- controls how substances move in and out of a cell.
- made of phospholipids, carbohydrates and protiens.
- called a fluid mosaic structure cos the phospholipids for a flexible sheet, protiens float in the sheet and the carbs extend out from the protiens.
- phospholipds are arranged in a bilayer. polar hydrophillic phosphate heads facing towards the water, non polar hydrophobic fatty acid tails facing each other in the middle.
- protiens have hydrophillic amino acids in contact with water out of the membranes, hydrophobis amino acids in contact with the fatty chains inside the membrane.
transport protiens: take place through integral protiens, inculed f.d and a.c
receptor protiens: on the outside of p.m have a specific binding site.
recognition protiens: involved in cell recognition (glycoprotiens)
strucural protiens: inside p.m attached to the cytoskeleton, involved in maintaning / changing the cells shape. on the outside of p.m used in cells adhesion.
- the carbs are on the outer surface of the p.m, carbs with protiens attached to them are glycoprotiens, phospholipids joined to carbs are called glycolipids.