Multiple Choice Questions

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The plant undergoes wilting when

  • xylem is blocked

  • cambium is blocked

  • phloem is blocked

  • some roots are reduced in number


A.

xylem is blocked

Wilting The condition that arises in plants when more water is lost by evaporation than is absorbed from the soil. This causes the cells to lose their turgor and the plant structure droops. Plants can normally recover from wilting if water is added to the soil, but permanent wilting and possible death can result if the plant does not have access to water for a long period of time. In certain plants wilting is important as a mechanism to avoid overheating: when the leaves droop they are taken out of direct contact with the sun's rays. When the sun sets the plant can begin to transpire at the normal rate and the cells of the leaves regain their turgor.

Xylem is responsible for transport of water. If xylem is blocked, plant will undergo wilting


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Assertion: In angiosperms the conduction of water is more efficient because their xylem has vessels.

Reason: Conduction of water by vessel elements is an active process with energy supplied by xylem parenchyma rich in mitochondria

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


Companion cell in plants are associated with

  • vessels

  • sieve elements

  • sperms

  • guard cells


Assertion : Long distance flow of photoassimilates in plants occurs through sieve tubes.

Reason : Mature sieve tubes have parietal cytoplasm and perforated sieve plates.

  • If both Assertion and Reason are true and the reason is the correct explanation of the assertion

  • If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

  • If Assertion is true statement but Reason is false

  • If both Assertion and Reason are false statements


Vascular bundles of roots are

  • conjoint

  • concentric

  • bicollateral

  • radial


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Ectophloic siphonostele is found in

  • Osmunda and Equisetum

  • Marsilea and Botrychium

  • Adiantum and Cucurbitaceae

  • Dicksonia and Maiden hair fern


Lenticular transpiration takes place in

  • fruits

  • woody stems

  • leaves

  • all of these


When the cell is fully turgid, its

  • DPD = OP

  • DPD = zero

  • WP = TP

  • OP = zero


Short Answer Type

What is the difference between pinocytosis and phagocytosis?


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Multiple Choice Questions

Graham's law is correlated with

  • diffusion

  • osmoregulation

  • osmosis

  • absorption


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