cell membrane + transport

Cell Membrane

• maintains homeostasis
• made of phospholipid bilayer
• semi-permeable
• amphipathic

phospholipid bilayer

phospho = phosphate head
lipid = fatty acid tail
bilayer = 2 layers

phosphate head

hydrophilic head (water good)

hydrophobic tail

lipid/fatty acid tail

diffusion

movement of particles from high to low concentration

• passive transport

osmosis

diffusion of water

• passive transport

facilitated diffusion

diffusion with protein doorway

equilibrium

balance - particles move but no change in concentration

passive transport

• high to low concentration
• no energy used

active transport

• low to high concentration
• energy used

exocytosis

• active transport
• moves stuff out of cell

endocytosis

• active transport
• moves stuff into cell

ampiphathic

• hydrophilic and hydrophobic parts

particles pass through easier if

• small

• nonpolar

• uncharged

semi permeable

some stuff can get through

isotonic solution

same solute concentration as cell

hypotonic solution

• less solute concentration than cell

• solution moves into cell

• cell may burst

hypertonic concentration

• higher solute concentration than cell

• solution moves out of cell

• cell shrivels