Exam Focus: 6-Mark "Describe the Stages of Mitosis" Questions

🎯 Exam Focus: 6-Mark "Describe the Stages of Mitosis" Questions

Questions asking you to "describe the stages of mitosis" are among the most common 6-mark questions for this topic. Here is exactly what examiners want to see:

• Prophase: Chromosomes condense and become visible; nuclear envelope breaks down; each chromosome is made of two identical chromatids joined at the centromere.
• Metaphase: Chromosomes line up along the equator/middle of the cell; spindle fibres attach to the centromeres.
• Anaphase: Chromatids are pulled to opposite poles as spindle fibres shorten; the two chromatids of each chromosome separate.
• Telophase: A new nuclear envelope forms around each set of chromosomes at opposite poles; two genetically identical nuclei are produced.
• Cytokinesis: The cytoplasm divides to produce two genetically identical daughter cells.

Top tip: Always say what happens to the chromosomes at each stage — that is what earns marks. Simply naming the stages without explaining chromosome behaviour will only score partial marks.

Common 6-mark mark scheme structure: 1 mark per stage correctly described (P, M, A, T) + 1 mark for cytokinesis + 1 mark for mentioning identical daughter cells or equal distribution of chromosomes.

Edexcel 1BI0 — Paper 1 (1BI0/1) Notes

On Edexcel Paper 1, mitosis appears in Topic 2: Cells and Control. Edexcel-specific points to note:

• Photomicrograph questions: Edexcel commonly provides an image of cells at different stages of mitosis and asks you to "identify the stage shown" and "explain how you know." Your answer must describe the chromosome arrangement visible — for example, "this is metaphase because the chromosomes are lined up along the equator of the cell."
• Cell cycle proportion questions: Edexcel may give a pie chart or data showing how much time a cell spends in each phase and ask you to "explain why most of the cell cycle is spent in interphase." Your answer should reference DNA replication and cell growth — not just say "interphase is the longest phase."
• "Suggest" for cancer context: Edexcel frequently links mitosis to cancer — e.g., "Suggest why mutations in genes controlling the cell cycle may lead to cancer." Follow the chain: mutation → genes controlling mitosis disrupted → uncontrolled cell division → tumour.
• Stem cell connection: Edexcel sometimes asks about mitosis in the context of stem cells and therapeutic cloning (Topic 2). Be ready to explain how mitosis maintains the same genetic information in daughter cells, making them suitable for transplantation.