Exam Focus: How to Answer Cancer Questions

Exam Focus: How to Answer Cancer Questions

Most common exam question format (4-6 marks):

"Explain how lifestyle factors increase the risk of cancer."

The required chain of reasoning — you MUST include all four steps:

1. Risk factor: Name a specific lifestyle factor or carcinogen (e.g., UV radiation from sun exposure)
2. DNA mutation: Explain that the carcinogen causes mutations in the DNA of skin cells
3. Uncontrolled division: State that these mutations affect genes controlling the cell cycle, leading to uncontrolled mitosis
4. Tumour formation: Explain that the rapidly dividing cells accumulate to form a tumour

For higher marks, also mention:

• Both lifestyle AND genetic factors can increase risk (examiner keyword: "genetic predisposition")
• The specific genes affected: oncogenes become overactive, tumour suppressor genes are inactivated
• If a malignant tumour forms, cancer cells can spread (metastasis) making treatment harder

Common mistakes that lose marks:

• Saying "carcinogens cause cancer" without explaining the mechanism (DNA mutation step)
• Confusing "benign" and "malignant" — always define both if you use either term
• Forgetting to mention uncontrolled cell division — this is the core biology

Edexcel 1BI0 — Paper 1 (1BI0/1) Notes

On Edexcel Paper 1, cancer and cell cycle control appear in Topic 2: Cells and Control. Edexcel-specific points to note:

• Data interpretation: Edexcel commonly provides statistics about cancer incidence or survival rates as a stimulus, then asks you to "suggest" why a particular lifestyle factor increases risk. Always follow the mechanism: carcinogen → DNA mutation → disrupts cell cycle control genes → uncontrolled mitosis → tumour.
• Treatment questions with context: Edexcel may present a case study about a cancer patient receiving chemotherapy or radiotherapy, then ask you to "explain why the patient experiences side effects on healthy tissue." The answer requires linking the treatment's mechanism to its effects on rapidly dividing normal cells (e.g., gut lining, hair follicles, bone marrow).
• "Suggest" for genetic factors: Edexcel tests genetic predisposition — "Suggest why some people are more likely to develop cancer even without environmental risk factors." Your answer should mention inherited mutations in tumour suppressor genes or oncogenes.
• Edexcel mark scheme language: The phrase "uncontrolled cell division" is the core mark-scheme term. "Uncontrolled mitosis" is also accepted. Do not just write "cells divide too much" — use the precise biological language.