Cell membrane & Transport

Question	Answer
what is the usual distance across the plasma membrane?	1-9 nanometres
what is the main role of the plasma membrane?	to control the entry an exit of materials
why is a phospholipid bilayer called a bilayer?	the phospholipids arrange themselves in a double layer with the phosphate heads facing out and the fatty acid tails facing inward
the plasma membrane consists mainly of what?	phosphoplipds and proteins
what is the role of the phospholipids?	forms a bilayer preventing entry of water soluble substances such as glucose. allow entry of lipid soluble substances such as oxygen and glycerol
role of extrinsic proteins	only found on outer surface of membrane - provides support
role of intrinsic proteins	act as channels and carriers for polar molucles to enter and exit the cell
role of glycolipids	carb and a lipid - involved in cell recognition
role of glycoproteins	carb and a protein form recognition sites
role of cholesterol	type of lipid beween phosphopilid bilyer - more cholesterol controls rigidity of membrane
why is it called fluid mosaic model?	described as fluid as the components are free to move around and it is described as mosaic as proteins are scattered in the lipid layer.

Resource summary

	Created by paigexmonks over 11 years ago