Limiting Factors Flashcards
All 8 cards in this deck
What is a limiting factor of photosynthesis?
The factor in shortest supply that is holding back (limiting) the rate of photosynthesis.
Name the three limiting factors of photosynthesis.
Light intensity, carbon dioxide concentration and temperature.
What is the effect of increasing carbon dioxide concentration on the rate of photosynthesis?
The rate increases, until carbon dioxide is no longer the limiting factor and the rate levels off.
Why does the rate of photosynthesis fall at temperatures above the optimum?
The enzymes controlling photosynthesis become denatured (their active sites change shape).
Why does the rate of photosynthesis increase as temperature rises up to the optimum?
More collisions occur, so enzymes catalyse more reactions (more enzyme–substrate complexes form).
On a multi-line graph of rate of photosynthesis against light intensity, what does a higher plateau for one line show?
That another factor (e.g. temperature or concentration) was increased, so it is less limiting.
True or false? Raising the temperature always increases the rate of photosynthesis.
False. Above the optimum the enzymes denature and the rate falls.
True or false? Only one factor can limit the rate of photosynthesis at any one time.
True. The rate is limited by whichever factor is in shortest supply at that moment.