Lipids

Question 1

Describe the structure and properties of glycerol and fatty acids (in lipids).

Answer 1

Glycerol:
- Molecular formula C3H8O3. Three-carbon alcohol, with each carbon bearing a hydroxyl (OH) group.
- Soluble in water because of its polar -OH group.

Fatty acids:
- Carboxylic acids (An acidic hydrophilic carboxyl (COOH) functional group at one end & an attached hydrophobic hydrocarbon chain)
- Possess long carbon skeletons (between 12-20 carbons). Each carbon joins to hydrogen atoms.
- Fats are hydrophobic due to abundance of non-polar C-H bonds.

Question 2

Describe the formation and breakage of ester bonds.

Answer 2

Formation: Condensation reaction where small molecules are combined to form larger molecules with the formation of water molecule

Breakage: Hydrolysis reaction where large molecules are broken into smaller molecules with the addition of water.

Question 3

Describe the structures and properties of triglyceride. Explain how these are related to its roles in living organism.

Answer 3

1. Higher proportion of C and H atoms compared to O atoms. (Triglycerides contain a greater number of carbon atoms per unit mass than carbohydrates)
   - More efficient energy stores than carbohydrates, releases a larger amount of energy. (1g of fat releases 38kJ/g of energy, 1g of carbohydrates releases 17kJ/g of energy)
2. Highly reduced molecules