Biology 9700 · AS & A Level · Principles of genetic technology

Principles of genetic technology — practice question

Conventional methods for genetically modifying organisms rely on three enzymes: restriction endonuclease, reverse transcriptase and DNA ligase. These enzymes have been used to make genetically modified (transgenic) pigs that carry the GFP gene coding for green fluorescent protein, which was originally obtained from jellyfish.
(a)[3]

Outline how these three enzymes could be used to genetically engineer a transgenic pig carrying the GFP gene.

(b)[2]

Explain why the GFP gene was chosen for testing the new technique.

(c(i))[1]

Calculate the percentage of zygotes in the control group that were transgenic. Show your working.

(c(ii))[1]

Explain whether the percentage you calculated in (i) is above or below the expected value.

(c(iii))[1]

Name a statistical test that could be used to check whether the difference between the percentage you calculated in (i) and the expected percentage is significant.

(c(iv))[3]

State the most suitable concentration of Cas9 nuclease and guide RNA for causing a deletion in the $GFP$ gene, and justify your choice.

(d)[3]

Explain what Fig. 5.1 shows about how successful the new technique was in creating a deletion in a pig gene so that the pigs are resistant to PRRSV.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: restriction endonuclease cuts open the plasmid/vector

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