So, as I mentioned in the beginning, the mitochondrion actually consists of two different types of membranes. We have the outer membrane and the inner membrane. So the innermost compartment of the mitochondrion is known as the mitochondrial matrix. And the space between the two membranes is called the intermembrane space. And this is found entirely in the inner mitochondrial membrane. Now, there are several important differences between these two membranes.