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Question 19M.3.SL.TZ1.a

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Date May 2019 Marks available [Maximum mark: 3] Reference code 19M.3.SL.TZ1.a
Level SL Paper 3 Time zone TZ1
Command term Outline Question number a Adapted from N/A
a.
[Maximum mark: 3]
19M.3.SL.TZ1.a

Some bacterial genes are used as marker genes. Outline the use of marker genes in genetic modification.

[3]

Markscheme

a. named example of a marker gene, eg: ampicillin resistance ✔

b. target gene and marker gene combined «in the same construct» ✔

c. taken up by host ✔

d. evidence of the marker gene measurable ✔

e. indicates successful gene modification/incorporation ✔

Examiners report

Marker genes were often described as desired or target genes in gene transfer and their role was not understood. No reference to antibiotic resistance genes was seen.

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