Cell-Surface Membrane Structure
- Created by: sophoverfield
- Created on: 11-11-17 21:53
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- Cell-Surface Membrane Structure
- Phospholipids
- The hydrophilic heads sit inside and outside of the cell
- This creates a bilayer
- The hydrophobic tails face inwards, repelled by water on both sides
- They allow lipid-soluble molecules to diffuse across and also make e membrane self-sealing
- The hydrophilic heads sit inside and outside of the cell
- Proteins
- Carrier proteins
- Bind to ions and molecules like glucose and amino acids
- Allow the transfer of glucose and other big molecules across the membrane
- Channel proteins
- Spans the whole bilayer and is a water-filled channel
- Allow water-soluble substances to diffuse across
- Others
- Some proteins don't extend across the whole bilayer
- Keep the bilayer structure or act as cell receptors for hormones
- Some proteins don't extend across the whole bilayer
- Carrier proteins
- Cholesterol
- Sit within the bilayer and are very hydrophobic
- Prevent water and ion loss from the cell
- Stops too much molecule movement such as the fatty acids but doesn't make it too hard
- Makes the membrane less fluid at high temperature so the cell won't burst
- Glycolipids
- Made up of a carbohydrateand a lipid covalently bonded together
- The carbohydratesection sits outside the cell where it acts as a receptor
- Act as recegonition cells, stability molecules and help cells to attach to one another
- Made up of a carbohydrateand a lipid covalently bonded together
- Glycoproteins
- Chains of carbohydrate which bond to extrinsic proteins of the membrane
- Act as recognition cells for hormones and transmitters
- Also help cells to attach to one another and to recognise other cells
- Phospholipids
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