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Date November 2017 Marks available 3 Reference code 17N.3.HL.TZ0.03
Level Higher level Paper Paper 3 Time zone TZ0 / no time zone
Command term Describe Question number 03 Adapted from N/A

Question

The Hershey and Chase experiment supported DNA as the hereditary material. Describe the experiment.

[3]
a.

Some regions of DNA act as telomeres or produce tRNA. State one other function of DNA sequences that do not code for protein.

[1]
b.

Markscheme

a. radioactive isotopes used to label viruses/bacteriophages/phages

b. proteins labelled with radioactive sulphur/35S and DNA labelled with radioactive
phosphorous/32P

c. phage infects bacterium

d. only viral DNA enters bacterium «viral coat/capsid/shell do not»

e. parts of phage remaining outside bacterial cell are removed

    OR

    bacteria are separated from phage parts «by centrifuge»

f. bacteria contain the labelled/radioactive DNA

[Max 3 Marks]

a.

a. regulate gene expression

b. act as promoter

c. role in chromosome pairing/crossing over/recombination

d. introns

OWTTE

[Max 1 Mark]

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Additional higher level » Topic 7: Nucleic acids » 7.1 DNA structure and replication
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Additional higher level » Topic 7: Nucleic acids
Additional higher level

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