DP Biology (first assessment 2025)
Question 19M.2.SL.TZ2.2a.ii
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.SL.TZ2.2a.ii |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Outline | Question number | a.ii | Adapted from | N/A |
a.ii.
[Maximum mark: 2]
19M.2.SL.TZ2.2a.ii
(a.ii)
Outline what is indicated by the mitotic index of tissue taken from a tumour.
[2]
Markscheme
a. mitotic index is an indication of the ratio/percentage of cells undergoing mitosis/cell division ✔
b. cancer cells «generally» divide much more than normal «somatic» cells ✔
c. a high/elevated mitotic index in tumours / possible diagnosis of cancer /measure of how aggressive/fast growing the tumour is ✔
Examiners report
Many students could accurately define the term mitotic index. An area of misunderstanding was to categorize the mitotic index as a rate rather than a ratio.
