Simple Diffusion and Active Transport

hypertonic

"above strength" when concentrations are higher inside of the membrane

hypotonic

"below strength" when concentrations are lower on the inside of the membrane

isotonic

"same strength" when concentrations are the same on both sides of the membrane

down the [ ] gradient

going from an area of high concentration to low concentration.

up the [ ] gradient

going from an area of low concentration to high concentration.

diffusion

movement of molecules from an area of higher concentration to lower concentration until equilibrium is reached.

passive transport

no energy required

facilitated diffusion

process in which molecules that cannot directly diffuse across the membrane pass through special protein channels.

osmosis

an example of facilitated diffusion. the diffusion of water through a selectively permeable membrane.

aquaporins

water channel proteins that allow water to pass right through the membrane.

simple diffusion

Molecules will move down the concentration gradient (high to low).

factors affecting rate of diffusion

temp., pressure, size of molecule, and steepness of [ ] gradient