Limiting factors in photosynthesis Flashcards
What are the optimum conditions for photosynthesis?
1) High light intensity of certain wave lengths (red+Blue)
2) Temperature around 25 degrees Celsius
3) Carbon dioxide at 0.4%
How does high temperature affect light INDEPENDENT reaction?
High temperatures only affect light independent reaction in one way:
- Membranes of the chloroplast could be damaged causing enzymes that are used in the calvin cycle to be released into the cell. This reduced the rate of light INDEPENDENT reactions.
what are the 3 ways high temperature can affect light DEPENDENT reactions?
At high temperatures:
1) Stomata close to avoid losing too much water, this causes the rate of photosynthesis to decrease as less CO2 enters the leaf.
2) Thylakoid membrane may be damaged, which could reduce the rate of the light DEPENDENT stage reaction, by reducing the number of sites available for electron transfer.
3) Chlorophyll could be damaged, which can reduce the amount of light that is absorbed by photosynthetic pigments, this would reduce the rate of light DEPENDENT reactions.
How does light intensity affect Calvin cylce?
- In low light intensity less reduced NADP and ATP is produced
- Conversion of GP to TP and RuBP will be slow, but level of GP will rise as it is still being made and levels of TP and RuBP will fall.
How does temperature affect calvin cycle?
- calvin cycle is catalysed by enzymes
- At low temps all reactions will be slower as enzymes work more slowly.
- This means levels of GP TP and RuBP will all fall.
How does Co2 concentration affect calvin cycle?
At lower concentration of CO2:
-conversion of RuBP to GP is slow, as there is less Co2 to combine with RuBP to make GP.
- So level of RuBP will rise as it is still being made and levels of GP and TP will fall.
At low light intensity what is still being made in the calvin cycle
GP
levels of TP and RuBP fall
At low Co2 what is still being made in the calvin cycle?
RuBP
levels of GP and Tp fall
