The Synthesis and Hydrolysis of ATP (A-level Biology)
The Synthesis and Hydrolysis of ATP
Synthesising ATP
Photophosphorylation and Chemiosmotic Theory
Previously, we saw how ATP was formed in the light-dependent reaction of photosynthesis. We will recap the synthesis of ATP again here:
- ADP and Phosphate are required to form ATP. Two reactants are required to form ATP. These are ADP and an inorganic phosphate (Pi).
- A H+ ion is the catalyst. In this reaction, a H+ ion is required to act as the catalyst for ADP + Pi → ATP. This process is known as non-cyclic photophosphorylation.
Hydrolysing ATP
We also saw how ATP was hydrolysed in the light-independent reaction of photosynthesis, called the Calvin Cycle. We will recap the hydrolysis of ATP again here:
- ATP and reduced NADP are required to reduce GP. In the Calvin cycle, ATP and reduced NADP are used to form triose phosphate from GP.
- GP is reduced to triose phosphate (TP). 2 molecules of GP are reduced to form two molecules of triose phosphate (also 3C). For this reaction to occur, we need H+ ions and energy:
- The H+ ions come from conversion of reduced NADP to NADP.
- The energy comes from the hydrolysis of ATP to ADP and Pi.
- ATP has been hydrolysed. Through this reaction, ATP has been converted back into ADP and an inorganic phosphate. The reduced NADP is converted into NADP.
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