membrane stuff Flashcards
key stuff about membranes
what are cell surface membranes mainly comprised of?
phospholipids
why can phospholipids form bi layers?
as they have a polar head and a non polar tail
what is the function of cholesterol
regulates membrane fluidity
name two things glycoproteins and glycolipids do
.act as self antigens
.help join cells together
why is diffusion a passive process
as it only requires the energy of the particles themselves and no energy in the form of ATP
what is osmosis
osmosis-movement of water across a partially permeable membrane from high water potential to low water potential until dynamic equilibrium has been reached.
what are the units of water potential
Kpa
what is the highest water potential?
0Kpa
what is active transport?
the movement of partcles from a low to high concentration
why is active transport an active process?
As it requires energy in the form of ATP
how phospholipids arranged in the bilayer of a membrane?
the hydrophobic tails point inwards the hydrophillic heads point outwards
name three factors that affect rate of diffusion
temperature,surface area,diffusion distance
what happens to a red blood cell if it loses too much water
water leaves the cell and the cell shrinks
what happens to a red blood cell if it gains too much water
it undergoes haemolysis(bursts)
what is the function of cell surface membranes
they are a barrier between the cell and it’s enviroment
they control what substances can enter and exit the cell
