Lipids

Question 1

How are triglycerides formed?

Answer 1

1) a condensation reaction

2) where one water molecule is lost

3) and ester linkage is formed between hydroxy group of glycerol and carboxyl group of fatty acid

Question 2

State the structure to function of triglycerides

Answer 2

S1: Higher proportion of C-H bonds than carbohydrates of equal mass
P1: release larger amounts of energy per unit mass when oxidised
F1: more efficient energy storage than carbohydrates

S2: C-H bonds non-polar
P2: does not affect water potential of cells when stored in large amounts
F2: good thermal insulator

S3: weak hydrophobic interactions between fatty acid tails
P3: can slide under pressure
F3: protect vital organs from physical impact

Question 3

State the structure to function of phospholipids.

Answer 3

S1: Amphipathic due to hydrophobic hydrocarbon tails and hydrophilic phosphate head
P1: forms partially permeable cell membrane
F1: effective barrier between cell and external environment

S2: Individual hydrophobic interactions are weak
P2: allow lateral movement of phospholipids
F2: ensuring membrane fluidity