MDCAT Biology MCQ #347

Protons accumulate in the thylakoid lumen during light-dependent reactions. Which process, besides photolysis, is directly responsible for building this electrochemical gradient?

MDCAT Biology MCQ #347

  1. Question 1

    Q1. Protons accumulate in the thylakoid lumen during light-dependent reactions. Which process, besides photolysis, is directly responsible for building this electrochemical gradient?

    • A) ATP synthase activity
    • B) Cytochrome b6f complex pumping
    • C) NADP+ reductase activity
    • D) RuBP carboxylase activity

    Answer: Cytochrome b6f complex pumping

    Explanation: The cytochrome b6f complex pumps protons into the lumen. ATP synthase is wrong because it facilitates proton flow back into the stroma.