Biology Question Bank – 35 MCQs on “Growth, Regeneration, Ageing and Death” – Answered!

(b) Rh+ man and Rh– woman

(c) Rh man and Rh+ woman

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(d) Rhr man and Rh+ woman.

Answer and Explanation:

1. (b): Rh factor plays a crucial role in child’s birth born out of a marriage between Rlr woman and a Rh+ man. In such a case, the mother becomes sensitive while carrying a first Rh+ child within her womb. The reason for such sensitivity is that some of the RBCs from the developing embryo get into the blood stream of the mother during development, causing her to produce anti-Rh antibodies.

In fact, the first child of such parents is nearly normal and is delivered safely. However, if such a mother gets pregnant again, the subsequent Rh+ foetuses will be exposed to the anti-Rh antibodies produced by the mother. As a result serious damage to the red blood cells of the developing embryo will occur causing haemolytic disease of the newborn (HDN) or erythroblastosis foetalis. This disease leads to the death of the developing embryo before birth or after parturition.

2. Give the correct matching of causative agent/germ and disease

(a) Anopheles – malaria

(b) Leishmania – Slkeeping sickness

(c) Glossina – Kala-azar

(d) Wuchereria – Filariasis.

Answer and Explanation:

2. (d): Wuchereria bancrofti is a parasitic filarial nematode worm spread by a mosquito vector. It is one of the three parasites that cause lymphatic filariasis. Elephantiasis can result if the infection is left untreated. Limited treatment modalities exist and no vaccines have been developed.

Malaria is caused by protozoan parasites of the genus Plasmodium. Malaria parasites are transmitted by female Anopheles mosquitoes. Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. Kala-azar is caused by Leishmania (protozoan) and is transmitted by sand fly.

3. A cell-coded protein that is formed in response to infection, with most animal viruses, is called

(a) histone

(b) antibody

(c) interferon

(d) antigen.

Answer and Explanation:

3. (c): Interferons are proteins that increase the resistance of a cell to attack by viruses by unmasking genes that synthesize antiviral proteins. In humans, three groups of interferons have been discovered: a-interferons from white blood cells; P-interferons from connective tissue fibroblasts; and y-interferons from lymphocytes. Interferons do not act directly to inhibit viral multiplication; rather, it induces the formation of a second protein, called antiviral protein, which is atrue inhibitor.

Interferon induces antiviral protein synthesis not only in the cell in which it is itself synthesised, but also in the surrounding cells to which it diffuses. Histone is a group of water-soluble proteins found in association with the DNA of plant and animal chromosomes. Antibody is a protein produced by lymphocytes in response to entry into the body of a foreign substance (antigen) is order to render it harmless.

4. Which one of the following does correctly match a sexually transmitted disease with its pathogen?

(a) syphilis- Treponema pallidum

(b) gonorrhoea-Entamoeba histolytica

(c) urethritis-Bacillus anthracis

(d) softsore-Bacillus brevis.

Answer and Explanation:

4. (a): Syphilis is caused by a spirochete (spiral bacterium) Treponema pallidum. The symptoms of syphilis occur in three stages. The first stage usually consists of a painless lesion called a chance at the organism’s site of entry.

The second stage begins as the organism enters the blood. Symptoms such as fever, flu like illness, a skin rash, hair loss, and swollen joints may come and go over a period of several years. In the third stage permanent brain damage, heart disease, and blindness often occurs. Gonorrhoea is caused by Neisseria gonorrhoeae. Urethritis is inflammation of urethra.

5. A metastatic cancerous tumour is termed ‘sarcoma’ if the disorder is in

(a) fibroblasts

(b) circulatory system

(c) immune system

(d) epithelial cells.

Answer and Explanation:

5. (a): Fibroblasts are the cells present in connective tissue. Sarcomas are cancers that are located in connective and muscular tissues derived from mesoderm. Thus, they include the cancers of bones, cartilages, tendons, adipose tissue, lymphoid tissue and muscles.

6. Rickettsia form a group under

(a) viruses

(b) bacteria

(c) fungi

(d) a category between viruses and bacteria.

Answer and Explanation:

6. (b): Rickettsia is a very small coccoid or rod-shaped gram-negative bacterium belonging to the phylum Proteobacteria. With one exception, rickettsias are obligate parasites, being unable to reproduce outside the cells of their hosts. Rickettsias can infect such arthropods as ticks, fleas, lice, and mites, through which they can be transmitted to vertebrates, including humans.

7. The blood cancer is known as

(a) haemolysis

(b) haemophilia

(c) leukaemia

(d) thrombosis.

Answer and Explanation:

7. (c): The normal count of WBCs is 5000 to 10000 per cubic millimeter of blood. Leukaemia is characterized by abnormal increase of WBCs count, 20000-1000000/ mm3 due to their increased formations in the bone marrow. Haemolysis is breakdown of RBCs. Haemophilia is a disease in which blood clots slowly. Thrombosis is a clot formation inside the blood vessels.

8. Which one of the following pairs is not correctly matched?

(a) syphilis – Trichnris trichiura

(b) sleeping sickness – Trypanosoma gambiense

(c) dengue fever – arbovirus

(d) plague – Yersinia pestis.

Answer and Explanation:

8. (a): Syphilis is caused by a spirochete (spiral bacterium) Treponema pallidum. The symptoms of syphilis occur in three stages. The first stage usually consists of a painless lesion called a chance at the organism’s site of entry. The second stage begins as the organism enters the blood. Symptoms such as fever, a flu like illness, a skin rash, hair loss, and swollen joints may come and go over a period of several years. In the third stage permanent brain damage, heart disease, and blindness often occurs.

Sleeping sickness is a disease of tropical Africa caused by the presence in the blood of the parasitic protozoan, Trypanosoma gambiense. Plague is an epidemic disease of rats which is transmitted to humans by rat fleas. Dengue is a disease transmitted to humans by mosquito, Aedes aegypti.

9. Which one of the following diseases is due to an allergic reaction?

(a) enteric fever

(b) skin cancer

(c) goitre

(d) hay fever.

Answer and Explanation:

9. (d): Hay fever is a form of allergy due to the pollen of grasses, trees, and other plants, characterized by inflammation of the membrane lining the nose and’ sometimes of the conjunctiva. The symptoms of sneezing, running or blocked nose and watering eyes are due to histamine released by the mast cells.

10. Which of the following causes plague?

(a) Trichinella spiralis

(b) Salmonella typhimurum

(c) Yersinia pest is

(d) Leishmania donovani.

Answer and Explanation:

10. (c): Plague is an acute epidemic disease of rats and other wild rodents caused by the bacterium Yersinia pestis, which is transmitted to humans by rat fleas. Headache, fever, weakness, aching limbs, and delirium develop and are followed by acute painful swellings of the lymph nodes.

Bleeding under the skin, producing black patches, can lead to ulcers, which may prove fatal. Treatment with tetracycline, streptomycin, and chloramphenicol is effective. Trichinosis is caused by Trichinella spiralis which lives as an endoparasite in human intestine. Salmonella lyphimurum causes enteric fevers. Leishmania donovani causes kala-azar.

11. Which of the following pair of diseases is caused by virus?

(a) rabies, mumps

(b) cholera, tuberculosis

(c) typhoid, tetanus

(d) AIDS, syphilis.

Answer and Explanation:

11. (a): Mumps is an infectious disease causing fever, difficulty in opening the mouth and painful swelling of the parotid glands which lie just below the lobe of the ears. It is caused by a Paramyxovirus, which comes out in the saliva of the infected person.

Rabies (Hydrophobia) is caused by a virus named as rabies virus. It is introduced in the body by the bite of rabid (mad) dogs usually. Fear of water is the most important characteristic symptom of this disease. Other symptoms are saliva from the mouth, severe headache, high fever, alternating periods, of excitement and depression, inability to swallow even fluids due to choked throat. The virus destroys the brain and spinal cord. Rabies is 100% fatal.

Cholera and tuberculosis are bacterial diseases caused by Vibrio cholerae and Mycobacterium tuberculosis respectively. Typhoid and tetanus are bacterial diseases caused by Salmonella typhi and Clostridium tetani respectively. AIDS is caused by HIV (human immunodeficiency virus). Syphillis is caused by spirochaete Treponema pallidum.

12. Which of the following will be curable in next two decades?

(a) tuberculosis

(b) cancer

(c) poliomyelitis

(d) none of these.

Answer and Explanation:

12. (b): Cancer may be curable in next two decades. The completion of the human genome is causing profound changes in thinking and direction of biomedical research. Cancer is caused by malfunctioning of genes, either through activation of cancer causing oncogens, or through inactivation of tumor suppressor genes.

By comparing the active genes in the tumor to that of normal cells, the genes causing the cancer can be determined. Side by side there is a huge progress in the field of genetic engineering and biotechnology. All these aspects give us hope that cancer may be curable in next two decades. TB is curable by taking anti tubercular drugs and polio may be on the verge of eradication if the pulse polio programme succeeds.

13. Diphtheria is caused by

(a) nematodes

(b) bacteria

(c) virus

(d) none of these.

Answer and Explanation:

13. (b): Diphtheria is caused by Corynebacterium diphtheriae (bacteria) usually affecting children upto five years of age. It may start as sore throat, chills with mild fever, sometimes vomiting and headache. Throat and or tonsils show a grey membrane which may spread down and cause hoarseness and difficulty in breathing.

Nose may be affected giving rise to a blood-tinged nasal discharge from one nostril. If the disease is not treated early and properly the toxin produced by the germs affects the heart and the nervous system, and proves fatal. The germs are present in the discharges from the nose and throat of patients and also of healthy people who act as the “carriers”.

The patients and the carriers spread the disease through acts like kissing, talking, coughing and sneezing. Incubation period is of 2 – 5 days. The patient should be kept in a well-ventilated room if there is no isolation hospital in the town. The most important preventive measure-against this disease is that all babies should be immunised within the first six weeks of birth using DPT vaccine.

14. Which of the following diseases is now considered completely eradicated from India?

(a) small pox

(b) poliomyelitis

(c) plague

(d) kala-azar.

Answer and Explanation:

14. (a): Small pox is an acute highly communicable disease. It is caused by virus named Variola virus. Now it is eradicated from world including India. It is highly infectious disease starting with high fever, chill, backache and headache, followed by appearance of rash on the third day of illness. The rash appears first on the face, then on the rest of the body.

The rash starts as small reddish spots which change into papules. These in turn change into small vesicles containing clear fluid. Vesicles change into postules. Finally, a scab is formed and it falls off by the third week. These scabs leave deep pits or scars known as pock marks. The virus is present in the oral and nasal discharges of the patients and is ejected during the acts of coughing, sneezing, etc., and infects the healthy people.

15. Which of the following symptoms indicate red- sickness?

(a) nausea and loss of hair

(b) ulcerated skin, nausea and loss of hair

(c) red and ulcerated skin

(d) nausea and anaemia.

Answer and Explanation:

15. (b): The symptoms of red sickness are ulcerated skin, nausea and loss of hair.

16. Human immuno deficiency virus (HIV) has a protein coat and a genetic material which is

(a) double stranded RNA

(b) double stranded DNA

(c) single stranded DNA

(d) single stranded RNA.

Answer and Explanation:

16. (d): HIV is a retrovirus, which contains single stranded RNA, surrounded by protein coat (core shell) as genetic material. It causes AIDS. HIV is different in structure from other retroviruses. It is around 120 nm in diameter (120 billionths of a meter; around 60 times smaller than a red blood cell) and roughly spherical.

17. Botulism caused by Clostridium botulinum affects the

(a) lymph glands

(b) central nervous system

(c) spleen

(d) intestine.

Answer and Explanation:

17. (b): Botulism is a serious form of food poisoning from foods containing the toxin produced by the bacterium Clostridium botulinum. The toxin selectively affects the central nervous system; in fatal cases, death is often caused by heart and lung failure resulting from a malfunction of the cardiac and respiratory centres of the brain. The bacterium thrives in improperly preserved foods, typically canned raw meats. The toxin, being rather unstable to heat, is invariably destroyed in cooking.

18. Typhoid fever is caused by

(a) Shigella

(b) Escherichia

(c) Giardia

(d) Salmonella.

Answer and Explanation:

18. (d): Typhoid is caused by Salmonella typhi. The organisms of the disease are present in the stool. They may be present in urine. They can, therefore, be carried by water and contaminated food. Their spread through water can give rise to severe epidemics. The temperature goes oil rising during the first week and then gradually comes down. Rest, care about food and proper nursing are absolutely essential for some days, otherwise the disease may relapse.

19. Which is showing accurate pairing?

(a) syphilis – Treponema pallidum

(b) AIDS – Bacillus conjugalis

(c) gonorrhoea – Leishmania donovani

(d) typhoid – Mycobacterium leprae.

Answer and Explanation:

19. (a): Syphilis is caused by a spirochete (spiral bacterium) Treponema pallidum. The symptoms of syphilis occur in three stages. The first stage usually consists of a painless lesion called a chance at the organism’s site of entry.

The second stage begins as the organism enters the blood. Symptoms such as fever, a flu like illness, a skin rash, hair loss, and swollen joints may come and go over a period of several years. In the third stage permanent brain damage, heart disease, and blindness often occurs.

AIDS is a viral disease caused by Human Immuno deficiency virus. Gonorrhoea is a sexual disease and its causative organism is Neisseria gonorrhoea. Typhoid is caused by bacillus bacteria Salmonella typhae.

20. Which disease of man is similar with cattle’s, bovine spongiform encephalopathy?

(a) encephalitis

(b) Jacob-cruitzfeit disease

(c) spongiocitis of cerebrum

(d) spondylitis.

Answer and Explanation:

20. (b): The common term for Bovine spongiform encephalopathy is mad cow disease, which is a progressive neurological disorobeder of cattle. In humans it is called Creutzfeldt-Jakob disease, after the two doctors who first described the symptoms of the disease. It is caused by prions (proteinaceous infectious particles). It is characterized by rapidly progressive dementia associated with myoclonic jerks. The brains of affected individuals show a characteristic cystic degeneration.

21. Saline solution is given to patients of cholera because

(a) Na+ prevents water loss from body

(b) NaCl function as regulatory material

(c) NaCl produces energy

(d) NaCl is antibacterial.

Answer and Explanation:

21. (a): Cholera is an acute infection of the small intestine by the bacterium Vibrio cholerae, which causes severe vomiting and diarrhoea (known as ricewater stools) leading to dehydration. The disease is contracted from food or drinking water contaminated by faeces from a patient. The resulting dehydration and the imbalance in the concentration of body fluids can cause death within 24 hours.

Since, a large quantity of fluid and salts are rapidly lost through stools and vomit, therefore, the most important treatment is to replace the lost fluid and salts equally rapidly. Rapid relacement of fluid and elecrolytes is needed by oral rehydration-therapy. The electrolytes consist of Na+ ions that prevent water loss from the body.

22. Salmonella is related with

(a) typhoid

(b) polio

(c) T.B.

(d) tetanus.

Answer and Explanation:

22. (a): Typhoid is caused by Salmonella typhi. The organisms of the disease are present in the stool. They may be present in urine. They can, therefore, be carried by water and contaminated food. Their spread through water can give rise to severe epidemics. The temperature goes on rising during the first week and then gradually comes down. Rest, care about food and proper nursing are absolutely essential for some days, otherwise the disease may relapse.

Polio is caused by Enterovirus. TB is caused by Mycobacterium tuberculosis. Tetanus is caused by Clostridium tetani.

23. Which is the most infectious disease?

(a) hepatitis-B

(b) AIDS

(c) cough and cold

(d) malaria.

Answer and Explanation:

23. (a): Hepatitis B (serum hepatitis) occurs at any age and mode of transmission is through contact or blood, infection is severe, often fatal and is accompanied by loss of appetite, nausea, whitish stool (due to lack of bile) and jaundice. 0.0002% of hepatitis B infected blood contact is enough to transmit hepatitis B.

24. Interferons are synthesized in response to

(a) mycoplasma

(b) bacteria

(c) viruses

(d) fungi.

Answer and Explanation:

24. (c): Interferons are proteins that increase the resistance of a cell to attack by viruses by unmasking genes that synthesize antiviral proteins. In humans, three groups of interferons have been discovered: a-interferons from white blood cells; P-interferons from connective tissue fibroblasts; and y-interferons from lymphocytes.

25. Reason of lung cancer is

(a) coal mining

(b) calcium fluoride

(c) cement factory

(d) bauxite mining.

Answer and Explanation:

25. (a): Lung cancer is a disease where tissue in the lung grows out of control. This may lead to metastasis, invasion of adjacent tissue and infiltration beyond the lungs. The vast majority of primary lung cancers are carcinomas of the lung, resulting from epithelial cells,. One of the causes of lung cancer is exposure to coal dust. Exposure to coal dust can cause some coal mine workers to develop pneumoconiosis, or “black lung.” This occurs when inhaled coal dust becomes embedded in the lungs, causing them to harden and making breathing difficult.

26. Cancerous cells can easily be destroyed by radiations due to

(a) rapid cell division

(b) lack of nutrition

(c) fast mutation

(d) lack of oxygen.

Answer and Explanation:

26. (a): Cancerous cells are the cells that undergo rapid cell division. These cells are destroyed by X-ray radiaton. During cell division, the DNA double helix opens up and undergoes various other processes. Such processes are disrupted when exposed to radiation and the cancerous cells die selectively when radiated.

27. Which of the following is an example of sex linked disease?

(a) AIDS

(b) colour blindness

(c) syphilis

(d) gonorrhoea.

28. Carcinoma refers to

(a) malignant tumours of the connective tissue

(b) malignant tumours of the skin or mucous membrane

(c) malignant tumours of the colon

(d) benign tumours of the connective tissue

29. Christmas disease is another name for

(a) haemophilia B

(b) hepatitis B

(c) Down’s syndrome

(d) sleeping sickness

Answer and Explanation:

29. (a): Haemophilia B, a type of haemophilia is also known as Christmas disease. It is due to deficiency of a blood coagulation factor, the Christmas factor (factor IX). Christmas was the person (20th century) in whom the factor was first identified. Haemophilia B is a defect of the blood which prevents its clotting.

30. Which one of the following is not correctly matched?

(a) Glossina palpalis – Sleeping sickness

(b) Culex pipiens – Filariasis

(c) Aedes aegypti – Dengue fever

(d) Anopheles culifacies- Leishmaniasis.

Answer and Explanation:

30. (d): All the options given are diseases with their associated vector which transmit the respective diseases. Leishmaniasis, also called kala azar is caused by Leishmania donovani. It is spread by sand fly (Phlebotomus) and characterised by enlarged spleen and liver with high fever.

Sleeping sickness is caused by a protozoan Trypanosoma gambiense. Filariasis is caused by worm Wuchereria bancrofti. Dengue fever is caused by arbo virus.

31. The ‘blue baby’ syndrome results from

(a) excess of TDS (total dissolved solids)

(b) excess of chloride

(c) methaemoglobin

(d) excess of dissolved oxygen

Answer and Explanation:

31. (c): Blue baby syndrome is used to describe newborns with cyanotic conditions. It is a pathological condition in which blood’s capacity for oxygen transport is reduced, resulting in bluish skin in infants. Blue baby syndrome begins when large amounts of nitrates in water are ingested by an infant and converted to nitrite by the digestive system.

The nitrite then reacts with oxyhaemoglobin (the oxygen-carrying blood protein) to form methaemoglobin, which cannot carry oxygen. If a large enough amount of metheglobin is formed in the blood, body tissues may be deprived of oxygen, causing the infant to develop a blue coloration of their mucous membranes and possibly digestive and respiratory problems.

Methaemoglobin is a form of the oxygen-carrying protein haemoglobin, in which the iron in the haem group is in the Fe3+ state, not the Fe2+ of normal haemoglobin.

32. The causative agent of mad-cow disease is a

(a) virus

(b) bacterium

(c) prion

(d) worm

Answer and Explanation:

32. (c): Mad cow disease is the common term for Bovine spongiform encepholopathy (BSE), a progressive neurological disorder of cattle. It is caused by prions. Symptoms include an excitable or nervous temperament to external stimuli such as touch to the skin.

A prion (short for proteinaceous infectious particle) is a unique type of infectious agent, as it is made only of protein. Prions are abnormally-structured forms of a host protein, which are able to convert normal molecules of the protein into the abnormal structure.

33. The bacterium (Clostridium botulinum) that causes botulism is

(a) an obligate aerobe

(b) a facultative anaerobe

(c) an obligate anaerobe

(d) a facultative aerobe

Answer and Explanation:

33. (c): Clostridium is a genus of gram-positive bacteria. They are obligate anaerobes capable of producing endospores. Individual cells are rod-shaped. Foodborne disease caused by C. botulinum is referred to as botulism (a muscle-paralyzing disease). It is caused by the ingestion of a neurotoxin (botulin) prod.uced by the microorganism in the food.

Botulin blocks nerve function leading to respiratory and musculoskeletal paralysis. Symptoms of botulism include weakness, fatigue and dizziness, followed by blurred vision and progressive difficulty in speaking and swallowing. Weakening of the respiratory muscles is also observed and death may occur due to respiratory failure.

34. HIV that causes AIDS first starts destroying

(a) helper T-lymphocytes

(b) p-lymphocytes

(c) leucocytes

(d) thrombocytes

Answer and Explanation:

34. (a): AIDS, is a sexually transmitted disease of the human immune system that is caused by infection with HIV. It is characterized by reduction in the numbers of CD4-bearing helper T cells to 20 percent or less of normal.

35. Increased asthmatics attacks in certain seasons are related to

(a) eating fruits preserved in tin containers

(b) inhalation of seasonal pollen

(c) low temperature

(d) hot and humid environment.

Answer and Explanation:

35. (b): Increased asthmatic attacks in certain seasons are related to inhalation of seasonal pollen. Pollens are microscopic grains produced by plants in order to reproduce. Pollen allergy is a hypersensitive reaction to pollen. Pollen induced reactions include extrinsic asthma, rhinitis and bronchitis.

Asthma can be defined clinically as a condition of intermittent, reversible airway constriction, due to a hyper­reactivity to certain substances producing inflammation. In an asthma attack the smooth muscles of the lungs go into spasm with the surrounding tissue inflammed and secreting mucus into the airways. Thus, the diameter of the airways is reduced causing the characteristic wheezing as the person affected breathes harder to get air into the lungs.

Attacks can vary in intensity and frequency. An asthmatic attack may be triggered by environmental allergens, such as pollen, animal dander, mold spores, house dust, feather pillows, some foods, or any other sensitive substance. Asthmatic attacks may also result from infections, emotional stress, fatigue, endocrine changes and temperature and humidity changes. Cigarette smoking is a major factor in asthma.