Question

which of the following is an example of active transport?
all of these
movement of potassium with the concentration gradient
movement of potassium from a low concentration to a high concentration
movement of sodium from a high concentration to a low concentration

Explanation:

Active transport is the movement of molecules against their concentration gradient (from low to high concentration) using energy (usually ATP). Movement with the concentration gradient (high to low) is passive transport.

• Movement of potassium with the concentration gradient is passive transport.
• Movement of sodium from high to low concentration is passive transport.
• Movement of potassium from low to high concentration is active transport. Since “ALL of these” includes incorrect passive - transport examples, it is wrong.

Answer:

Movement of potassium from a low concentration to a high concentration