-
ATP biosynthesis takes place utilizing the H+ gradient in mitochondria and chloroplasts. Identify the correct sites of H+ gradient formation.
-
- Across the outer membrane of mitochondria and across the inner membrane of chloroplast
- Across the inner membrane of mitochondria and across the thylakoid membrane of chloroplast
- Within the matrix of mitochondria and across the inner membrane of chloroplast
- Within the matrix of mitochondria and within the stroma of chloroplast
Correct Option: B
During chemiosmosis, the free energy from the series of reactions that make up the electron transport chain is used to pump hydrogen hydrogenions across the membrane, establishing an electrochemical gradient. Hydrogen ions in the matrix space can only pass through the inner mitochondrial membrane through a membrane protein called ATP synthase.
ATP synthesis in chloroplasts is very similar to that in mitochondria: Electron transport is coupled to the formation of a proton (H+) gradient across a membrane. The energy in this proton gradient is then used to power ATP synthesis. Two types of processes that contribute to the formation of the proton gradient are:
(a) processes that release H+ from compounds that contain hydrogen, and
(b) processes that transport H+ across the thylakoid membrane.
