A-LevelBiologyInherited change9700/41 · May/June 2023 · Q84 Marks
Fig. 8.1 shows a cell from the testis of a locust at the late prophase I stage of meiosis. [Figure 8.1]
- Explain how the behaviour of the chromosomes in prophase I of meiosis results in the appearance shown in Fig. 8.1.[4]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Mark scheme
Marking points from the official mark scheme (May/June 2023). The mark or mark type is shown in brackets.
- 1 DNA/chromatin / chromosomes / chromatids, condense ;
- 2 homologous chromosomes, pair up / undergo synapsis / form bivalents / form tetrads ;
- 3 crossing-over ;
- 4 between non-sister chromatids ;
- 5 detail of crossing over ;
- 6 chromosomes (stay) joined at, cross-over points / chiasmata ;
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