Title: Factors affecting photosynthesis - Photosynthesis - OCR Gateway - GCSE Combined Science Revision - OCR Gateway - BBC Bitesize
Headings: Factors affecting photosynthesis
Photosynthesis
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Factors affecting photosynthesis
Light intensity
Carbon dioxide concentration
Temperature
Chlorophyll
The compensation point

Content: the rate of oxygen output
the rate of carbon dioxide uptake
the rate of carbohydrate production
These are not perfect methods as the plant will also be respiring, which will use up some oxygen and carbohydrate and increase carbon dioxide output. Several factors can affect the rate of photosynthesis: light intensity
carbon dioxide concentration
temperature
The amount of chlorophyll also affects the rate of photosynthesis: plants in lighting conditions unfavourable for photosynthesis may synthesise more chlorophyll, to absorb the light required
the effects of some plant diseases affect the amount of chlorophyll, and therefore the ability of a plant to photosynthesise
Light intensity
Without enough light, a plant cannot photosynthesise very quickly - even if there is plenty of water and carbon dioxide and a suitable temperature. Increasing the light intensity increases the rate of photosynthesis , until some other factor - a limiting factor - becomes in short supply. previous
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At low light intensities the increase in the rate of photosynthesis is linear
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At some point a factor becomes limiting. For instance, if carbon dioxide becomes the limiting factor the supply of carbon dioxide is not sufficient to keep pace with the increasing rate of reaction. previous
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Any additional increase in light intensity will not increase the rate of reaction any further. At very high light intensities, photosynthesis is slowed and then inhibited, but these light intensities do not occur in nature. Carbon dioxide concentration
Carbon dioxide - with water - is one of the reactants in photosynthesis.