IB Biology HL A1.2.14 Hershey-Chase Question Bank

Practise IB Biology HL A1.2.14 by interpreting radioactive-label and centrifugation data to evaluate DNA as genetic material.

Exam points

Explain how 32P labels DNA and 35S labels protein in bacteriophage experiments.
Interpret centrifugation data to show labelled DNA entered bacteria after infection.
Evaluate how the evidence supports DNA rather than protein as genetic material.

[Maximum number: 3]

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

Describe the experiment.

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

b. proteins labelled with radioactive sulphur ${ }^{35} \mathrm{~S}$ and DNA labelled with radioactive phosphorous ${ }^{32} \mathrm{P}$

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

3 max

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A1.2.14 (HL)—Hershey-Chase experiment question 1