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Part 099 – Biology Previous Year Questions

Q1. The red colour of human blood is due to
(a) myoglobin
(b) hemoglobin
(c) immunoglobulin
(d) haptoglobin
Ans: (b) Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates which carries oxygen from the respiratory organs to the rest of the body. It changes shape when it binds oxygen. When it changes shape, it absorbs different wavelengths of light, making it change color. When blood is exposed to air, much more of the hemoglobin absorbs oxygen than had in the vein the blood came from. Therefore, the blood turns red.

Q2. The functional unit of the kidney is

(a) neuron (b) glomerulus
(c) nephron (d) ureter
Ans: (c) Nephron is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine. A nephron eliminates wastes from the body, regulates blood volume and blood pressure, controls levels of electrolytes and metabolites, and regulates blood pH.

Q3. Which of the following is called the powerhouse’ of the cell ?

(a) Nucleus
(b) Lysosome
(c) Chromosome
(d) Mitochondrion
Ans: (d) Mitochondria are sometimes described as “cellular power plants” because they generate most of the cell’s supply of adenosine tri-phosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in other tasks such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth.

Q4. Acquired Immuno-Deficiency Syndrome (AIDS) is caused by

(a) protozoa (b) virus
(c) fungus (d) bacteria
Ans: (b) Human immunodeficiency virus infection / acquired immunodeficiency syndrome (HIV/AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV).

Q5. Which of the following processes does not increase the amount of carbon dioxide in air ?

(a) Breathing
(b) Photosynthesis
(c) Burning of petrol
(d) Aerobic decay of vegetation
Ans: (b) Plants reduce the CO2, because they use it with photosynthesis. They use it to give oxygen and carbohydrates as the final product. It is for this reason that plantation of trees has been stressed by environmentalists.

Q6. The vitamin that is most readily manufactured in our bodies is

(a) vitamin A (b) vitamin B
(c) vitamin C (d) vitamin D
Ans: (d) Vitamin D is not really a vitamin, but a precursor for the most potent steroid hormone in the human body. It can be obtained from exposure to the sun’s ultraviolet (UV) radiation, especially during the early morning hours.

Q7. Which cells in our body have the least regenerative power?

(a) Brain cells (b) Muscle cells
(c) Bone cells (d) Liver cells
Ans: (a) Brain cells do not regenerate. Once lost, they do not come back. Research from Karolinska Institute in Sweden haves shown that the nerve cells of the brain remain the same throughout a person’s life.

Q8. A potato tuber has been cut into two halves. A few drops of iodine solution are placed on the cut surface of one of the halves. What colour change will be noticed?

(a) From brown to blue–black
(b) From brown to orange–red
(c) From blue to pink
(d) From pink to blue–green
Ans: (a) Any form of starch (carbohydrate) turns blue-black when iodine solution is applied to it. This is because starch is composed of polymers of glucose. Long linear chains are amylose. Amylopectin is similar but contains a branch point about every 25th glucose or so. Amylose coils into a helical secondary structure resembling a tube with a hollow core. Certain molecules including fatty acids and iodine can lodge inside the core as already mentioned. The complex of iodine stuck inside the amylose coil produces a characteristic blue-black colour.

Q9. How many valves does a human heart have?

(a) Four (b) Three
(c) Two (d) One
Ans: (a) Human heart has four valves: two atrioventricular (AV) valves, which are between the atria and the ventricles, are the mitral valve and the tricuspid valve; and two semilunar (SL) valves, which are in the arteries leaving the heart, are the aortic valve and the pulmonary valve. A heart valve normally allows blood flow in only one direction through the heart.

Q10. The cells which are responsible for the production of antibodies are

(a) red blood cells
(b) neutrophils
(c) lymphocytes
(d) platelets
Ans: (c) An antibody (Ab), also known as an immunoglobulin (Ig), is a large Y-shaped protein produced by B-cells that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. Each antibody is produced by lymphocytes (specialized white cells) as a result of exposure to specific chemical substances called antigens usually on the outside of an invading organism. This is called the antigen-antibody reaction.

Q11. The source of the enzyme, diastase is

(a) salivary gland
(b) stomach
(c) liver
(d) pancreas
Ans: (a) Diastase was the very first enzyme discovered. This enzyme helps break down carbohydrates and turn them into sugar, which makes them easier to digest. It is found ins uch sources as milk, saliva and other plants.

Q12. Mycoplasma is associated with a disease that affects the organs of

(a) respiration
(b) excretion
(c) reproduction
(d) digestion
Ans: (a) Mycoplasma refers to a genus of bacteria that lack a cell wall. Several species are pathogenic in humans, including M. pneumoniae, which is an important cause of pneumonia (an inflammatory condition of the lung—affecting primarily the microscopic air sacs known as alveoli) and other respiratory disorders, and M. genitalium, which is believed to be involved in pelvic inflammatory diseases.

Q13. Which one of the following pairs is correctly matched?

(a) Tetanus – BCG
(b) Tuberculosis – ATS
(c) Malaria – Chloroquin
(d) Scurvy – Thiamin
Ans: (c) Chloroquine prevents the development of malaria parasites in the blood. Doctors use it to both prevent and treat malaria.

Q14. A person having AB-group of blood can donate blood to a person having

(a) A-group (b) B-group
(c) AB-group (d) O-group
Ans: (c) If a person belongs to the blood group AB, he has both A and B antigens on the surface of his red blood cells and no A or B antibodies at all in his blood plasma. So he can donate blood to those having AB blood group; but can receive blood from AB, A, B, and O groups.

Q15. Which of the following is known as the graveyard of RBC ?

(a) Liver (b) Spleen
(c) Brain (d) Heart
Ans: (b) Red Blood Cells (RBC) take their origin in the bone marrow. The liver also produces RBC, but only during infancy. The average life span of RBC is about 100- 120 days. The old, worn out and dead RBC are destroyed mainly in an organ called spleen. Hence, bone marrow is commonly called the cradle of RBC’ and spleen is commonly called the ‘graveyard of RBC’.

Q16. The largest mixed gland of human body is :

(a) Thymus (b) Liver
(c) Pancreas (d) Spleen
Ans: (c) Pancreas is a mixed gland having both endocrine and exocrine functions. The exocrine portion secretes digestive enzymes into the duodenum via the pancreatic duct. The endocrine portion secretes two hormones, insulin and glucagon, into the blood.

Q17. Mumps is a viral disease that c inflammation of :

(a) Parotid gland
(b) Sublingual gland
(c) Submaxillary gland
(d) Infra-orbital gland
Ans: (a) The parotid gland is a salivary gland in humans. It is one of a pair, and the largest of the salivary glands. Inflammation of one or both parotid glands is known as parotitis. The most common cause of parotitis is mumps.

Q18. Match the following :
List – I List – II

(a) Aquaculture (a) Silk
(b) Floriculture (b) Grapes
(c) Sericulture (c) Flower
(d) Viticulture (d) Fisheries
(a) (b) (c) (d)
(a) 4 3 2 1
(b) 3 4 1 2
(c) 3 4 2 1
(d) 4 3 1 2
Ans: (d) Aquaculture: farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants; Floriculture: cultivation of flowering and ornamental plants for gardens and for floristry; Sericulture: rearing of silkworms for the production of raw silk; and Viticulture: production and study of grapes.

Q19. Rheumatic heart disease is treated with the help of:

(a) Aspirin
(b) Streptomycin
(c) Methyl dopa
(d) Penicillin
Ans: (a) Rheumatic heart disease is heart valve damage that occurs after an episode of rheumatic fever. To reduce inflammation, aspirin, steroids, or nonsteroidal medications may be given. Aspirin in antiinflammatory doses effectively reduces all manifestations of the disease except chorea, and the response is typically dramatic.

Q20. Which of the following relieves pain ?

(a) Antibiotics (b) Analgesic
(c) Antipyretic (d) Disinfectant
Ans: (b) An analgesic is any member of the group of drugs used to achieve analgesia, relief from pain. Commonly known as painkillers, analgesic drugs act in various ways on the peripheral and central nervous systems.

Q21. Tobacco smoke is injurious to health because it contains :

(a) Carbon monoxide
(b) Nicotine
(c) Polycyclic aromatic hydrocarbons
(d) Melathene
Ans: (a) Tobacco smoke contains carbon monoxide which is a poisonous gas. It interferes with uptake of oxygen in the lungs and with its release from the blood to the tissues that need it. When carbon monoxide is inhaled it combines with haemoglobin in the blood to form carboxyhaemoglobin, which reduces the amount of oxygen available to the body’s vital organs. Oxygen levels may be reduced by as much as 15%.

Q22. Enzymes are :

(a) Micro organisms
(b) Proteins
(c) Inorganic compounds
(d) Moulds
Ans: (b) Enzymes are proteins that act as a catalyst, lowering the activation energy of a reaction, therefore dramatically increasing the rate of the reaction. Like all proteins, enzymes are long, linear chains of amino acids that fold to produce a three-dimensional product which determines their specific activities.

Q23. Which one of the following is not a benefit of saliva ?

(a) It facilitates swallowing
(b) It increases RBCs in the body
(c) It keeps the mouth and teeth clean
(d) It aids speech by facilitating movements of lips and tongue
Ans: (b) Saliva does not increase the number of red blood cells in the body which is a condition of disease called Polycythemia. It results in an increased level of circulating red blood cells in the bloodstream.

Q24. Fiber diet includes :

(a) glycogen (b) proteins
(c) cellulose (d) fats
Ans: (c) The components of dietary fiber include cellulose, lignin (only non-carbohydrate component of dietary fiber), pectin, chitan, etc. Such fibers increase fecal bulk and speed up the passage of food through the digestive tract.

Q25. Tuberculosis infection is by means of :

(a) Mycobacterium avonin
(b) Staphylococcus
(c) Mycobacterium tuberculosis
(d) Streptococcus
Ans: (c) Tuberculosis is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis typically attacks the lungs, but can also affect other parts of the body. It is spread through the air.

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