cellular membrane and transport

integral proteins

are spread out across bilayer, act as channels to move large or charged molecules.

peripheral proteins

proteins across cytoskeleton used for signalling

cholesterol

a steroid in the phospholipid bilayer that controls temperature and keeps it flexible.

carbohydrates in cell membrane

act like ID tags on lipids and proteins to help cell recognize invaders

simple diffusion

moves down gradient, no energy required

facilitated diffusion

requires no energy, involves large or charged molecules moving through a carrier or channel protein.

passive transport

requires no energy

active transport

moves up instead of down, requires ATP energy

osmosis

diffusion of water across semipermeable membranes

isotonic

concentration equal inside and out, moves in and out at equal rate

hypertonic

concentration outside is higher than inside, water rushes out

hypotonic

concentration higher inside, water rushes in

protein pumps

form of active transport where proteins in the membrane use atp energy to force molecules across

endocytosis

active transport; membrane engulfs a large or charged particle and vesicles carry it in

exocytosis

active transport; vesicles fuse with cell membrane and spit something out.