Mitochondria are enclosed by a double-membrane system made up of an inner and an outer membrane. The space between these two membranes is called (surprise!) the intermembrane space. The inner membrane encloses the interior of the mitochondrion, which is known as the mitochondrial matrix.The inner membrane also forms a large number of folds, called cristae, that extend into the matrix.See Fig.he space between these two membranes is called (surprise!) the intermembrane space. The inner membrane encloses the interior of the mitochondrion, which is known as the mitochondrial matrix. The inner membrane also forms a large number of folds, called cristae, that extend into the matrix. See Fig.
1. relative atomic mass - (chemistry) the mass of an atom of a chemical element expressed in atomic mass units. atomic mass, atomic weight. mass-the property of a body that causes it to have weight in a gravitational field.
the total mass of an atom, numerically equivalent to the mass in grams of 1 mole of the atom. (For element with more than one isotope, the atomic mass is the average mass of the naturally occurring isotopes, weighted by their abundance.) Isotope one of the several atomic forms of the element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass.