Biology MCQs

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Antidiuretic Hormone (ADH) controls the amount of water absorption by the nephrons. It is also called arginine vasopressin.

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Glycolysis, part of cellular respiration, is a series of reactions that constitute the first phase of most carbohydrate catabolism, catabolism meaning the breaking down of larger molecules into smaller ones. Glycolysis breaks down glucose and forms pyruvate with the production of two molecules of ATP. The entire process from conversion of glucose to pyruvate is anaerobic that is it does not take place in presence of oxygen.

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Anaerobic reactions involve break down of glucose into pyruvic acid, which then reacts to produce lactic acid. As muscle metabolism shifts from aerobic to anaerobic ATP production, lactic acid begins to accumulate in muscles and to appear in the bloodstream. This leads to muscle fatigue with changing pH of muscle cells. C6H12O6 —> 2C3H6O3 + 2ATP

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Hydra is radially symmetrical, that is, the parts of its body are arranged in a circle around a central median axis passing through the mouth. Hydra reproduces by asexual and sexual methods. Asexual reproduction takes place either by budding or by fission.

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Evolutionary biologists classify tailbone as vestigial organs, or body parts that have become functionless due to evolution. It is perhaps the most commonly touted example in man of a “useless” evolutionary vestige. Also known as coccyx (because of its similarity to the shape of a cuckoo’s beak), tailbone is a vestigial tail left over from our tailed monkey- like ancestors.

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Food is any substance that is consumed by human beings to obtain energy and nutritional support. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingested and assimilated by the cells to provide energy, maintain life, or stimulate growth.

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During the process of photosynthesis, light penetrates the cell and passes into the chloroplast. The light energy is intercepted by chlorophyll molecules on the granal stacks. Some of the light energy is converted to chemical energy. During this process, a phosphate is added to a molecule to cause the formation of ATP.

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Ringworm, also known as dermatophytosis or tinea, is a fungal infection of the skin or scalp. The name “ringworm” is a misnomer, since the infection is caused by a fungus, not a worm. The infection initially presents with red patches on affected areas of the skin and later spreads to other parts of the body.

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Vitamin K is a group of structurally similar, fat-soluble vitamins that are needed for the post translational modification of certain proteins required for blood coagulation i.e. conversion of fibrinogen into fibrin, the blood clot. and in metabolic pathways in bone and other tissue. They are 2-methyl-1,4- naphthoquinone (3-)derivatives. This group of vitamins includes two natural vitamins: vitamin K1 and vitamin K2. Vitamin K1, also known as phylloquinone, phytomenadione, or phytonadione, is synthesized by plants, and is found in highest amounts in green leafy vegetables because it is directly involved in photosynthesis. It may be thought of as the “plant form” of vitamin K. It is active in animals since animals can easily convert it to vitamin K2.

Notes:
More than one option is correct. Jatropha curcas is known for its insecticidal, pesticidal and fungicidal properties. It is used in rural Bengal for dhobi itch (a common fungal infection of the skin). Pesticidal properties have also been reported from Pongamia Pinnata (Karanja) especially against nematodes.