cells
• 2) Enlarged prostate gland
• 3) Certain types of cancers
• 4) Kidney stones

Solution

Electron beams is a technique where electrons are directed to a tumor site. They have a low energy level and don’t penetrate deeply into the body, so this type of radiation is used most often to treat the skin, tumors, and lymph nodes that are close to the surface of the body.

Q12. Tunnel vision is associated with:

• 1) Drug addiction
• 2) Mental health
• 3) Smoking
• 4) Alcoholism

Solution

Tunnel vision is the loss of peripheral vision that is caused due to alcohol consumption. The vision becomes blurred or double.

Q13. Antigen-binding site in an antibody, is found between:

• 1) Two light chains
• 2) Either between two light chains or between one heavy and one light chain
• 3) One heavy and one light chain
• 4) Two heavy chains

Solution

Antigen-binding site is found between one heavy chain and one light chain.

Q14. Name the two-special types of lymphocytes in humans. How do they differ in their roles in immune response? 

Solution

B-lymphocytes and T-lymphocytes are two types of lymphocytes in humans. B- lymphocytes produce antibodies that can produce response to pathogens. T- lymphocytes help the B-lymphocytes to produce antibodies.

Q15. Cannabis plant is used in the production of:

• 1) Marijuana
• 2) Ganja
• 3) Charas
• 4) All of these

Solution

Cannabis plant are also called as hemp plants whose dried leaves, resins and flowers yield drugs that provides charas, ganja and marijuana.

Q16. Which of the following is the unit of immune system?

• 1) Lymphocyte
• 2) Parasite
• 3) Erythrocyte
• 4) Chondrocyte

Solution

The immune system consists of lymphoid organs in which lymphocytes such as B-cells and T-cells are present.

Q17. Marijuana is extracted from

• 1) Roots of hemp plant
• 2) Cocoa plant
• 3) Ergot fungus
• 4) Dried leaves and flowers of hemp plant

Solution

Bhang, ganja and charas yields from dried leaves, resins and flowers of hemp plants which is Cannabis indica. But marijuana yields from same hemp plants but from different species, Cannabis sativa.

Q18. Drugs which induce dreamy state of consciousness are called:

• 1) Hallucinogens
• 2) Sedatives
• 3) Stimulants
• 4) Barbiturates

Solution

There are drugs that act on central nervous system and affect the feelings, dreams and thought of a person which are called as hallucinogens or psychedelic drugs.

Q19. The sporozoites that cause infection when a female Anopheles mosquito bites a human being are formed in:

• 1) Intestine of human
• 2) Liver of human
• 3) Salivary glands of mosquito
• 4) RBCs of mosquito

Solution

The sporozoites are formed in the intestine of humans that escapes and migrate to the salivary glands of mosquitoes.

Q20. Which of the following diseases are caused by a virus?

• 1) Dysentery and common cold
• 2) Common cold and AIDS
• 3) Ring worm and AIDS
• 4) Typhoid and tuberculosis

Solution

Common cold and AIDS are caused by Myxovirus and HIV, respectively.

Q21. HIV is classified as a retrovirus because its genetic information is carried in

• 1) DNA
• 2) DNA instead of RNA
• 3) Protein coat
• 4) RNA instead of DNA

Solution

HIV is a retrovirus because it contains RNA rather than DNA. It uses a reverse transcriptase to produce DNA from its RNA genome.

Q22. Which of the following is not a lymphoid tissue?

• 1) Appendix
• 2) Spleen
• 3) Tonsils
• 4) Thymus

Solution

Lymphoid tissue begins to accumulate in the appendix shortly after birth and decreases rapidly thereafter and practically disappearing after the age of 60.  During the early years of development, however, the appendix has been shown to function as a lymphoid organ, assisting with the maturation of B lymphocytes and in the production of the class of antibodies known as immunoglobulin A (IgA) antibodies.

Q23. Pethidine is a

• 1) Tranquilliser
• 2) Stimulant
• 3) Hypnotic
• 4) Opiate narcotic

Solution

Pethidine is an opiate narcotic.

Q24. Which of the following drugs is obtained from the fruiting body of the Mexican mushroom Psilocybe mexicana?

• 1) Psilocybin
• 2) Mescaline
• 3) Methylenedioxy methamphetamine
• 4) Phencyclidine piperidine

Solution

Psilocybin is obtained from the fruiting body of the Mexican mushroom Psilocybe mexicana. It is used as a hallucinogenic agent.

Q25. Alcohol is not a food. Comment on the statement.

Solution

The energy produced by oxidation of alcohol is not according to the body needs. Some energy of body is used to expel extra heat out of the body. In addition, the presence of alcohol in body tissues causes some ill effects.

Q26. Many diseases can be diagnosed by observing the symptoms in the patient. Which group of symptoms is indicative of pneumonia?

• 1) Nasal congestion and discharge, cough, sore throat, headache
• 2) High fever, weakness, stomach pain, loss of appetite and constipation
• 3) Constipation, abdominal pain, cramps, blood clots
• 4) Difficulty in respiration, fever, chills, cough, headache

Solution

Pneumonia shows symptoms like difficulty in respiration, fever, chills, cough and headache.

Q27. Passive immunity was discovered by

• 1) Louis Pasteur
• 2) Edward Jenner
• 3) Robert Koch
• 4) Emil von Behring

Solution

Passive immunity is the immunity which is imparted artificially to an individual by introducing antibodies from an organism which has already suffered from the disease. Passive immunity against small pox was discovered by Edward Jenner.

Q28. In malaria, the product released by mosquitoes into blood that causes chill and fever is called:

• 1) Haematin
• 2) Schuffner's dots
• 3) Haemazoin
• 4) Haematoxin

Solution

A toxic substance called haemazoin is released due to rupture of RBCs, which is responsible for the chill and high fever recurring every 3-4 days.

Q29. The disease chikunguniya is transmitted by

• 1) Cockroach
• 2) Aedes mosquitoes
• 3) House flies
• 4) Female Anopheles

Solution

Chikungunya and Dengue are vector-borne diseases that spread through Aedes mosquitoes.

Q30. Which immunoglobulin is largest in size?

• 1) Ig D
• 2) Ig A
• 3) Ig E
• 4) Ig M

Solution

Ig M is the largest immunoglobulin that possesses 900 kDa molecular weight with IgA being 150 kDa, IgE being 190 kDa and IgD is not yet identified.

Q31. A person showing unpredictable moods, outbursts of emotion, quarrelsome behaviour and conflicts with others is suffering from:

• 1) Additive disorder
• 2) Mood disorders
• 3) Borderline personality disorder
• 4) Schizophrenia

Solution

Borderline personality disorder leads to significant distress or impairment in social, work or other areas of functioning those results in quarrelsome behavior and unstable relationships.

Q32. Which of the following is associated with smoking?

• 1) Emphysema
• 2) All of these
• 3) Lung cancer
• 4) Bronchitis

Solution

Smoking causes various diseases that are injurious to health which include bronchitis, lung cancer, emphysema etc.

Q33. In malignant tumors, the cells proliferate, grow rapidly and move to other parts of the body to form new tumors. This stage of disease is called:

• 1) metagenesis
• 2) teratogenesis
• 3) metastasis
• 4) mitosis

Solution

Metastasis is a stage of cancer is a cancer that has spread from the part of the body where it started to other parts of the body. 

Q34. (i) Why is tobacco smoking associated with rise in blood pressure and emphysema (oxygen deficiency in the body)? Explain. (ii) How does the moderate and high dosage of cocaine affect the human body?  

Solution

(i) Tobacco has nicotine that stimulates the release of adrenaline and nor-adrenaline, which raise blood pressure. Smoking tobacco releases carbon monoxide, which reduces the concentration of haem-bound oxygen. This causes emphysema. (ii) Cocaine has a potent stimulating action on central nervous system producing a sense of euphoria and increased energy. Excessive dosage of cocaine causes hallucinations.

Q35. Which one of the following is not a property of cancerous cells whereas the remaining three are?

• 1) They compete with normal cells for vital nutrients
• 2) They do not remain confined in the area of formation
• 3) They show contact inhibition
• 4) They divide in an uncontrolled manner

Solution

Cancerous cells do not have property of inhibition.

Q36. Mention the useful as well as the harmful drug obtained from the latex of Poppy plant. 

Solution

Useful drug obtained from poppy plant is morphine and harmful drug obtained is heroin.

Q37. The drug used to increase cardiovascular effects in human beings is:

• 1) Barbiturate
• 2) Benzodiazepine
• 3) Cocaine
• 4) Insulin

Solution

Vasoconstrictor drugs like cocaine contract the smooth muscle in blood vessels, which causes the vessels to constrict and also increases cardiovascular effects.

Q38. Ascaris is most commonly found in:

• 1) Men
• 2) (A) and (B)
• 3) Children
• 4) Women

Solution

Ascaris lives in the small intestine. It attacks children because they become infected by ingesting soil.

Q39. AIDS is caused by HIV. Among the following, which one is not a mode of transmission of HIV?

• 1) Shaking hands with infected persons
• 2) Transfusion of contaminated blood
• 3) Sharing the infected needles
• 4) Sexual contact 'with infected persons

Solution

Shaking hands with infected persons is not a mode of transmission of HIV AIDS. Transfusion of contaminated blood, sharing the infected needles and sexual contact with infected persons is the main mode of transmission of HIV.

Q40. LSD is:

• 1) Lysergic acid dimethylamide
• 2) Lysing dimethylamide
• 3) Lysing diethylamide
• 4) Lysergic acid diethylamide

Solution

Lysergic acid diethylamide (LSD) are drugs that are used as medicines to help patients cope with mental illness like depression and insomnia are used as drug abuse.

Q41. In what different forms is the tobacco used? Name its addicting component. 

Solution

Tobacco is chewed, smoked or snuffed. Its addicting component is nicotine.

Q42. What are carcinogens? Name any two carcinogens. 

Solution

Carcinogens are physical, chemical or biological cancer causing agents. Two carcinogens are X-rays and aflatoxin.

Q43. Anti venom against snake poison contains:

• 1) Antibodies
• 2) Antigens
• 3) Antigen-antibody complexes
• 4) Enzymes

Solution

Snake anti-venom consists of venom neutralizing antibodies from host animals such as horse or sheep. The host animal is hyperimmunized to one or more snake venoms, a process which creates an immunological response that produces large numbers of neutralizing antibodies against various components (toxins) of the venom.

Q44. Consumption of alcohol may lead to:

• 1) Accumulation of acetaldehyde in liver
• 2) Synthesis of fat in liver
• 3) All of the above
• 4) Lowering of blood glucose level of the body

Solution

Consumption of alcohol has adverse effects on nervous system, stomach, liver, heart, kidneys etc. It also decreases glucose level in the blood called as alcoholic hypoglycaemia.

Q45. Japanese encephalitis is transmitted by

• 1) Tse tse fly
• 2) Sand fly
• 3) Housefly
• 4) Mosquito

Solution

Japanese Encephalitis virus is transmitted to humans through the bite of infected Culex species mosquitoes, particularly Culex tritaeniorhynchus.

Q46. Which one of the following is a stimulant?

• 1) Opium
• 2) Heroin
• 3) Cocaine
• 4) LSD

Solution

Cocaine makes a person more wakeful, alert and cause excitement; so they are called as stimulants.

Q47. In India, a special organisation set up to help AIDS patients and to fight problems related to AIDS is

• 1) NISCO
• 2) AIIO
• 3) NACO
• 4) NARCO

Solution

NACO (National AIDS Control Organisation) is a special organisation set up to help AIDS patients and to deal with problems related to the disease.

Q48. After drinking alcohol, a person walks clumsily because the alcohol affects his:

• 1) Medulla oblongata
• 2) Spinal cord
• 3) Cerebellum
• 4) Cerebrum

Solution

After drinking alcohol, first of all it affects cerebrum in which the person loses judgement, will power and self control. But when the drinker walks clumsily and dizzy, cerebellum gets involved.

Q49. What is contact inhibition in the normal cells of the body? What are the consequences when this property is lost by these cells? 

Solution

Normal cells show the property of contact inhibition which checks their uncontrolled growth and division; however, in cancer cells, this property of contact inhibition is lost and the cells undergo uncontrolled growth and division which leads to tumor formation.

Q50. Name an opioid drug and its source plant. How does the drug affect the human body? 

Solution

Heroin is an opioid drug derived from latex of poppy plant, Papaver somniferum. Heroin acts as depressant and it causes drowsiness and lethargy decreasing the body functions.

Q51. Which is the drug-yielding part of the plant Papaver somniferum?

• 1) Stem
• 2) Dried seeds
• 3) Dried leaves
• 4) Latex of unripe fruit

Solution

The latex of the unripe fruits of Papaver somniferum yields opium and its derivatives such as morphine, codeine and heroin.

Q52. Which cell secretes antibody?

• 1) Eosinophils
• 2) Neutrophils
• 3) Lymphocytes
• 4) Monocytes

Solution

Lymphocytes such as B-cells secrete antibodies.

Q53. Cancerous cells can be easily destroyed by radiation because of

• 1) Lack of oxygen
• 2) Rapid cell division
• 3) Lack of nutrients
• 4) Fast nutrition

Solution

The ability of radiation to kill cells is high when the cells are rapidly dividing. Because cancerous cells possess the property of rapid cell division, they are easily destroyed by radiation.

Q54. Passive immunity can be obtained by injecting:

• 1) Vaccination
• 2) Antibiotics
• 3) Antigens
• 4) Antibodies

Solution

With injection of antibodies directly to protect the body against foreign agents, passive immunity is attained.

Q55. Select the correct statement from the ones given below:

• 1) Morphine is often given to persons who have undergone surgery as a pain killer
• 2) Barbiturates when given to criminals make them tell the truth
• 3) Chewing tobacco lowers blood pressure and heart rate
• 4) Cocaine is given to patients after surgery as it stimulates recovery

Solution

After surgery, morphine is given in small doses to relieve pain and induce sleep.

Q56. (i) What is meant by addictive disorder? (ii) Name any two opiate narcotics. (iii) Mention any two ways how opiate narcotics affect human body.

Solution

(i) The disorder with physical or psychological need for a habit-forming substance, such as a drug or alcohol is called addictive disorder. (ii) Heroin and morphine are two opiate narcotics. (iii) Two ways of affecting human body by opiate narcotics- suppresses the brain function and it acts as a depressant.

Q57. Antigens are present:

• 1) On nuclear membrane
• 2) On the cell surface
• 3) Inside cytoplasm
• 4) Inside nucleus

Solution

Antigens are found on the cell membrane of every cell, and help to distinguish 'self' cells from 'non self' cells.

Q58. Antigenic determinant sites bind to which portion of an antibody molecule? (1) Light chain  (2) Heavy chain   (3) Intermediate chains (4) Plasma cells

• 1) 1 and 3 are correct
• 2) 2 and 4 are correct
• 3) 1, 2, 3 are correct
• 4) 1 and 2 are correct

Solution

Antigenic determinant sites bind to light chain and heavy chain of an antibody molecule.

Q59. The function of IgE is

• 1) Stimulation of complement system, passive immunity to foetus
• 2) Protection from inhaled/ingested pathogens
• 3) Mediate in allergic response
• 4) Activation of B-cells

Solution

An allergic response mounts significant IgE responses only as a defense against parasitic infections.

Q60. Write two examples of carcinogens. 

Solution

Ultra-violet rays and X-rays are two examples of carcinogens.

Q61. Coffee plant belongs to the family

• 1) Rubiaceae
• 2) Theaceae
• 3) Cactaceae
• 4) Moraceae

Solution

Coffee plant (Coffea arabica) belongs to the Rubiaceae family of plants.

Q62. Antibodies are produced by:

• 1) Monocytes
• 2) Phagocytes
• 3) T-cells
• 4) B-cells

Solution

Lymphocytes such as B-cells secrete antibodies.

Q63. (i)Why is using tobacco in any form injurious to the health? Explain. (ii)What are hallucinogens? Give their two examples. Mention their clinical use, if any. 

Solution

(i)Tobacco in any form is injurious to health because- (a) Smoking of tobacco is associated with cancers of lung, urinary bladder, coronary heart disease, gastric ulcer etc. (b) Smoking increases carbon monoxide content in blood and reduces the concentration of haem-bound oxygen, causing oxygen-deficiency in the body. (c) Oral cancer is due to chewing of tobacco etc. (d) Nicotine, the main content of tobacco stimulates adrenal gland to release adrenaline and nor-adrenaline into blood which raises the blood pressure and increases heart beat. (ii) Hallucinogens are a class of psychedelic drugs which affect cerebrum and sense organs to alter thought, feeling and perception. Two examples are lysergic acid diethyl amides (LSD) and methylenedioxy methamphetamine (MDMA). Clinically, they are used to treat depression and insomnia.

Q64. Each immunoglobin has two heavy chains and two light chains, the antigen binding is present in:

• 1) Variable region of light chain
• 2) Variable region of heavy chain
• 3) Variable region of both heavy and light chains
• 4) Variable region of light chain

Solution

The antigen binding site is present in variable region of both heavy and light chains.

Q65. Formation of antibodies within our body is called:

• 1) Innate immunity
• 2) Passive immunity
• 3) Acquired immunity
• 4) Active immunity

Solution

When a host is exposed to antigens, antibodies are formed inside the host body which is called as active immunity

Q66. Both sickle cell anaemia and Huntington's chorea are:

• 1) Bacterial diseases
• 2) Viral diseases
• 3) Pollution-related diseases
• 4) Congenital diseases

Solution

Sickle cell anaemia and Huntington’s chorea are congenital diseases that occur at birth or even before birth. The incidence is 2~5% in newborn.

Q67. State two different roles of spleen in the human body. 

Solution

Spleen is the secondary lymphoid organ that stores lymphocytes and act as reservoir to store erythrocytes.

Q68. Explain three methods of treatment of cancer. 

Solution

Three methods of treatment of cancer are- (i) Surgery- The tumor cells are removed with the help of surgery to check the spread of cancerous cells. (ii) Radiation therapy- A lethal irradiation of tumor cell is done, taking proper care of the normal tissues surrounding the tumor mass. (iii) Chemotherapy- Cancerous cells are killed by several chemotherapeutic drugs. These drugs exhibit side effects such as hair loss and anaemia.

Q69. Metastasis is associated with

• 1) Benign tumor
• 2) Malignant tumor
• 3) Neoplasm
• 4) Crown gall tumor

Solution

Metastasis is a stage of cancer is a cancer that has spread from the part of the body where it started to other parts of the body. There are some cells which grow very rapidly, invading and damaging the surrounding normal tissues which are called as malignant tumors.

Q70. Diseases are broadly grouped into infectious and non- infectious diseases. In the list given below, identify the infectious diseases: (i) Cancer  (ii) Influenza (iii) Allergy  (iv) Small pox

• 1) (ii) and (iii)
• 2) (iii) and (iv)
• 3) (i) and (ii)
• 4) (ii) and (iv)

Solution

Diseases that are transmitted from one person to another are infectious diseases. Influenza is a type of common cold that is transmitted through air by sneezing and cough. Allergy also spreads by transmission through air.

Q71. Plague is caused by

• 1) Vibrio comma
• 2) Campylobacter
• 3) Yersinia pestis
• 4) Mycobacterium leprae

Solution

Yersinia pestis is the causative organism for plague.

Q72. ELISA is used to detect viruses where the key reagent is

• 1) DNA probe
• 2) RNAse
• 3) Catalase
• 4) Alkaline phosphatase

Solution

ELISA is used to detect AIDS. Enzymes used for labelling in the test include horse radish peroxidase, alkaline phosphatase and β-galactosidase.

Q73. Characters of acquired immunity are:

• 1) All of the above
• 2) Differentiate between self and non-self
• 3) Specificity
• 4) Retains memory

Solution

Acquired immunity is the immunity that our body gains over time, similar to how an individual gains knowledge over time. The major characteristics are-   (i)Our body has the ability to recognize and differentiate various pathogens. It has a specific action for each type of pathogen.   (ii)Our immune system remembers each immunological encounter in our body—once our body is invaded by a pathogen, it creates a specific response to that germ and eliminates it. (iii)It is able to tell apart the cells from our own body and other foreign particles or foreign cells i.e. self and non-self cells.

Q74. Where will you look for the sporozoites of the malarial parasite?

• 1) Spleen of infected humans
• 2) Red blood corpuscles of human suffering from malaria
• 3) Salivary glands of freshly moulted female Anopheles mosquito
• 4) Saliva of infected female Anopheles mosquito

Solution

The sporozoites find their way into the blood of a healthy man along with the salivary secretion of an infected female Anopheles mosquito.

Q75. Cervical cancer can be caused by

• 1) Herpes simplex virus
• 2) Human papilloma virus
• 3) Chlamydia sp.
• 4) Salmonella sp.

Solution

Cervical cancer occurs when abnormal cells on the cervix grow out of control. Cervical cancer is caused by both Herpes simplex virus (HSV) and Human papilloma virus (HPV).

Q76. At which stage of HIV infection does one usually show symptoms of AIDS?

• 1) Within 15 days of sexual contact with an infected person
• 2) When the infecting retrovirus enters host cell
• 3) When HIV replicates rapidly in helper T-lymphocytes and damages larger number of this
• 4) When viral DNA is produced by reverse transcription

Solution

The causative HIV retrovirus enters helper T-Iymphocytes, replicates and produce progeny viruses, thus reducing the number of helper T- cells which stimulate antibody production by B- cells, thereby showing the primary symptoms like fever, swollen throat, muscle and joint aches.

Q77. Name the plant source of the drug popularly called "smack'. How does it affect the body of the abuser?

Solution

The plant source of “smack” drug is poppy plant or Papaver somniferum. Smack is a depressant and slows down body functions.

Q78. Name the group of viruses responsible for causing AIDS in humans. Why are these viruses so named?

Solution

AIDS is caused by HIV which belongs to retroviruses. These are so called as they can cause reverse transcription in the presence of enzyme reverse transcriptase.

Q79. Marijuana and charas are

• 1) Depressant
• 2) Hallucinogens
• 3) Sedative
• 4) Stimulant

Solution

Marijuana and charas are drugs which change thoughts, feelings and perceptions because it has strong effect on cerebrum and sense organs. Therefore they are called hallucinogens.

Q80. A person shows the production of interferon in the body. Which disease could the individual be suffering from?

• 1) Measles
• 2) Typhoid
• 3) Malaria
• 4) Tetanus

Solution

Interferons are produced in response to viral infections. Because measles is the only mentioned viral disease, the individual is likely to be suffering from it.

Q81. What type of virus causes AIDS? Name its genetic material. 

Solution

Retrovirus causes AIDS and RNA is its genetic material.

Q82. (i)Why does a doctor administer tetanus antitoxin and not a tetanus vaccine to a child injured in a roadside accident with a bleeding wound? Explain. (ii)Describe the role of lymph nodes in providing immunity. 

Solution

(i) Tetanus is caused by a microbe which has a deadly and fast action. Action of vaccine is slow which becomes fatal. Therefore, antitoxins are administered which neutralize the effect of the bacterial toxin. (ii) Lymph nodes trap microorganisms. These trapped antigens activate lymphocytes present in the lymph and cause an immune response.

Q83. Which type of cancer affects lymph nodes and spleen?

• 1) Sarcoma
• 2) Lymphoma
• 3) Leukemia
• 4) Carcinoma

Solution

Lymph nodes and spleen are lymphoid organs. So lymphomas are the cancers of the lymphatic tissues. 

Q84. Define proto-oncogenes.

Solution

Inactive cancer causing genes are called proto-oncogenes.

Q85. Damage to thymus in a child may lead to:

• 1) Loss of antibody-mediated immunity
• 2) A reduction in stem cell production
• 3) Loss of cell-mediated immunity
• 4) A reduction in haemoglobin content of blood

Solution

Damage to thymus won’t cause extreme damage to the immunity but it may cause immune deficiency due to antibody-mediated immunity because it produce circulating antibodies in response to the presence of a foreign substance and recognize the substance upon exposure.

Q86. The chemical test that is used for diagnosis of typhoid is:

• 1) PCR-Test
• 2) ELISA-Test
• 3) Widal-Test
• 4) ESR-Test

Solution

Widal test is a test of blood serum that uses an agglutination reaction to diagnose typhoid fever. 

Q87. ‘Smack’ is a drug obtained from the

• 1) Latex of Papaver somniferum
• 2) Flowers of Dhaiura
• 3) Fruits of Erythroxyl coca
• 4) Leaves of Cannabis sativa

Solution

Smack is a by-product obtained from opium which is in turn derived from milky latex of Papaver somniferum. Smack is also called as “brown sugar”. Its chemical name is diacetylmorphine hydrochloride.

Q88.  Differentiate between benign tumor and malignant tumor.

Solution

 Benign Tumor Malignant Tumor (i) These remain confined in the organ affected. (i) These spread from one organ to other organs of the body. (ii) These are enclosed in a connective tissue sheath. (ii) These are not enclosed in a connective tissue sheath. (iii) These have less growth rate. (iii) These have rapid growth rate. (iv) Cancer cells are more adhesive. (iv) Cancer cells are less adhesive. (v) No metastasis occurs. (v) Metastasis is generally present.  

Q89. A boy of ten years had chicken pox. He is not expected to have the same disease for the rest of his life. Mention how it is possible.

Solution

The boy produces antibodies when he encounters for the first time that result in memory of the first encounter to protect the body in future.

Q90. It was diagnosed by a specialist that the immune mechanism of the body of a patient has been suppressed. Name the disease the patient has been suffering from and the microbe responsible for it. Which part of the immune system does it affect and in what manner?

Solution

The patient is suffering from Acquired Immuno Deficiency Syndrome (AIDS). The causal organism is Human Immunodeficiency Virus (HIV). HIV infects Helper T-cells. HIV enters Helper T-cells where it replicates and produces progeny viruses. The progenies liberated by lysis of host T-cells attack other Helper T-cells. Repeated attacks result in progressive decrease in the number of T-cells and thus reducing immunity.

Q91. What bad effect has tobacco on respiratory system? Name two toxic substances present in tobacco.

Solution

Tobacco smoke causes inflammation of bronchi called bronchitis and inflammation of lung alveoli called emphysema. Two toxic substances present in tobacco are nicotine and carbon monoxide.

Q92. Write the source and the effect on the human body of the following drugs: morphine, cocaine, marijuana.

Solution

(i) Morphine is obtained from poppy plant Papaver somniferum. It binds to specific opioid receptors present in central nervous system and gastrointestinal tract. (ii) Cocaine is obtained from coca plant Erythroxylum coca. It interferes with the transmit of the neurotransmitter, dopamine. (iii) Marijuana is obtained from Cannabis sativa. It affects the cardiovascular system of the body.

Q93. High fever, loss of appetite, stomach pain and constipation are some of the symptoms seen in a patient. How would the doctor confirm that the patient is suffering from typhoid and not amoebiasis? 

Solution

By performing Widal test, the doctor can confirm that the patient is suffering from typhoid and not amoebiasis.

Q94. Why do sports persons often fall a victim to cocaine addiction? 

Solution

Cocaine has a potent stimulating action on central nervous system, producing a sense of euphoria and increased energy. Therefore, certain sports persons misuse it to enhance their performance.

Q95. Recently chikungunya cases were reported from various parts of the country. Name the vector responsible.

Solution

Chikungunya is spread through Aedes mosquitoes which is a vector-borne disease.

Q96. List the specific symptoms of pneumonia. Name the causative organism. 

Solution

Specific symptoms of pneumonia are fever, cough, headache and chills. The causative organisms are Streptococcus pneumoniae and Haemophillus influenzae.

Q97. Name the type of cells the AIDS virus first enters into after getting inside the human body. Explain the sequence of events that the virus undergoes within these cells to increase their progeny. 

Solution

HIV inside the human body first attacks Helper T-cells of immune system. RNA and reverse transcriptase enter inside the Helper T-cells. RNA synthesizes the DNA by reverse transcription. DNA copy of HIV binds host cell’s DNA to form prophage and transcribes a large number of RNA molecules, each of which gets surrounded by protein coat to form HIV virus.

Q98. What is cancer? How is a cancer cell different from normal cell? How do normal cells attain cancerous nature? 

Solution

An abnormal and uncontrolled division of cells is termed as cancer.  Cancer Cell  Normal Cell (i) Cancer cells divide in an uncontrolled manner. (i) Normal cells divide in a controlled manner. (ii) The cells do not show contact inhibition. (ii) These cells show contact inhibition. (iii) Lifespan is indefinite. (iii) There is a definite lifespan. The growth and differentiation of cells is highly controlled and regulated. The normal cells show a property called contact inhibition. The surrounding cell inhibits uncontrolled growth and division of cells. The normal cells lose this property and become cancerous cell giving rise to masses of cells called tumors. Transformation of normal cells into cancerous cells is induced by physical, chemical and biological agents that are called carcinogens.

Q99. How does smoking cause oxygen deficiency in body?

Solution

Carbon monoxide present in tobacco smoke binds haemoglobin of RBCs faster than oxygen thus decreasing the oxygen- carrying capacity of haemoglobin.

Q100. Generally lung cancer patients are heavy smokers. Why?

Solution

Benzopyrene and Nitrosodimethylene present in tobacco are carcinogenic in nature and cause lung cancer.

Q101. Name the type of cells the AIDS virus enters into after getting in the human body.

Solution

HIV enters into Helper T- cells reducing the number in the body of the infected person.

Q102. (i)What are allergens? How do human beings respond to them? (ii)What is the basic principle of vaccination? How do vaccines prevent microbial infections? Name the organism from which hepatitis B vaccine is produced. 

Solution

(i) Allergens are substances which act as weak antigens and cause inappropriate and excessive immune response. Allergens initiates harmful antibody formation which in turn binds to the receptors on the mast cell. The mast cell releases chemicals sucha as histamines, which in turn causes inflammation of the mucous membranes. (ii) Principle of vaccination is based on the property of memory of immune system. In vaccination, a preparation of antigenic proteins of pathogens but weakened pathogens is introduced into the body. The antigens generate primary immune response by producing antibodies along with B-cells and T-cells. When the vaccinated person is attacked by the same pathogens, the existing memory B- cells and T-cells recognize the antigen and put a strong effect on the invaders with massive production of lymphocytes and antibodies. Hepatitis B vaccine is produced from yeast. 

Q103. (i)What is a vaccine? Give an example of a vaccine produced by recombinant DNA technology. (ii)Name the disease against which DPT vaccine develops immunity? 

Solution

(i)An inoculation stimulating the production of antibodies in the body is called vaccine. An example of vaccine produced by recombinant DNA technology is Hepatitis B that was produced from yeast. (ii) DPT vaccine develops immunity against diphtheria, pertusis and tetanus.

Q104. Name the type and give the effect of the following drugs in human. (i) LSD  (ii) Morphine (iii) Barbiturates.

Solution

(i) Lysergic Acid diethylamide is a hallucinogen. It affects the cerebrum and sense organs, changing the feeling, thoughts and perceptions of an individual. (ii) Morphine is an opiate narcotic. It suppresses the normal function of brain and relieves intense pain but temporarily. (iii) Barbiturates are sedative drugs and tranquilizers. It suppresses brain’s activity and creates a feeling of relaxation, drowsiness and sleepiness.