Biology MCQs

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Centrosome is an organelle that serves as the main microtubule organizing centre (MTOC). Basal granules are cellular organelles that are similar to the centriole in structure and are found at the base of a cilium or flagellum.

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The Great Zebra, Lesser Zebra and Spotted Zebra are the swallowtail butterfly found in the Southeast Asia, which are relatively common and not threatened species.

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Photosynthesis can take place in leaves, stem or green part of plant which containing chlorophyll.

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Amniocentesis is a medical procedure used primarily in prenatal diagnosis of chromosomal abnormalities and foetal infections, as well as for sex determination.

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Under suitable conditions, a single cell grows into a colony of cells on agar medium. The resulting population of genetically identical cells derived from a single parent cell is called a clone.

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Viroids are the smallest infectious pathogens known. They are composed solely of a short strand of circular, single-stranded RNA that has no protein coating. All known viroids are inhabitants of higher plants, in which most cause diseases, ranging in economic importance.

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This question is might have trapped almost all of you. The option A which etymologically linked to the question would trap you. We should note that Abscisic acid plays any significant role in leaf abscission is unfortunately not proved. The hormone is also called Dormin and its major functions are inhibition. But abscission of leaves is something better explained by Auxin-ethylene roles. Kindly surf the web and try to find out, if I am right. Inhibition of growth and maintenance of the dormancy of buds are the most striking effects of ABA. ABA activity alone is not enough to keep the dormancy of buds up in the long term though. Further, ABA is an efficient inhibitor of germination and occurs in high concentrations in dormant seeds. The role ABA has during the abscission of fruits and leaves is largely unknown. Though both cases seem to be governed by similar mechanisms (Auxin-Ethylene to a great extent) has ABA nearly no effect on the abscission of leaves while it shows a clear effect on fruit abscission. The role of Abscisic acid in abscission was a pharmacological artifact…applied AbA often induces ethylene biosynthesis.

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The branch of science that deals with the study of the mental faculties of the brain including emotions is known as Phrenology.

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Thallophytes are commonly known as algae. Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic organisms. They are found in a wide variety of habitats such as moist rocks, soil and wood.

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Pyrenoids are the center of the formation of Starch. Pyrenoids are non-membrane-bound organelles found in the chloroplasts of algae and hornwort plants. It can be seen by light-microscopy.