Question

Normal homeostatic conditions require potassium concentrations to be about 1000 times higher inside the cell than in the blood.

What mechanism does a cell use to move these small potassium molecules into the cell against the concentration gradient?

passive transport by osmosis
active transport by proteins
passive transport by diffusion
active transport by endocytosis

Answer 1

Active transport by proteins.

Answer 2

The correct answer would be active transport by proteins.

When a molecule is transported against the concentration gradient it requires cellular energy and the process is termed as active transport.

The energy is either provided by the hydrolysis of the ATP (adenosine triphosphate) in primary active transport or by the electrochemical gradient in secondary active transport

Active transport takes place with the help of integral membrane proteins or transport proteins which form carriers or channels across the membrane.

Examples may include a sodium-potassium pump, uptake of glucose in small intestine et cetera.