CBSE Questions for Class 11 Medical Biology Transport In Plants Quiz 8 - MCQExams.com

• Osmotic potential refers to the effect of dissolved solutes on the water potential.
• Since electrolytes dissociate into their component ions; the increased number of dissolved particles as compared to the non-electrolytes imparts more reduction in the water potential of a solution with reference to the state of pure water. 
• So, the osmotic potential of the electrolyte is more than that of non-electrolytes.
  Hence, the correct option is A.

• Water potential is the potential energy of water per unit volume with respect to pure water on the addition of solute the water potential decreases. 
• As pure water has negligible solutes so it has maximum water potential.
• Osmotic potential is the ability of the water to move from a hypotonic solution to a hypertonic solution across a semi-permeable membrane. 
• So, pure water has zero osmotic potential as when there is lesser solute the water is less likely to move by osmosis. 

• Gaseous exchange is necessary for plants for the purpose of photosynthesis and respiration. 
• For this purpose, stomata are present on leaves.
• Stomata are the pores present on the epidermal layer of the plant leaf. 

During the beginning stage of the germination, the seeds take up water rapidly and this results in swelling and softening of the seed coat at an optimum temperature. By rupturing of the seed coats helps to emerge the radicle and the plumule to form a primary root. This stage is referred to as an imbibition. So, the correct answer is ‘Imbibition’.

A. Sieve plates – the septa present between two adjacent sieve tubes, meant for translocation of solutes.

B.Pits – thin areas present on the secondary cell wall, meant for intercellular transportation.

C. Stomata – small pores, present on the epidermis of aerial organs meant for transpiration and exchange of gases.

D.Lenticels – the large sized, slightly raised spots or aerating pores present on the surface of cork, meant for exchange of gases.

• Facilitated transport or diffusion or passive-mediated transport can be defined as the process of spontaneous passive transport of molecules or ions across a cell membrane through the specific transmembrane integral proteins.
  
• It does not require the ATP molecules and is the diffusion is downhill.
• So, the correct answer is 'c and d only'.

• Simple diffusion can be defined as the process by which solutes particles are moved along the concentration gradient through the semipermeable membrane (cell membrane)
• Eg- water, oxygen, carbon dioxide, ethanol and urea are transported by simple diffusion.
• This type of transport does not require energy for the transport of molecules across the cell membrane. 
• So, the correct answer is 'Simple diffusion'.

Imbibition is a special type of diffusion when water is absorbed by solids-colloids causing an enormous increase in volume. Examples include the absorption of water by seeds and dry wood.

When moistened mustard seeds are kept in a corner in a bottle then due to imbibition,  seeds will absorb water and suddenly blew up.

So the correct answer is 'Imbibition'.

A. Correct option is (A)
B. Explanation for the correct option.

• When a molecule moves across a membrane independent of another molecule, it is called uniport.
• When two molecules move simultaneously across the membrane in the same direction, it is called symport.
• When two molecules move in the opposite directions to each other across the membrane, it is called antiport.