2.19 Understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis

Concentration of CO₂ (carbon dioxide)

If there is a higher concentration of CO₂, the plant will photosynthesise more until a point where the amount of CO₂ outweighs the rest that is needed for this. For example, if you put a plant in a room with a high concentration of CO₂, it would photosynthesise more, but if you continued to increase the concentration, it would need more sunlight, or water, etc. to be able to continue increasing the rate at which is photosynthesizes. If the concentration is too low, the rate will decrease.

Light intensity

If the light / sunlight is more intense, the rate of photosynthesis will also increase. However, if the light is too bright, it might burn the plant’s leaves or cause it to overheat, in which case its enzymes would denature and the rate would go down :( . If the light is too dim, the rate of photosynthesis will decrease as it will not have enough light energy to transfer into chemical energy.

Temperature

If the plant is at optimum temperature, its rate of photosynthesis will be the highest. This is because the enzymes, that are biological catalysts and therefore speed up the plant’s metabolic reactions, will be working at their best. If the temperature is too high, the plant could burn, or its enzymes will denature, bringing down the rate of photosynthesis. Until that point, the higher the temperature, the higher the rate, as it has more energy from the heat .

Figure 1