This exam focus covers Exam Focus within Carbon Cycle for GCSE Biology. Topic 3: Carbon Cycle It is section 9 of 11 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 9 of 11
Practice
15 questions
Recall
20 flashcards
Exam Focus
Frequently ExaminedThe carbon cycle appears regularly on AQA Paper 2, often paired with climate change. Questions frequently ask students to trace carbon through the cycle or explain human impacts. Key patterns include:
- Process questions (2-3 marks): "Name the processes by which carbon is returned to the atmosphere" — list respiration, combustion, decomposition (and fossil fuel burning).
- Diagram questions (3-4 marks): Add missing arrows or labels to a carbon cycle diagram; state which process each arrow represents.
- Human impact questions (4-6 marks): Explain how deforestation or burning fossil fuels increases atmospheric CO2 — always link to specific carbon cycle processes (reduced photosynthesis AND increased combustion for deforestation).
- Carbon sink/source questions (2-3 marks): Distinguish between carbon sinks and sources; explain why an activity converts a sink to a source.
Common mark-losing errors: Saying plants only photosynthesise (they also respire); saying decomposition doesn't produce CO2; forgetting that deforestation reduces photosynthesis as well as increasing combustion; describing peat bogs as releasing CO2 without linking to decomposers gaining access to oxygen.