Answer:
D Flow of protons across an electrochemical gradient
Explanation:
The chloroplast adenosine triphosphate (ATP) synthase uses the electrochemical proton gradient generated by photosynthesis to produce ATP, the energy currency of all cells. Protons conducted through the membrane-embedded Fo motor drive ATP synthesis in the F1 head by rotary catalysis.
In chloroplasts, photosynthetic electron transport generates a proton gradient across the thylakoid membrane which then drives ATP synthesis via ATP synthase.
The light-induced electron transfer in photosynthesis drives protons into the thylakoid lumen. The excess protons flow out of the lumen through ATP synthase to generate ATP in the stroma.
Majority of ATP is produced by OXIDATION PHOSPHORYLATION. The generation of ATP by oxidation phosphorylation differs from the way ATP is produced during glycolysis.
Electrons are passed from one member of the transport chain to another in a series of redox reactions. Energy released in these reactions is captured as a proton gradient, which is then used to make ATP in a process called chemiosmosis.
