DP Chemistry (last assessment 2024)
Question 18M.3.hl.TZ1.19
| Date | May 2018 | Marks available | [Maximum mark: 4] | Reference code | 18M.3.hl.TZ1.19 |
| Level | hl | Paper | 3 | Time zone | TZ1 |
| Command term | Describe, Outline | Question number | 19 | Adapted from | N/A |
19.
[Maximum mark: 4]
18M.3.hl.TZ1.19
Radiotherapy is one type of treatment for cancer.
(a)
Describe how ionizing radiation destroys cancer cells.
[2]
Markscheme
Any two of:
radiation causes breaks in DNA chains
OR
radiation causes errors in DNA sequences
«damage accumulates and» cells cannot multiply
rapidly dividing/cancer cells more susceptible
Accept “alters DNA”.
[2 marks]
(b)
Outline how Targeted Alpha Therapy (TAT) is used for treating cancers that have spread throughout the body.
[2]
Markscheme
Any two of:
radiation source delivered directly to «targeted» cancer cells
by a carrier drug/protein/antibody
several sites in body can be targeted «at same time»
[2 marks]