Question 20N.2.HL.TZ0.b
| Date | November 2020 | Marks available | [Maximum mark: 2] | Reference code | 20N.2.HL.TZ0.b |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Describe | Question number | b | Adapted from | N/A |
Describe what happens to the membranes of an animal cell during mitosis.
[2]
a. nuclear membrane breaks down/disappears (in prophase/at start of mitosis);
b. nuclear membrane reforms around two new nuclei (in telophase/at end of mitosis);
c. plasma membrane pulled inwards at equator / cleavage furrow formed;
d. membrane pinches apart to form two cells / cytoplasm divided / cytokinesis.
The mark scheme allowed candidates to score marks either for describing changes to the nuclear membrane or the role that the plasma membrane plays in cytokinesis. The best answers referred to both. Many of the candidates who wrote about the nuclear membrane had rather sketchy understanding of how it breaks up into small vesicles at the end of prophase and then reforms around both daughter nuclei in telophase.
