Question Constellation Sign up for free AQA · GCSE · Biology · Higher
Photosynthesis Limiting Factors
Light, carbon dioxide and temperature are limiting factors of photosynthesis. Figure 7 shows how the rate of photosynthesis is affected by light, carbon dioxide and temperature.
At point A on Figure 7, light is a limiting factor. What is meant by a ‘limiting factor’?
Write your answer first. You can study the marking guidance whenever you need it.
Study the marking See what earns credit and compare it with a full-mark answer.
Marking points
- 1 Defines a limiting factor as one whose increase would increase the rate, or one preventing a higher/maximum rate.
Full-mark answer
It is a factor that is stopping the rate from increasing; if more of that factor were supplied, the rate would increase.
Why this answer loses marks
A factor that slows photosynthesis.
This is too vague; define it through the increase in rate that would follow if the factor increased.