membrane permeability

ability of membrane to allow substances to pass through

what does membrane permeability mean?

no, it’s semi-permeable (selective permeability)

does the membrane allow anything to pass through?

phospholipid bilayer

cell membranes are selectively permeable due to their what?

small and less charged molecules

easier to pass through the bilayer

bigger and more charged molecules

harder to pass through the bilayer

temperature

increasing what increases permeability?

nonpolar

nonpolar vs polar: which molecules passes throught more easily?

protein channels, carriers, and pumps

integral proteins that help facilitate movement of specific substances across the membrane

active and passive transport

how substances cross membrane

active transport

requires ATP

passive transport

doesn’t require energy

simple and facilitated diffusion

types of diffusion of passive transport

simple diffusion

small, nonpolar molecules move directly across membrane down their concentration gradient

facilitated diffusion

passive movement of molecules across membrane with help of membrane proteins, (channel or carrier proteins)