Question

Which process occurs against a concentration gradient of solute?
A. Diffusion
B. Osmosis
C. Transpiration
D. Translocation

Answer 1

Hint: A concentration gradient created where the concentration of solute is more in one area as compared to another area. Concentration means the amount of solute as compared to solvent.

Complete answer:
In diffusion, molecules move randomly, the net result being substance moving from regions of higher concentration to a region of low concentration.
In osmosis, the solvent moves from an area of low solute concentration to high solute concentration across the semipermeable membrane.
Transpiration is the loss of water from the leaves through the stomata.
The bulk movement of a substance through the conducting or vascular tissues of plants is called translocation.
In the case of the concentration gradient of solute, the movement of the molecules is from the higher concentration to lower concentration. However, in the case of osmosis, it is opposite. In that case, the solvent molecule moves from the lower concentration to higher concentration.
Hence, from the above, the discussion osmosis process occurs against a concentration gradient of solute.

Therefore, the correct answer is option B.

Additional information: Plants obtained their nutrients from the surrounding especially from the water and soil. The movement of these nutrients from the environment into the plant and also from one plant cell to another cell essentially involves movement across a cell membrane. Transport across the membrane can be through diffusion, facilitated transport and active transport. In living organisms, the transportation of the nutrient across the cell membranes can be done by two modes that are passive transport which includes diffusion and osmosis and active transport.

Note:
Suppose, salt is dumped into a water tank containing water. The corner where the salt has dumped would have a higher concentration as compared to other corners. Therefore the solute molecules move down their concentration gradient to equal the concentration in both the corners. So it moves from higher concentration to low concentration.