Cambridge International A Level Biology Revision Guide

Chapter 5: The mitotic cell cycle
3 A cell with four chromosomes undergoes a cell cycle including mitosis. Which diagram correctly shows
the changes in chromatid number during interphase?
2 chromatids 4 chromatids 4 chromatids 8 chromatids
S phase
S phase
S phase
S phase
mitosis
cell
division
mitosis
cell
division
mitosis
cell
division
mitosis
cell
division
4 chromatids 2 chromatids 8 chromatids 4 chromatids
A
B
4 Distinguish between the following terms: centrosome, centriole and centromere. [6]
5 The diagram shows three cells (labelled A, B and C) from a root tip which have been stained to
show chromosomes.
C
D
[1]
107
A B C
a Identify the stage of mitosis shown by each cell. [3]
b Describe what is happening at each stage. [3]
[Total: 6]
6 a Diagram 1 below shows a plant cell dividing by mitosis. Only two of the many chromosomes
are shown for simplicity.
1 2
cell wall
spindle
fibres
nuclear
envelope
reappears
remains of
spindle
new cell wall
forming
across cell
b
i What stage of mitosis is shown? [1]
ii Draw prophase for the same cell assuming the cell has only two chromosomes, as in diagram 1. [1]
Diagram 2 shows the same cell at telophase. The cell is beginning to divide and a new cell wall is forming,
spreading out from the middle of the cell. Copy the diagram and add drawings of the chromosomes as
they would appear at this stage. [1]