It depends on which type of respiration you are talking about...
Respiration is a process by which a cell acquires energy by oxidation of certain compounds.PRESENCE OF OXYGEN IS NOT MANDATORY FOR OXIDATION.
Respiration is mainly of two types:
In aerobic respiration, the cell uses oxygen to oxidise respiratory substrate, mainly carbohydrate .It is completed in Three steps:
Oxidation of pyruvic acid
But in aerobic prokaryotes, both these processes occur in cytoplasm.
In anaerobic respiration, cells oxidise compounds without the use of oxygen. Only glycolysis occurs in this type of respiration which is a 10 step process
These biochemical reactions are catalysed by various enzymes, coenzymes and cofactors.