Question

Which of the following is not a feature of a counter-current mechanism?

(a) Helps in maintaining the concentration gradient

(b) Helps in making the passage of water easier

(c) Helps in concentrating the urine

(d) Helps in diluting the urine

This question was posed to me during an online interview.

The question is from Mechanism of Concentration of the Filtrate topic in chapter Excretory Products and Elimination of Biology – Class 11

Answer 1

Correct choice is (d) Helps in diluting the urine

Explanation: Countercurrent mechanism helps to maintain a concentration gradient in the medullary interstitium. The presence of such an interstitial gradient helps in easy passage of water from the collecting tubule and therefore helps in concentrating the urine.