Question

In the process of photosynthesis, where is ATP primarily formed in the "Z-scheme" of oxygenic photosynthesis?

A) Photosystem I
B) Photosystem II
C) Cytochrome b6f complex
D) Calvin cycle

Answer 1

ATP is formed at the cytochrome b6f complex during the Z-scheme of oxygenic photosynthesis, where an electrochemical gradient drives the production of ATP via chemiosmosis.

Step-by-step explanation:

In the process of photosynthesis, ATP is primarily formed in the Z-scheme of oxygenic photosynthesis at the cytochrome b6f complex. After absorbing light energy, photosystem II (PSII) initiates the process by exciting electrons, which are then passed through an electron transport chain. The chain includes the cytochrome b6f complex, where hydrogen ions are pumped into the thylakoid space creating an electrochemical gradient. These ions flow back into the stroma through ATP synthase during chemiosmosis, leading to the synthesis of ATP. This ATP, alongside NADPH generated by photosystem I (PSI), is then utilized in the Calvin cycle to produce glucose from CO2.