Biology MCQs

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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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Induced fit theory is also known as Koshland’s theory of enzyme action. It describes the enzyme-substrate interaction.

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Biomolecules are organic molecules, which are involved in the metabolic process of the living organism. The four important classes of biomolecules are carbohydrates, Proteins, Nucleic acids and Lipids.

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Mycoplasma is a genus of bacteria that do not have a cell wall surrounding the cell membrane.

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FE Fritsch (1935) in his book “Structure and Reproduction of Algae” divided algae into the following eleven classes. It is mainly based on pigmentation, reserve food and flagellar, thallus structure, mode of reproduction, and life cycle. Hence he is known as the father of algae.

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The promeristem is the oldest and the smallest meristem tissue. It originates from the embryo. The primary meristem arises from the promeristem. It is found in the root and shoots tips.

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Carbon dioxide in the air is trapped by stomata. It captures Carbon dioxide from the surface of the leaves and CO2 enters through the tiny pores present on leaves called stomata.

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An important product of the Krebs cycle is ATP. Adenosine triphosphate (ATP) is a source of energy for use and storage at the cellular level.

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The main mode of nutrition in plants is the autotrophic mode of nutrition and leaves of plants contain chlorophyll which helps them to make their own food.

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Dormancy is the stage in which a plant slows down its cellular activity and sheds its leaves.