GCSE Biology · AQA 8461 · Topic 4.4
Bioenergetics
Key points
- Photosynthesis is an endothermic reaction that uses light energy to make glucose and oxygen from carbon dioxide and water in chloroplasts.
- Its rate is limited by light intensity, carbon dioxide concentration, temperature and the amount of chlorophyll.
- Glucose is used for respiration and to make starch, cellulose, fats, oils and amino acids.
- Respiration is an exothermic reaction that releases energy in every living cell.
- Aerobic respiration uses oxygen; anaerobic respiration does not, releases less energy and makes lactic acid in muscles or ethanol and CO in yeast.
- Metabolism is the sum of all the reactions in a cell or the body.
Topic notesPremium
Bioenergetics is about how living things capture and release energy. Plants trap light energy in glucose by photosynthesis, and every organism releases energy from glucose by respiration to power life processes.
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