Multiple Choice Questions

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If turgor pressure becomes equal to the wall pressure, then

  • water leaves the cell

  • water enters the cell

  • no exchange of water takes place

  • solute goes from the cell into water


C.

no exchange of water takes place

Turgor pressure is the pressure that develops in a cell from time to time due to osmotic diffusion of water molecules into a cell resulting in the stretching of cell wall. Due to turgor pressure, rigid cell wall offers resistance. This resistance works in a direction opposite to turgor pressure. But it is equal to turgor pressure and is called wall pressure. In this condition, no exchange of water takes place.


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Match the following and choose the correct option.

Column I Column II
A. Water potential i.  It is usually positive
B.  Solute potential  ii.  It is zero for pure water
C. Pressure potential iii.  It is always negative

  • A - ii; B - iii; C - i

  • A - i; B - iii; C - ii

  • A - iii; B - ii; C - i

  • A - ii; B - i; C - iii

  • A - ii; B - i; C - iii


Which of the following statements about the mass flow hypothesis is wrong?

  • It is the accepted mechanism for translocation of sugars from source to sink

  • As glucose is prepared at source it is converted to sucrose

  • Sucrose is actively loaded into a sieve tube

  • The process of loading at source produces a hypotonic condition in the phloem

  • The process of loading at source produces a hypotonic condition in the phloem


Which of these is/are not a property of facilitated transport?

(A) Requires special membrane proteins 

(B) Highly selective 

(C) Uphill transport 

(D) Requires ATP energy

  • (A) and (B) only

  • (C) and (D) only

  • (A) and (C) only

  • (B) and (C) only

  • (B) and (C) only


Good soil is :

  • which holds whole of the water that enters into it

  • which allows percolating the water slowly from it

  • which allows water to pass very quickly from it

  • which allows limited amount of water to retain into it


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Wooden doors swell up and get stuck during the rainy season. This is due to the phenomenon of

  • imbibition

  • endosmosis

  • capillarity

  • deplasmolysis


In plants, water moves from

  • less negative to more negative potentia

  • more negative to less negative potential

  • same potentials

  • none of the above


Choose the wrong statement

  • Cells swell in hypertonic solutions and shrink in hypotonic solutions

  • Water potential is the kinetic energy of water which helps in the movement of water

  • The absorption of water by seeds and dry wood takes place by a special type of diffusion called imbibition

  • Solute potential or PS is always negative

  • Solute potential or PS is always negative


Which of the following statements about plasmolysis is/ are true?

I . Plasmolysis occurs when water moves into the cell.

II. Cells shrink in hypotonic solutions.

III. If the external solution balances the osmotic pressure of the cytoplasm, it is said to be isotonic.

  • I only

  • II only

  • III only

  • I and II only

  • I and II only


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Assertion : A plant girdled upto bast will die.

Reason : Food transportation in such plant will cease followed by ceasation of water transport.

  • If both Assertion and Reason are true and Reason is the correct explantion of Assertion

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

  • If Assertion is true but Reason is false

  • If Assertion is false but Reason is true


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