Cell Membrane/ Diffusion

 

Cell membrane in eukaryotic cells is selectively permeable

            Composed of a phospholipid bilayer studded with proteins

            Some things can leak right through

            Those that cannot require transport proteins

                        active transport

                        passive transport

 

Diffusion = passive transport down a concentration gradient

            Why do things spread out?

                        They are above absolute zero in temperature

                        They are not bound together