Cell membranes

PLASMA membranes
1. barrier, control what enters and leaves cell
2. partially permiable
what gives cell membranes their different properties?
1. phospholipid
  1. they have a hydropillic head and a hydrophobic tail
  2. they form a bilayer
    1. the centre is hydrophobic preventing water from entering or leaving
  3. fat soluble substances can enter
2. cholesterol
  1. lipid, present in all cell membranes but bacterial cell membranes
  2. fit between phospholipids, making the membrane more rigid
3. glycolipids and protiens
Cell membrane permiablity
1. temperature
diffusion
1. net movement of particles from higher to lower concentration dow the concentration gradient
2. happens over phospholipid bilayer
3. how to increase the rate of diffusion
  1. steeper conc gradient
  2. thinner exchange surface
  3. increased temperature
  4. larger s.a

Resumo de Recurso

	Criado por lily wilson mais de 3 anos atrás