Biosynthetic cost of a mitochondrion

Using the estimation that a rat liver mitochondrion has 3.15e-10mg protein, we can find the mass of an 'average' protein, following Phillips, Rob, et al. Physical biology of the cell. Garland Science, 2012, as 5e-20g.

This implies a mitochondrion consists of 7e6 proteins. If each protein consists of 300 amino acids, and each amino acid requires 5.2 ATP to synthesize and append the molecule to a peptide chain, then this means that a mitochondrion requires 7e6 x 300 x 5.2 = 1.09e10 ATPs.