Date | November 2017 | Marks available | 1 | Reference code | 17N.3.HL.TZ0.03 |
Level | Higher level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
Command term | State | Question number | 03 | Adapted from | N/A |
Question
The Hershey and Chase experiment supported DNA as the hereditary material. Describe the experiment.
Some regions of DNA act as telomeres or produce tRNA. State one other function of DNA sequences that do not code for protein.
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. regulate gene expression
b. act as promoter
c. role in chromosome pairing/crossing over/recombination
d. introns
OWTTE
[Max 1 Mark]