Membrane transport

Science

Definition

Membrane transport refers to the mechanisms by which substances move across the cell membrane. Passive transport (diffusion, osmosis, facilitated diffusion) requires no energy and moves substances down their concentration gradient, while active transport uses ATP to move substances against their gradient.

Examples

  • Oxygen diffusing from the lungs into blood capillaries
  • Sodium-potassium pump actively transporting ions to maintain nerve cell potential
  • Aquaporins facilitating rapid water movement across kidney cell membranes

Related Terms

Cell membrane Cell transport Cell organelles Atp cycle

Study This Concept

Practice membrane transport with free review games in these units:

AP Biology Unit 2: Cell Structure and Function