Question

Which one of these is NOT an example using facilitated diffusion?
Aquaporins facilitate the diffusion of water in the kidney tubules of many
mammals.
A carrier protein moves sucrose across the membrane with the
concentration gradient.
Using the sodium-potassium pump involves the hydrolysis of ATP and the
release of Nat to the outside of the cell.
Ca+2 moves from high cytoplasmic concentration to low concentration
inside the cell using a membrane-spanning protein.

Answer 1

Answer:

C. "Using the sodium-potassium pump involves the hydrolysis of ATP and the

release of Nat to the outside of the cell."

Explanation:

The use of a sodium-potassium pump is a form of active transport, not diffusion. It also requires energy because the pump moves ions against their concentration gradient (low to high), unlike diffusion.

Answer 2

Answer:

Using the sodium-potassium pump involves the hydrolysis of ATP and the

release of Na+ to the outside of the cell.

Explanation:

Facilitated diffusion is a type of passive transport. Molecules are moved from higher to lower concentration hence the process does not require energy or ATP. It does require a pore or channel to facilitate the process.

Out of the given options, sodium potassium pump is not an example of facilitated diffusion since it is hydrolysing ATP and using energy for the movement of Na+ ions against the concentration gradient. It is an example of active transport.