AQA GCSE Biology

Revision Notes

4.1.1 Photosynthetic Reaction


  • Plants are autotrophs – this means that they can make their own food using light, water and carbon dioxide
  • This is why they are called producers in food chains
  • Photosynthesis is an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light
    • The leaves of the plant are where most photosynthesis takes place, in specialised mesophyll cells which are packed with chloroplasts containing chlorophyll to absorb as much light energy as possible
  • The sugars produced by photosynthesis are used to make all the substances a plant needs, as well as being used in respiration to release energy
  • These reactions can be summarised into a simple equation


Photosynthesis word equation, IGCSE & GCSE Biology revision notes

Word equation for photosynthesis


Balanced chemical equation for photosynthesis, IGCSE & GCSE Biology revision notes

Balanced symbol equation for photosynthesis

  • The reactants for photosynthesis are obtained by a plant as follows:


How plants get the materials they need, IGCSE & GCSE Biology revision notes

Plants obtain the materials they need for photosynthesis from the environment

Exam Tip

Photosynthesis is essential for the majority of all food chains on Earth, so learning the equation above is essential!

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