Cell Transport

Learning Objectives Describe passive transport. Describe active transport.

Passive Transport: Diffusion

Cell Membrane

Inside Cell

Outside Cell

Solutes

Higher concentration of solute on one side of the membrane than the other

Diffusion causes net movement of solute particles toward side of membrane with lower concentration.

At equilibrium, particles move equally in both directions, so there is no net change.

Passive Transport: Facilitated Diffusion

Passive Transport: Osmosis

aquaporin

water

cell membrane

sugar

Osmosis

Osmosis in Cells

Isotonic Hypertonic Hypotonic

Active Transport

Protein pumps Endocytosis Exocytosis

Endocytosis

Active Transport vs. Diffusion

Compare and contrast active transport and diffusion.