Cellular Transport

There are four types of cellular transport: diffusion, osmosis, facilitated diffusion, and active transport.

• Diffusion is the process by which substances travel across a membrane from higher concentrations to lower concentrations. This process occurs until both sides are balanced, and it doesn't use ATP
• Osmosis is the diffusion of water.
• Facilitated diffusion- via special protein channels, molecules can cross a semipermeable or imperial membrane down the concentration gradient.
• Active transport moves from low to high on the concentration gradient and uses ATP.
• Ion pumps move ions across a plasma membrane from low to high on their concentration gradient. These pumps use ATP.
• In endocytosis, cells absorb proteins and other substances by surrounding them.
• In exocytosis, material is discharged by vesicles at a cell's surface.