Biology MCQs

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The technique of genetic engineering crosses the limits of conventional hybridization processes.

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There are basically two approaches to cloning the entire genome. In the first approach, systematic cloning is performed and the second approach is based on randomly cloning overlapping fragments.

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The petiole is the stalk-like structure which connects the leaf blade to the stem. The petiole has tiny tubes, that connect the veins on the leaf blade to the stem. Few of these enable water transport to the leaf while the other carry food away from the leaf to other parts of the plant.

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Mitochondria is an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. It is for this reason that mitochondria are often referred to as the powerhouses of the cell mitochondria also play a key role in the ageing process as well as in the onset of degenerative disease.

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Glycogen, the principal storage form of glucose in animal cells, sometimes called “animal starch” for its resemblance with starch found in plants. It is stored in liver and muscle cells and can be converted to glucose if needed. In the liver this conversion is regulated by the hormone glucagon.

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Robert Hooke (1665) observed a section of cork under his microscope and found its structure resembling a ‘honey comb’. He gave the name ‘cell’ to each of the compartments of the honey comb like structure. Two German biologists, M Schleiden and T Schwann, later proposed the famous cell theory in 1938-39.

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The best-known and most common chromosome abnormality in humans is Down’s syndrome, (Trisomy of 21st pair of chromosome). Down’s syndrome individuals also almost invariably develop Alzheimer’s disease, a form of dementia that is fairly common among the elderly people. People with Down’s syndrome develop this disease in their fourth or fifth decade of life, much sooner than other people. These people are also characterized by presence of webbed neck, Plamers crease, very broad forehead, round face and forked tongue.

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A carnivore is an organism that mostly eats meat, or the flesh of animals. Carnivores that eat herbivores are called secondary consumers, and large carnivores that eat other carnivores are called tertiary consumers. Animals and people who eat both animals and plants are called omnivores. Sometimes carnivores are also called predators.

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Vitamins are classified as either fat soluble (vitamins A, D, E and K) or water soluble (vitamins B and C).The fat soluble vitamins are soluble in lipids (fats); water-soluble vitamins are those that dissolve in water upon entering the body. Because of this, our body cannot store excess amounts of water-soluble vitamins for later use.

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A tendon is a fibrous connective tissue which attaches muscle to bone. A ligament is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable.