Biology MCQs

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The prostate gland is an accessory reproductive gland in male mammals. It is located just below the bladder in men.

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Klinefelter’s syndrome is an example of Chromosomal Disorder in which a genetic condition that results when a boy is born with an extra copy of the X chromosome.

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The root nodules for nitrogen fixation of a non-legume tree are Frankia. It is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants.

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Fluorine is the element that is associated with teeth disorder because the presence of sodium fluoride in drinking water at the level of 2ppm may cause mottled enamel in teeth, skeletal fluorosis, and may be associated with cancer and other diseases. However, topically applied fluoride (toothpaste, dental rinses) has been shown to help reduce dental caries.

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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.

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Vitamin C is also known as ascorbic acid (C6H8O6). It is a water-soluble vitamin that occurs as a white or slightly yellow crystal or powder with a slight acidic taste. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone.

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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 diaphragm is a barrier method of birth control. It is a reusable dome-shaped cup that covers a woman’s cervix, stopping sperm from joining an egg. In order for a diaphragm to work best, it must be used with spermicide (a cream or gel that kills sperm).

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Photosynthesis is the process by which light energy is converted into chemical energy by organisms. Carbon dioxide and water are the raw materials of this process. The light energy comes from the Sun and its end products are oxygen and glucose.

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Enzymes are sometimes called biological catalysts because they speed up reactions, and only small amounts are required. Digestive enzymes speed up the breakdown of complex food substances into simpler subunits. The breakdown of food in digestion is actually caused by water chemically splitting the complex food molecules, a process called hydrolysis.