Correct option is C
The mitochondria are responsible for ATP production through oxidative phosphorylation. The inner mitochondrial membrane is impermeable to protons, which helps to create a proton gradient. This proton gradient is established by the electron transport chain, where protons (H⁺) are pumped from the mitochondrial matrix into the intermembrane space. As a result, the intermembrane space has a high concentration of protons, which is key for driving ATP synthesis through ATP synthase, which works by utilizing the flow of protons back into the matrix.
Information Booster:
The outer membrane of mitochondria is permeable to small molecules, including protons, but it does not contribute to the proton gradient.
The inner membrane is specialized in establishing and maintaining the proton gradient, which is critical for ATP production.
The intermembrane space has a high concentration of protons compared to the matrix, creating the proton gradient that drives ATP synthesis.
The matrix is the site of the citric acid cycle (Krebs cycle) and contains enzymes for ATP production, but it has a lower proton concentration compared to the intermembrane space.
The proton gradient created across the inner mitochondrial membrane is essential for the function of ATP synthase, which produces ATP.
Additional Knowledge:
The outer membrane is permeable to protons (option 1) is incorrect because while the outer membrane is permeable to ions and molecules, it does not contribute to the proton gradient that is used for ATP production.
The inner membrane is not permeable to protons (option 2) is true in the sense that the inner membrane prevents free movement of protons, which is essential for creating a proton gradient, but this is not the focus of the question.
The matrix has the highest concentration of protons (option 4) is incorrect because the matrix actually has a low concentration of protons, while the intermembrane space has a high concentration.
