Explain how carbon in carbon dioxide gas in the atmosphere becomes part of the carbon compounds in the body of an animal.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Carbon dioxide in the atmosphere is taken up by green plants during photosynthesis. The CO₂ is converted into organic carbon‑containing compounds such as glucose. Animals then eat the plants (or other organisms that have eaten the plants), transferring the carbon compounds into their bodies. The animal digests the food, breaking down the organic molecules and uses the carbon to build its own biomass and other carbon‑containing compounds.
Examiner tips
- Use the exact sequence: absorption by plants → photosynthesis → organic compounds → animal consumption → digestion and synthesis.
- Mention the key terms: photosynthesis, glucose, digestion, synthesis.
- Show the transfer of carbon from CO₂ to animal biomass.
Mark scheme (4 marks)
- Carbon dioxide is absorbed / taken in by producers / green plants during photosynthesis
- Carbon dioxide is converted into organic / carbon-containing compounds (e.g. glucose / sugars / carbohydrates) in the plant
- Animals eat / feed on producers (or other organisms that have eaten producers) — i.e. feeding / consumption transfers carbon compounds
- The organic compounds from food are digested / broken down and used to build / synthesise the animal's own carbon-containing compounds / biomass
Related
- All Pearson Edexcel International GCSE Biology (4BI1) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →