Question

Which one of the following statements about photophosphorylation is false?

A) It can be uncoupled from electron flow by agents that dissipate the proton gradient.
B)The difference in pH between the luminal and stromal side of the thylakoid membrane is 3 pH units.
C)The luminal side of the thylakoid membrane has a higher pH than the stromal side.
D) The number of ATPs formed per oxygen molecule is about three.
E)The reaction centers, electron carriers, and ATP-forming enzymes are located in the thylakoid membrane.

Answer 1

C)The luminal side of the thylakoid membrane has a higher pH than the stromal side.

Step-by-step explanation:

During the photophosphorylation, the electrons move through many electron carriers which allow the transport of hydrogen ions in the luminal side against the concentration gradient. This allows the increase in the Hydrogen ion concentration to the luminal side of thylakoid membrane and reduction in the hydrogen ion concentration of the stromal side.

Therefore due to the increased concentration of H⁺ ions in lumen during the photophosphorylation, the lumen has a lower pH than the stroma. During photophosphorylation, the pH of lumen decreases up to 4 and the pH of stroma increases up to 8. So the false option is C.