Biology MCQs

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Prolactin initiates and maintains milk production in breasts. Prolactin secretes by the Pituitary gland.

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44 is the number of autosomes in a human primary sperm cell. An autosome is a chromosome, which is not a sex chromosome.

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Listeriosis is a serious infection caused by Listeria monocytogenes. It is caused by eating food contaminated with the bacterium Listeria monocytogenes.

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Zoonosis is an infectious disease that has jumped from non-human animals to humans.

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The female Anopheles mosquito distinguishes itself as both a parasite and vector host. It feeds on human blood, causing minor harm, hence proving its parasitic nature. And in its role as a vector, it allows the Plasmodium parasite, which is responsible for malaria, to mature and multiply inside its body before transmitting it to humans. Meanwhile, Ascaris lumbricoides and Fasciola hepatica act solely as parasites. House flies can serve as vectors, but are generally not classified as parasites.

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Holstein Friesian cows are world’s highest-production dairy animals and dominate the global dairy industry. These cows originated in Dutch provinces of North Holland and Friesland, and Schleswig-Holstein in Northern Germany. They are known as Holsteins in North America and Friesians in UK and Ireland.

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Nitrogen-fixing bacteria are microorganisms capable of transforming atmospheric nitrogen into fixed nitrogen. Rhizobium is one such bacteria that is associated with leguminous plants (e.g., various members of the pea family). It invades the root hairs of host plants and convert free nitrogen to ammonia, which the host plant utilizes for its development.

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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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Feed cost is one of the important variable costs that plays a big role in determining the poultry cost. Variable costs rise and fall with the size of the output and the level of the operation. Fixed costs (for items such as taxes, insurance, interest, and depreciation on buildings and equipment), are incurred whether or not there is any output. Moreover the feed of broilers and layers varies with time of their growth.

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It is during the pupa or cocoon stage that the silkworm yields the fibre of commercial use. As the silkworm prepares to pupate, it spins a protective cocoon. About the size and color of a cotton ball, the cocoon is constructed from one continuous strand of silk, perhaps 1.5 km long (nearly a mile). The silk cocoon serves as protection for the pupa.