Biology 9700 · AS & A Level · Genetic technology applied to medicine

Genetic technology applied to medicine — practice question

Using DNA (rDNA) technology, human insulin can be synthesised in a laboratory strain of Escherichia coli. The process begins with insulin mRNA, isolated from human pancreas. Four enzymes are required: reverse transcriptase, DNA polymerase, restriction enzyme, and DNA ligase.
(a(i))[4]

State the function of each enzyme in making rDNA that carries the gene for human insulin: - reverse transcriptase - DNA polymerase - restriction enzyme - DNA ligase

(a(ii))[3]

Outline the role of insulin in a healthy human body.

(a(iii))[2]

Describe and explain one advantage of treating diabetics with human insulin produced by rDNA technology.

(b(i))[4]

With reference to Fig. 3.1, describe how the activity of human insulin differs from that of insulin X.

(b(ii))[2]

Suggest how exchanging the positions of two amino acids in the insulin molecule may cause differences in activity.

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: reverse transcriptase converts mRNA into (c)DNA

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