EXAM QUESTIONS

Question 1

Describe the hydrolysis reactions involved in the digestion of triglycerides. Do not write about the activity of lipase.

Answer 1

• breaking ester bonds by adding water
• produces 3 fatty acids and a glycerol

Question 2

All mammals produce a lipase called CEL. CEL digest triglycerides. CEL is activated by bile salts binding to the enzyme. Describe two other functions of bile salts?

Answer 2

1. They emulsify lipids
2. Form micelles

Question 3

Mammals feed their young on milk. CEL digests the triglycerides in milk. The ability to produce CEL occurred due to a gene mutation. Describe how natural selection may have led to all mammals in a population producing CEL.

Answer 3

• random mutation results in producing a new allele, those with new allele produce more CEL
• they are more likely to survive now that they are able to digest milk so can reproduce more and pass on that allele
• directional selection then increases the frequency of this surviving allele in the population

Question 4

What is a species?

Answer 4

A group of similar organisms that can interbreed and produce fertile offspring