Solution

Mitochondria are chiefly responsible for converting the chemical energy in macromolecules, like glucose, into molecules of ATP that can be used by the cell for energy. The ability of a mitochondrion to convert glucose and ADP, adenosine triphosphate, into ATP is intricately connected to the structure of the mitochondrial membranes. In a process called glycolysis, which occurs in the cytoplasm just outside the mitochondrion, electrons are stripped from glucose and passed through the outer mitochondrial membrane into the intermembrane space. Here, the electrons are passed to a series of special proteins embedded in the IMM. As the electrons move from one membrane protein to the next, energy is released and protons (hydrogen ions, or H+) in the matrix are pumped across the IMM and into the intermembrane space. Fairly quickly, a large number of protons accumulate in the intermembrane space and like water behind a dam, exert great pressure on the IMM. Thus, option C is correct. In mitochondria, protons do not accumulate in the outer membrane, inner membrane or matrix. Thus, other options are wrong.