Multiple Choice Questions

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Jacob and Monod name some enzymes as allosteric whose activity is regulated by

  • End product

  • Substrate

  • by product

  • Coenzyme


A.

End product

Aliosteric modulation or feedback inhibition of enzymes is influenced by end product. It was shown by Jacob and Monod 1961 through lac operon in E.coil.


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Tyloses an outgrowth from ray or axial parenchyma cell into the lumen of a vessel, which partially or completely blocks the cavity are present in

  • Periderm

  • Heart wood

  • Sap wood

  • Secondary cortex


The following is the diagram of TS of another. Identify the parts labelled as A, B and C.

  • A-Connective, B-Endothecium, C-Pollen grain

  • A-Endothecium, B-Connective, C-Pollen grain

  • A-Pollen grain, B-Connective, C-Endothecium

  • A-Endothecium, B-Pollen grain, C-Connective


Zero growth means

  • Natality balance mortality

  • Natality is more than mortality

  • Natality is less than mortality

  • Natality is zero


The net requirement of assimilatory power for the formation of 6 hexose molecules in maize plant is

  • 72 ATP, 48 NADPH

  • 90 ATP, 60 NADPH

  • 108 ATP, 72 NADPH

  • 180 ATP, 72 NADPH


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Rauwolffia serpentina is used in

  • Curing high blood pressure

  • Kidney failure

  • Eye defect

  • Diabetes


 ‘Sun basket’ is

  • The device to utilize sun rays directly to meet the requirement of heat energy

  • The sufficient amount of sunlight stored in a cell

  • A device of taking a sunbath

  •  All of the above


The most recent and direct pre-historic ancestor is

  • Cro-magnon

  • Neanderthal

  • Pre-neaderthal

  • None of these


Ethylene is related with

  • Aerobic respiration

  • Climacteric phenomenon

  • Anaerobic respiration

  • Fermentation


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In some organisms, karyokinesis is not followed by cytokinesis as a result of which, the multinucleate condition arises leading to the formation of the syncytium. The perfect example of this is

  • The appearance of a furrow in the cell membrane

  • Liquid endosperm in coconut

  • Sexual reproduction

  • Fertilization