B1.1.8-9

Question 1

Explain why lipids are hydrophobic.

Answer 1

Lipids have long hydrocarbon chains, which are non-polar and do not interact with water molecules, making them insoluble in water.

Question 2

Outline the structure and function of fats

Answer 2

Structure: Fats consist of one glycerol molecule (a small three-carbon molecule) connected to three fatty acids (long chains of carbon atoms bonded to hydrogen).
Function: Fats are used for energy storage, insulation, and protection of organs.

Question 3

Outline the structure and function of waxes

Answer 3

Structure: Waxes are similar to fats but instead of glycerol, they have long-chain alcohols attached to fatty acids.
Function: Waxes form protective layers, providing waterproofing (e.g., on leaves or feathers).

Question 4

Outline the structure and function of steroids

Answer 4

Structure: Steroids have a four-ring structure made of carbon atoms (like a set of fused rings). Examples include cholesterol, testosterone, and estrogen.
Function: Steroids are involved in membrane structure (cholesterol) and act as hormones (e.g., testosterone, estrogen).

Question 5

Explain the condensation reaction connecting fatty acids and glycerol to form a triglyceride.

Answer 5

One glycerol molecule links with three fatty acids to form a triglyceride, releasing water.

Question 5

Explain the condensation reaction connecting fatty acids, glycerol and a phosphate group to form a phospholipid.

Answer 5

glycerol binds two fatty acids and a phosphate group attaches to the third glycerol carbon, creating an amphipathic molecule with a hydrophilic head and hydrophobic tails.