DP Biology (last assessment 2024)
Question 17N.3.HL.TZ0.03a
| Date | November 2017 | Marks available | [Maximum mark: 3] | Reference code | 17N.3.HL.TZ0.03a |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Describe | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 3]
17N.3.HL.TZ0.03a
(a)
The Hershey and Chase experiment supported DNA as the hereditary material. Describe the experiment.
[3]
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]
