Contents of the Membrane
- Created by: _laurenb
- Created on: 11-04-15 20:34
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- Content of the membrane
- Phospholipid - form the phospholipid bilayer
- Hydrophilic phosphate head on the outside of the bilayer; faces the cytoplasm or outside of the cell
- Stop ions and large permeable molecules from passing through by being impermeable to them
- Are permeable to non-polar molecules such as fatty acids and oxygen
- Are permebale to polar molecules such as carbon dioxide, watser and alcohol
- Hydrophobic hydrocarbon tail which faces the inside of the bilayer
- Allow movement so that vesicles can move and rejoin
- From a barrier for water-based substances between the cytoplasm and extracellular fluid
- Hydrophilic phosphate head on the outside of the bilayer; faces the cytoplasm or outside of the cell
- Proteins
- Extrinsic proteins which are on one side of the bilayer only
- Act as enzymes in some membranes
- Intrinsic proteins which span the whole bilayer
- Act as channel and carrier molecules
- Act as receptors for chemicals such as hormones
- Extrinsic proteins which are on one side of the bilayer only
- Cholesterol
- Are found only in eukaryotic cells
- Helps to stabilise the membrane by making the head and tail of the phospholipid bind together
- Reduces permeability to water and non-polar molecules
- Stops the phospholipids from solidifying at low temperatures and becoming too fluid at high temperatures
- Are found only in eukaryotic cells
- Carbohydrates
- Form glycoproteins when joined with proteins
- Allow cell adhesion by making the cells in a tissue stick together
- Form glycolipids when joined with phospholipids
- Allow cell signalling by acting as a receptor
- Act as a recognition site for cells such as leucocytes
- Form glycoproteins when joined with proteins
- Phospholipid - form the phospholipid bilayer
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