Biology GK Questions Quiz-50

Biology GK Questions Quiz-50

Biology Multiple Choice Questions (MCQs) Quiz for State and UPSC Civil Services Examinations. Objective Questions on Biology for competitive examinations.

    981. Thiamidine dimer formation in DNA is caused by

    (1) IR-rays 
    (2) X-rays
    (3) b and g-rays 
    (4) UV-rays
    Answer:
    981. (4) When cells are exposed to sunlight, radiant energy can damage the DNA. For example, ultraviolet irradiation causes covalent bond formation between adjacent thymines on the same strand of DNA. Ultraviolet light is absorbed by a double bond in thymine and cytosine bases in DNA. This added
    energy opens up the bond and allows it to react with a neighboring base.

    982. Which one of the following statements about PYROLYSIS, which is a process for solid waste treatment is incorrect?

    (1) It converts the waste into solid, liquid and gas of which the resultant liquid and gas can be used to produce energy.
    (2) The process occurs at a temperature above 430°C at atmospheric pressure.
    (3) The process occurs under high pressure at temperature above 430° C.
    (4) It is a thermochemical decomposition of organic waste
    Answer:
    982. (2) Pyrolysis is a thermo-chemical decomposition of organic material at elevated temperatures in the absence of oxygen (or any halogen). Pyrolysis generally takes place well above atmospheric pressure at temperatures exceeding above 430 °C.

    983. Haptens are:

    (1) Pseudoantigens
    (2) Incomplete antigens
    (3) Antibodies
    (4) Isoantigens
    Answer:
    983. (2) Haptens are small molecules that react with a specific antibody but cannot induce the formation of antibodies unless bound to a carrier protein or other large antigenic molecule. They are incomplete or
    partial antigens.

    984. Wilting of plants occurs due to excessive :

    (1) Respiration 
    (2) Guttation
    (3) Absorption
    (4) Transpiration
    Answer:
    984. (4) Plant wilting occurs after excessive loss of water by transpiration and lesser absorption. On a hot day, plants transpire heavily and cannot absorb water speedily to keep pace with transpiration loss, even when there is enough water.

    985. Wings of birds are:

    (1) Modified hind limbs
    (2) New structure
    (3) Integumentary outgrowth
    (4) Modified fore limbs
    Answer:
    985. (4) The wings are modified forelimbs of birds which are the key to bird flight. Each wing composed of three limb bones, the humerus, ulna and radius.

    986. The casual organism of Polio is :

    (1) A fungi 
    (2) A virus
    (3) A worm 
    (4) A bacteria
    Answer:
    986. (2) Polio is a highly infectious disease caused by a virus. Its causative agent, poliovirus, was identified in 1908 by Karl Landsteiner. The polio virus invades the nervous system, and can cause total paralysis in a matter of hours.

    987. Panda belongs to the same family as that

    (1) Kangaroo 
    (2) Porcupine
    (3) Whale 
    (4) Bear
    Answer:
    987. (4) It is generally considered that the Panda belongs to the bear family, though differences persist. Some DNA studies have shown that the giant panda is closer to the bear family while the red panda is indeed closer to the raccoon family.

    988. A cellulosic wall is found in the cells of

    (1) animals 
    (2) bacteria
    (3) fungi 
    (4) plants
    Answer:
    988. (4) Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. It is a complex carbohydrate, (C6H10O5)n, that is composed of glucose units.

    989. The filtration unit of kidney is

    (1) axon 
    (2) nephron
    (3) neuron 
    (4) yellow fiber
    Answer:
    989. (2) 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.

    990. The nutritive tissue in the seeds of higher plants is known as

    (1) hypocotyl 
    (2) embryo
    (3) endosperm 
    (4) nucellus
    Answer:
    990. (3) The seed includes three primary regions: the embryo, nutritive tissue, and seed coat. Endosperm is a nutritive tissue that sustains the embryo and seedling. The endosperm may be consumed by the embryo, as in many legumes, which use the cotyledons as a food source during germination.

    991. Yeast is an important source of

    (1) vitamin B 
    (2) invertase
    (3) vitamin C 
    (4) protein
    Answer:
    991. (1) Yeast is an important source of most B vitamins (except B12) and folate and contains potassium and magnesium. It is used in the preparation of vitamin B complex tablets.

    992. Match correctly the infectious agents given in List I with the diseases caused by them given in List II :

    List-I
    a. Bacterium 
    b. Fungus
    c. Protozoan 
    d. Virus
    List-II
    1. Kala-azar 
    2. Tuberculosis
    3. Influenza 
    4. Ringworm
    (1) a-1, b-2, c-4, d-3
    (2) a-2, b-4, c-1, d-3
    (3) a-3, b-1, c-2, d-4
    (4) a-4, b-2, c-3, d-1
    Answer:
    992. (2) Kala-azar: caused by protozoan parasites; Tuberculosis: infectious disease caused by various strains of myco-bacteria; Influenza: caused by RNA viruses; and Ringworm: fungal infection of the skin.

    993. Enzymes are

    (1) Steroids
    (2) Carbohydrates
    (3) Proteins
    (4) Lipids
    Answer:
    993. (3) Enzymes are proteins that speed up chemical reactions in the cell. They are highly selective
    catalysts, greatly accelerating both the rate and specificity of metabolic reactions. Most enzymes are
    proteins, although some catalytic RNA molecules have been identified.

    994. The plant that behaves as a root parasite is

    (1) Ficus 
    (2) Santalum
    (3) Cuscuta 
    (4) Euphorbia
    Answer:
    994. (3) Plants which either obtain readymade organic food prepared by other plants or absorb water and minerals from other plants to prepare their own organic food are called parasitic plants. Cuscuta
    (Doddar) is a total stem parasite.

    995. The largest White Blood Corpuscle is

    (1) Lymphocyte 
    (2) Monocyte
    (3) Thrombocyte 
    (4) Erythrocyte
    Answer:
    995. (2) Monocytes are the largest white blood cell. When they leave the blood they’re called macrophages. Macrophages work with lymphocytes as antigen presenting cells.

    996. Which of the following does not act both as an exocrine gland and as an endocrine gland ?

    (1) Pituitary 
    (2) Pancreas
    (3) Testis 
    (4) Ovary
    Answer:
    996. (1) The pancreas, located in the abdomen close to the stomach, is both an exocrine and an endocrine gland. Similarly, gonads (both ovaries and testes) are examples of organs that have both endocrine and exocrine functions. The endocrine function of the gonads is the production of the sex hormones (estrogens and androgens); while their exocrine function is to produce gametes.

    997. Match correctly the Nutrient defficiency given in List-I with the diseases caused by the deficiency given in List-II. 

    List -I 
    (a) Iodine 
    (b) Iron 
    (c) Niacin 
    (d) Vitamin Bl2 
    List - II
    (i) Microcytic anaemia
    (ii) Pernicious anaemia
    (iii) Goitre
    (iv) Pellagia
    (a) (b) (c) (d)
    (1) (iv) (ii) (i) (iii)
    (2) (i) (iii) (ii) (iv)
    (3) (ii) (iv) (iii) (i)
    (4) (iii) (i) (iv) (ii)
    Answer:
    997. (4) Microcytic anaemia: anemia characterized by small red blood cells, due to deficiency of iron; Pernicious anaemia: body does not make enough red blood cells due to lack of vitamin B12; Goitre: swelling of the neck or larynx resulting from iodine deficiency; and Pellagra: chronic lack of niacin (vitamin B3).

    998. Name the tiny pores present on the surface of leaves in plants.

    (1) Pits 
    (2) Stomata
    (3) Trichomes 
    (4) Hydathodes
    Answer:
    998. (2) Stomata are pores in the surface of the leaf. The pore is surrounded by two guard cells. When these two guard cells take up water, they bend and open up the pore between them.

    999. Rinderpest disease of Cattle is caused by

    (1) Insects 
    (2) Bacteria
    (3) Virus 
    (4) Protozoa
    Answer:
    999. (3) Rinderpest is an acute, highly contagious viral disease of ruminant animals, primarily cattle, that was once common in Africa, the Indian subcontinent, and the Middle East.

    1000. Which of the following series is true about energy flow in an ecosystem ?

    (1) Producers ® Decomposers ® Consumers
    (2) Decomposers® Consumers ® Producers
    (3) Producers ® Consumers ® Decomposers.
    (4) Consumers ® Producers ® Decomposers.
    Answer:
    1000.(3) Producers ® Consumers ® Decomposers.

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