Question

Active transport involves the transport of molecules across a cell membrane.
In order to establish and maintain a concentration gradient, which of the following condition is suitable?

• A. Free energy is used to drive molecules back-and-forth across the transmembrane protein.
• B. Free energy is used to drive molecules and across a transmembrane protein against the concentration gradient.
• C. No free energy is required.
• D. There must be an equal quantity of molecules on both sides of the membrane.

Answer 1

The correct option is B Free energy is used to drive molecules and across a transmembrane protein against the concentration gradient.

Free energy obtained from hydrolysis of ATP is used for the movement of solutes against their concentration gradient across the plasma membrane using a transport transmembrane protein also called pump

So, the correct answer is 'Free energy is used to drive molecules and across a transmembrane protein against the concentration gradient'