Conversation so far:
where are the proteins of the electron transport chain embedded
The electron transport chain is embedded in the inner membrane of the mitochondria. It consists of four large protein complexes, and two smaller mobile carrier proteins.
what type of dna does the mitochondrium contain
The mitochondrion has its own independent genome that shows substantial similarity to bacterial genomes.

Question: why
Self-contained rewrite: why does the mitochondrion show substantial similarity to bacterial genomes