Question 19M.1A.HL.TZ2.11
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.1A.HL.TZ2.11 |
| Level | HL | Paper | 1A | Time zone | TZ2 |
| Command term | Deduce | Question number | 11 | Adapted from | N/A |
Hershey and Chase used a bacteriophage (a virus that infects bacteria) to investigate the chemical nature of genes. The diagram shows a bacteriophage.
[Source: Graham Knott and Christel Genoud, ‘Commentary: is EM dead?’, Journal of Cell Science (2013),
126: 4545–4552, reproduced with permission. http://jcs.biologists.org/content/126/20/4545.figures-only
doi: 10.1242/jcs.124123 http://www.biologists.com/journal-of-cell-science]
The sulphur in the protein and the phosphorus in the DNA of the bacteriophage were radioactively labelled. The data obtained after bacterial infection and centrifugation are shown in the table.
What did Hershey and Chase conclude from their experiment?
A. DNA was mainly outside the bacterial cells.
B. Viruses infect bacterial cells with proteins.
C. Viral DNA was found within the bacterial cells.
D. Neither protein nor DNA were chemicals making up genes in viruses.
[1]
C
This was a good question, it discriminated very well and was not too difficult.
