Interdependence of Photosynthetic Reactions
- The light dependent reaction and light independent reaction are interdependent
- This means that one cannot occur without the other
- Products from the light dependent reaction (reduced NADP and ATP) are directly used in the Calvin cycle to produce carbohydrates
- This means that in low light intensity, the products are produced at a slower rate which limits the conversion of GP to TP
- Once the reduced NADP has been oxidised in the Calvin cycle, NADP is returned to the light dependent stage to accept electrons at the end of the electron transport chain
- In high light intensity, the light dependent reactions occur more quickly, providing more reduced NADP and ATP to drive the Calvin cycle
- However, if NADP is not returned to the light dependent stage quickly enough, then the process will be restricted
- Products from the light dependent reaction (reduced NADP and ATP) are directly used in the Calvin cycle to produce carbohydrates
- Carbon dioxide, in the form of hydrogen carbonate ions (HCO3-), accepts protons from photosystem II when water is split during photolysis
- Hydrogen carbonate also plays an important role in the functioning of the electron transport chain
- A lack of carbon dioxide (and thus hydrogen carbonate) will not only prevent carbon fixation from occurring but also prevent photosystem II from functioning