Unit 1 - biological molecules

Question 1

Uses of lipids

Answer 1

Source of energy
Water proofing
Insulation
Protection

Question 2

Use of lipid waterproofing

Answer 2

Plants and insects have waxy cuticles to conserve water.

Animals secrete lipids

Question 3

Lipids in insulation

Answer 3

Slow conductors of heat so conserve body heat.

Bad electrical conductors, so myelin sheath around axons.

Question 4

Lipids in protection

Answer 4

Fat is stored around delicate organs

Question 5

Constituent parts of triglycerides

Answer 5

Glycerol and three fatty acids joined in condensation reaction.
Joined by ester bonds.
Unsaturated

Question 6

Advantages of triglycerides

Answer 6

Good source of energy due to low mass:energy ratio.
High hydrogen:oxygen ration so H2O is released when oxidised, which is important is desert locations.
Large, non-polar and insoluble in water.