Mitochondria Structure and Function

Morphology: No. of mitochondria depends on cell type and functional state of cell
Size: 0.5-2.0 µm

Structure:

double membrane organelle
Outer membrane with porin proteins (transport proteins) , permeable
Inner membrane with infoldings called cristae , less permeable, presence of cardiolipin
Mitochondrial matrix: proteins 65-70%, lipids 25-30%, 0.5% RNA and circular DNA molecule
Microscopic observation: Janus Green stain-stains living mitochondria greenish blue.

Function:

Inner membrane: site of oxidative phosphorylation and electron transport and associated ATP production.
Central matrix: site of citric acid cycle and fatty acid break down and mt DNA codes some mt proteins.

Histochemical/ cytochemical markers:

Similarity between mitochondria and prokaryotes

(that supports Endosymbiont theory)

The bacterial plasma membrane resembles the inner mitochondrial membrane in many aspects. Bacterial plasma membrane has infolding called mesosomes.
Circular ds DNA
Not covered by a membrane
Not associated with histone proteins
Generally lack introns
Small 70 S ribosomes
Protein synthesis initiated by formyl methionyl tRNA (f-met tRNA) and in both mitochondria and bacteria protein synthesis can be inhibited by the same inhibitor chloramphenicol
Replication, transcription and translation similar to bacteria.
And high degree of relatedness between mt genes and bacterial genes