Most mitochondrial proteins are synthesized by ribosomes in the cytoplasm, or cytosol, of the cell.

Proteins destined for the mitochondria are identified as such by markers known as signal sequences.

Specialized proteins called chaperones bind to the protein to prevent premature folding and aid in transport to the mitochondria.

Chaperones use the energy from ATP hydrolosis to keep the precursor protein unfolded.

The protein is then guided to the mitochondrial outer membrane.

Special receptors embedded in the outer membrane recognize the protein's signal sequence.

The protein is then transported through pores in the mitochondrial inner and outer membranes. These pores are associated with the receptors and together are known as a protein translocator complex.