The right answer is D) Increased surface area, Increased output.
Very numerous in young cells and / or very active, which require a lot of energy (like spermatozoa), mitochondria are organelles because they constitute functional units of the cell: they are the "energy factories". Ubiquitous in any animal or plant cell, mitochondria exist even in anucleate blood thrombocytes.
In the electron microscope, the mitochondria appear to consist of a system of membranes similar to the plasmalemma, delimiting two distinct spaces:
* The intermembrane space is located between the outer membrane of the mitochondria and the inner membrane, which projects several folds towards the center of the organelle in order to increase its intermembrane surface and thus to increase its profitability in energy production, thanks to the electron transport chain present in the membrane.
* The matrix is the central fluid of the mitochondria, circumscribed by the internal membrane. The folds of the inner membrane are mitochondrial ridges on the surface of which are attached very many tiny spherical structures bathed in the matrix.
