Question

1. If the inner mitochondrial membrane were rendered as permeable as the outer membrane, how would that affect oxidative phosphorylation? Which specific processes would stop and which remain? 2. Present two types of benefits derived from separating the reactions of glycolysis in the cytosol from those that occur during the citric acid cycle in the mitochondrion

Answer 1

1. During oxidative phosphorylation, the electrons are transferred through a series of electron carriers and the energy released from this process is used to pump protons from the matrix of mitochondria to the intermembrane space. This creates an electrochemical gradient across the inner mitochondrial membrane, which is nearly impermeable to small ions and protons. It prevents the reentry of protons to the matrix and the protons enter only through the ATP synthase which use this electrochemical gradient to drive synthesis of ATP from ADP and P_i.

However if the inner mitochondrial membrane is rendered freely permeable to ions, then the protons (accumulated in the intermembrane space) will leak back to the matrix, thereby dissipating the electrochemical gradient and hence uncoupling ATP synthesis from electron transport. This will lead to no net synthesis of ATP and ATP synthesis will be halted however there would be no effect on the electron transport chain.