Factors Affecting Photosynthesis
Light, CO₂ and temperature limit photosynthesis.
About this topic
The rate of photosynthesis is limited by the factor in shortest supply: light intensity, carbon dioxide concentration and temperature. Increasing light raises the rate until another factor limits it. Temperature affects enzymes, increasing the rate to an optimum around 30–40 °C, then denaturing them. Chlorophyll amount also matters.
Greenhouses boost yields by controlling light, CO₂ and temperature. Graphs show plateaus where a different factor has become limiting. Oxygen bubbles from pondweed can be counted to measure the rate.
On a graph of rate against light, the line climbs and then flattens; at that point, carbon dioxide or temperature is limiting. Greenhouse growers raise carbon dioxide levels, add lighting and control warmth to raise yields. Above about 40 degrees C, enzymes denature and the rate drops sharply.
Counting bubbles from pondweed at different distances from a lamp is a classic experiment; since light follows the inverse square law, doubling the distance cuts the intensity to a quarter. Chlorophyll content also matters. Students often think that more of any factor always increases the rate; a limiting factor model shows only the scarcest one controls the rate at a given time. Another error is explaining plateaus as the plant stopping working.
Key ideas
- The scarcest factor is limiting
- Plateau when saturated
- Enzymes denature when hot
Quick check
Use cases: where Factors Affecting Photosynthesis helps
- Homework: review the key idea behind Factors Affecting Photosynthesis before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Factors Affecting Photosynthesis without notes.
- Visual learning: play with the interactive lab to see how Factors Affecting Photosynthesis changes when you adjust its inputs.
- Teaching a friend: explain Factors Affecting Photosynthesis in your own words, then compare your version with the key ideas.
Biology underpins medicine, farming, conservation and biotechnology.
Frequently asked questions
What is Factors Affecting Photosynthesis?
Light, CO₂ and temperature limit photosynthesis.
What will I learn in Factors Affecting Photosynthesis?
The scarcest factor is limiting. Plateau when saturated. Enzymes denature when hot.
Is Factors Affecting Photosynthesis part of Biology?
Yes. It is one of 150 Biology topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Factors Affecting Photosynthesis lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Factors Affecting Photosynthesis?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
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