The splicing of Group I introns. This occurs by a ribozymic mechanism where the intron sequence forms a distinct 3D structure, characteristic of Group I introns and involved in determining the locations of the splice sites (there do not appear to be consensus splice site sequences) as well as having a role in catalyzing the splicing reactions, though protein factors are also required in vivo. Splicing occurs by a series of two transesterification reactions, generally with exogenous guanosine as the initiating nucleophile. The intron is excised as a linear piece (though it may subsequently circularize).

The chemical reactions and pathways resulting in the breakdown of RNA transcribed from the mitochondrial genome and occurring in the mitochondrion.

The process in which new strands of DNA are synthesized in the mitochondrion.

A mitochondrial protein complex with 3' to 5' exoribonuclease activity that participates in intron-independent turnover and processing of mitochondrial transcripts. In humans, the mitochondrial degradosome is a pentameric complex, and in yeast it exists as a heterodimer.

A semiautonomous, self replicating organelle that occurs in varying numbers, shapes, and sizes in the cytoplasm of virtually all eukaryotic cells. It is notably the site of tissue respiration.