Plasma Membranes

• 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.

TRIGLYCERIDE

• one molecule of gylcerol; 3 fatty acids
• fatty acids have long tails made of hydrocarbons (hydrophobic)

FATTY ACIDS

• Saturated: single bonds between carbon atoms
• Unsaturated: double bonds between carbons: the more unsaturated the more fluid the membrane is.

TRIGLYCERIDE FORMATION

• formed by condensation reaction
• ester bond formed
• H2O released

One phosphate group- hydrophilic

Two Fatty acids

One glycerol molecule

• shake sample with ethanol: dissolve the lipids.
• pour in water- lipids can't dissolve in water
• creamy emulsion appears is lipids are present.