What is a concentration gradient ?

The counter current mechanism helps to maintain a concentration gradient. This gradient helps in -

Counter-current mechanism helps to maintain a concentration gradient in the medullary interstitium. Presence of such interstitial gradient helps in an easy passage of water from the

Mention the substances that exit from the tubules in order to maintain a concentration gradient in the medullary interstitium.

[A] : Active transport results in solute movement against a concentration gradient . [R] : Acitve transport of Na^(+) , K^(+) is energized by ATP .

A transport which is carried out by membrane prote ins and uses energy to pump molecules against a concentration gradients is

Na^+ – K^+ pump (A) Transports 3Na^+ inwards & 2K^+ outwards. (B) Maintain ionic gradients by active transport. (C) Works against a concentration gradient. How many of above statements are false ?

Assertion :- Human kidneys can produce urine nearly four times concentrated than the initial filtrate formed. Reason :- Counter current mechanism helps to maintain a concentration gradient in the medullary interstitium.

[A]: Active transport results in solute move- ment against a concentration gradient. [R]: Active co-transport of Na^+ and K^+ is ener-gized by ATP.