DP Biology (first assessment 2025)
Question 23M.2.HL.TZ2.a
Date | May 2023 | Marks available | [Maximum mark: 4] | Reference code | 23M.2.HL.TZ2.a |
Level | HL | Paper | 2 | Time zone | TZ2 |
Command term | Explain | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 4]
23M.2.HL.TZ2.a
Explain how changes to the cell cycle can result in tumour formation.
[4]
Markscheme
- cell cycle is (repeated) sequence of cytokinesis/cell division, (then) interphase(then) mitosis / cell cycle includes the sequence of interphase, mitosis and cytokinesis/cell division (to form new cells which repeat the cycle)
- cyclins control/regulate this cycle / ensure the cell moves on to the next stage of the cycle when it is appropriate
- extra cells produced when they are needed
- tumour formation is the result of uncontrolled cell division/ cells growing and dividing endlessly
- repeated mitoses/high mitotic index
- due to mutations in oncogenes / oncogenes may become active and contribute to the development of a cancer cell
- carcinogens/radiation/mutagenic chemicals/mutagens/smoking cause mutations/tumours;
