Photosynthetic Reaction (AQA GCSE Combined Science: Trilogy: Biology): Revision Note

Photosynthesis

• Plants 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

 Word equation for photosynthesis

$CarbonDioxide+Water\underset{Chlorophyll}{\overset{Light}{\to }}Glu\cos e+Oxygen$

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 Balanced symbol equation for photosynthesis

$6C{O}_2+6H_{2}O\underset{Chlorophyll}{\overset{Light}{\to }}{C}_6{H}_{12}{O}_6+6O_2$

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Sources of reactants and uses of products in photosynthesis

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