A-LEVEL AQA BIOLOGY NOTES
lipids
Lipids
- Fatty acids can be:
- Saturated – there are no C=C bonds and the molecule has as many hydrogen atoms as possible.
- Unsaturated – there is at least one C=C bond, therefore the molecule contains fewer hydrogen atoms than is maximally possible.
- A triglyceride molecule is formed by joining one molecule of glycerol to three fatty acids through three condensation reactions, forming ester bonds.
- Triglycerides have key roles in respiration and energy storage due to its insolubility and high carbon to hydrogen ratio.
- Phospholipids replace one of the fatty acid chains in triglycerides with a phosphate molecule.
- The hydrophobic tails and hydrophilic heads of phospholipids allow them to form phospholipid bilayers.
