Question

Active absorption of water by roots is _____.

• A. Along the DPD gradient and with the expenditure of ATP (energy).
• B. Against the DPD gradient and with the expenditure of ATP (energy).
• C. Against the DPD gradient and without the expenditure of ATP (energy).
• D. Along the DPD gradient and without the expenditure of ATP (energy).

Hint:

Active absorption moves water against the DPD gradient and uses metabolic energy.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
Water absorption by roots is passive or active.

Step 2: Passive absorption
In passive absorption, water follows the DPD gradient into the root, driven by transpiration pull, without energy from the root.

Step 3: Active absorption
In active absorption, root cells take up water through their own activity, even against the DPD gradient.
Moving water against the gradient needs metabolic energy from respiration, in the form of ATP.

Final Answer:
Active absorption is against the DPD gradient and uses ATP. \[ \boxed{\text{(B) }\text{Against the DPD gradient and with the expenditure of ATP (energy).}} \]