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Part 102 – Biology Previous Year Questions

Q1. ‘Pigeon milk’ is produced by
(a) Crop
(b) Birds
(c) Mammals
(d) All of the above
Ans: (b) Crop milk is a secretion from the lining of the crop of parent birds that is regurgitated to young birds. They are found among all pigeons and doves where they are referred to as pigeon milk. Crop milk is also produced by flamingos and some penguins. Crop milk bears little resemblance to mammalian milk, being a semi-solid substance somewhat like pale yellow cottage cheese.

Q2. In which one of the following is swim bladder absent ?

(a) Cuttlefish
(b) Bony fish
(c) Cartilaginous fish
(d) Silverfish
Ans: (c) The swim bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming. The cartilaginous fish (e.g. sharks and rays) split from the other fishes about 420 million years ago and lack both lungs and swim bladders, suggesting that these structures evolved after that split.

Q3. Which one of the following is the smallest endocrine gland in human body ?

(a) Adrenal (b) Thyroid
(c) Pituitary (d) Pancreas
Ans: (c) Pituitary gland, called Master Gland, is the smallest endocrine gland. It controls the general growth of the body and stimulates the primary sex hormones, i.e. ovaries and testes.

Q4. Yellow spots on citrus leaves is due to the deficiency of:

(a) Zinc (b) Magnesium
(c) Boron (d) Iron
Ans: (b) The deficiency of magnesium leads to yellowish green blotch near the base of the leaf between the midrib and the outer edge. The yellow area enlarges until the only green remaining is at the tip and base of the leaf as an inverted V-shaped area on the midrib.

Q5. Vector of Kala-azar is :

(a) Anopheles mosquito
(b) Culex mosquito
(c) Tse-Tsefly
(d) Sand fly
Ans: (d) Leishmaniasis (Kala azar) is a disease spread by the bite of the female sandfly. This disease is the second-largest parasitic killer in the world (after malaria). The parasite migrates to the internal organs such as liver, spleen (hence ‘visceral’), and bone marrow, and, if left untreated, will almost always result in the death of the host.

Q6. The chief raw material used for manufacturing Rayon is :

(a) Nylon
(b) Cellulose
(c) Silicon
(d) Radium and Argon
Ans: (b) Rayon is a manufactured regenerated cellulose fiber. Because it is produced from naturally occurring polymers, it is neither a truly synthetic fiber nor a natural fiber; it is a semi-synthetic or artificial fiber.

Q7. Cadmium pollution is associated with :

(a) Minamata disease
(b) Black foot disease
(c) Dyslexia
(d) Itai-itai
Ans: (d) Itai-itai disease was the documented case of mass cadmium poisoning in Toyama Prefecture, Japan, starting around 1912. The cadmium poisoning caused softening of the bones and kidney failure. The disease is named for the severe pains caused in the joints and spine.

Q8. The example of hermaphrodite animal in which cross fertilisation occurs is

(a) Hydra (b) Ascaris
(c) Earthworm (d) Silkworm
Ans: (a) Cross fertilization occurs in Hydra. The spermatozoa released from the testis of one Hydra swim about in water with their tails and finally come into contact with the ovum of another Hydra. Only one spermatozoon penetrates the ovum and fertilizes it. This results in the formation of a zygote which is diploid.

Q9. Blubber is

(a) a milky secretion of rubber plant
(b) a layer of thick fat
(c) a device to trap insects by some aquatic
(d) fungal infection of rice plants
Ans: (b) Blubber is a thick layer of vascularized adipose tissue found under the skin. Lipid-rich, collagen fiberlaced blubber comprises the hypodermis and covers the whole body, except for parts of the appendages, strongly attached to the musculature and skeleton by highly organized, fan-shaped networks of tendons and ligaments. It can comprise up to 50% of the body mass of some marine mammals during some points in their lives.

Q10. The coding segment of DNA is called in

(a) Codon (b) Muton
(c) Intron (d) Exon
Ans: (a) The genetic code by which DNA stores the genetic information consists of “codons” of three nucleotides. The functional segments of DNA which code for the transfer of genetic information are called genes. A codon is defined by the initial nucleotide from which translation starts.

Q11. Fat soluble vitamins are

(a) Tocopherol, Niacin, Cyanocobalamin
(b) Calciferol, Carotene, Tocopherol
(c) Ascorbic acid, Calciferol, Riboflavin
(d) Thiamine, Carotene, Biotin
Ans: (b) Calciferol (Vitamin D); Tocopherols and tocotrienols (Vitamin E); Phylloquinone, menaquinones (Vitamin K); and Retinol, retinal, and four carotenoids including beta carotene (Vitamin A) are all fat soluble vitamins.

Q12. Silk is produced by

(a) Egg of a silkworm
(b) Pupa of silkworm
(c) Larva of silkworm
(d) Insect itself
Ans: (c) Silk is a natural protein fibre, some forms of which can be woven into textiles. The protein fibre of silk is composed mainly of fibroin and produced by certain insect larvae to form cocoons. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori.

Q13. Which of the following is an egg laying mammal ?

(a) Bat
(b) Leafy ant-eater
(c) Whale
(d) Spiny ant-eater
Ans: (d) Monotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals. The only surviving examples of monotremes are all indigenous to Australia and New Guinea, although there is evidence that they were once more widespread. Among living mammals they include the platypus and four species of echidnas (or spiny anteaters).

Q14. The colour change in the Chameleon is due to the presence of

(a) Haemoglobin
(b) Chromatophore
(c) Chlorophyll
(d) Pneumatophore
Ans: (b) Chameleons have specialized cells, chromatophores, which contain pigments in their cytoplasm, in three layers below their transparent outer skin. Dispersion of the pigment granules in the chromatophores sets the intensity of each color. When the pigment is equally distributed in a chromatophore, the whole cell is intensively colored. When the pigment is located only in the centre of the cell, the cell appears mainly transparent.

Q15. The deficiency of iodine leads to

(a) Hyperthyroidism
(b) Goitre (c) Midgut
(d) Diabetes
Ans: (b) A goitre or goiter is a swelling of the thyroid gland which can lead to a swelling of the neck or larynx (voice box). Goitre is a term that refers to an enlargement of the thyroid and can be associated with a thyroid gland that is functioning properly or not. Worldwide, over 90% cases of goitre are caused by iodine deficiency.

Q16. Two richest known sources of edible protein are

(a) Meat and eggs
(b) Some algae and other microorganisms
(c) Soyabean and groundnut
(d) Milk and leafy vegetables
Ans: (a) Meat, fish and eggs are the richest sources of protein. An ounce of meat or fish has approximately 7 grams of protein. A large egg contains 6 grams protein.

Q17. The saliva helps in the digestion of

(a) Proteins (b) Starch
(c) Fibres (d) Fats
Ans: (b) Amylase enzymes secreted in saliva help break down starches into simpler sugar molecules that can be absorbed into the bloodstream. In this way, amylase activity influences blood glucose levels, which need to be maintained within an optimal range for good health.

Q18. Which of the following correctly explains the phenomenon of “Test Tube Baby” ?

(a) When every process of embryo formation is in the test tube.
(b) When the embryo develops in a test tube.
(c) When the fertilisation is external and development is internal.
(d) When the fertilisation is internal and development is external.
Ans: (c) Test tube baby is born from in vitro fertilization. In vitro fertilization (IVF) is a process by which an egg is fertilized by sperm outside the body: in vitro. When a woman’s natural cycle is monitored to collect a naturally selected ovum (egg) for fertilization, it is known as natural cycle IVF. The fertilized egg (zygote) is then transferred to the patient’s uterus with the intention of establishing a successful pregnancy.

Q19. Heart attack occurs due to

(a) Bacterial attack on the heart
(b) Stopping of heart beat
(c) Lack of supply of blood to the heart itself
(d) Impairment of heart’s working due to unknown reasons
Ans: (c) A heart attack occurs when blood flow to a part of your heart is blocked for a long enough time that part of the heart muscle is damaged or dies. The medical term for this is myocardial infarction. Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. If the blood flow is blocked, the heart is starved of oxygen and heart cells die.

Q20. Biodegradable wastes can usually be converted into useful substances with the help of

(a) Bacteria
(b) Nuclear proteins
(c) Radioactive substances
(d) Viruses
Ans: (a) Bacteria are the most abundant organisms which play important role in the decomposition of organic matter. Majority of bacteria involved in decomposition of organic matter are heterotrophs and autotrophs are least in proportion which are not directly involved in organic matter decomposition.

Q21. Greater population can be supported on the earth only if we eat more

(a)mutton (b) eggs
(c)plant products
(d) beef
Ans: (c) One way of analyzing carrying capacity of the earth is to calculate its net primary productivity (NPP). This is the total amount of solar energy converted into biochemical energy through plant photosynthesis, minus the energy needed by those plants for their own life processes. It represents the total food resource on earth. In the food chain, meat products stay at the top. Even at the current levels where deforestation and other forms of destruction of vegetation has been rampant, plant products can sustain an extended population base.

Q22. Which one of the following animals is sanguinivorous ?

(a) Fruit-fly (b) Mosquito
(c) House-fly (d) Snail
Ans: (b) The literal meaning of ‘sanguinivorous’ is someone subsisting on a diet of blood. Mosquitoes belong to this category.

Q23. Functional unit of ‘Kidney’

(a) Axon (b) Neuron
(c) Nephron (d) Artery
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.

Q24. Fat present below the skin surface in our body acts as a barrier against

(a) loss of heat from the body
(b) loss of essential body fluids
(c) loss of salt from the body
(d) entry of harmful micro-organisms from the environment
Ans: (a) A layer of body fat acts as an insulator and traps heat. The subcutis is the deepest layer of skin. The subcutis, consisting of a network of collagen and fat cells, helps conserve the body’s heat and protects the body from injury by acting as a “shock absorber.

Q25. The life span of RBC of man is

(a) 120 days (b) 150 days
(c) 180 days (d) 190 days
Ans: (b) 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.

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