MDCAT Biology MCQ #451

During active photosynthesis, a pH gradient is established across the thylakoid membrane. Which comparison of the compartments is correct?

MDCAT Biology MCQ #451

  1. Question 1

    Q1. During active photosynthesis, a pH gradient is established across the thylakoid membrane. Which comparison of the compartments is correct?

    • A) The thylakoid lumen has a lower pH than the stroma
    • B) The stroma has a higher concentration of H+ ions
    • C) The pH of both compartments remains neutral at 7.0
    • D) The intermembrane space is less acidic than the matrix

    Answer: The thylakoid lumen has a lower pH than the stroma

    Explanation: The thylakoid lumen becomes acidic (low pH) due to proton accumulation, while the stroma becomes basic (high pH).