- composed of lipids, proteins and carbohydrates
FLUID MOSAIC MODEL
- Controls entry and exit: proteins that allow water-soluble substances in and out.
- Forms a barrier against water-soluble substances:phospholipid molecules have a hydrophilic head; hydrophobic tail→ arrange themselves in a bilayer.
- Allows cell communication: receptor proteins detect chemicals released from other cells→ response is carried out.
- Allows cell recognition: gylcoproteins and glycolipids→ WBC recognises cell as your own→ no immune response carried out on own cells.
- Is fluid: cholesterol fits in between bilayer- reduces fluidity- more rigid; prevents it from breaking up.
1 of 4
Lipids in Membranes
- one molecule of gylcerol; 3 fatty acids
- fatty acids have long tails made of hydrocarbons (hydrophobic)
- Saturated: single bonds between carbon atoms
- Unsaturated: double bonds between carbons: the more unsaturated the more fluid the membrane is.
- formed by condensation reaction
- ester bond formed
- H2O released
2 of 4
One phosphate group- hydrophilic
Two Fatty acids
One glycerol molecule
3 of 4
- shake sample with ethanol: dissolve the lipids.
- pour in water- lipids can't dissolve in water
- creamy emulsion appears is lipids are present.
4 of 4