- Mitochondria (plenty of redox reactions (aka electron transfers))
- Fatty acid oxidation (β-oxidation), acetyl-CoA production, TCA cycle, oxidative phosphorylation, ketogenesis.
- Cytoplasm (processes that build larger molecules)
- Glycolysis, HMP shunt, and synthesis of cholesterol (SER), proteins (ribosomes, RER), fatty acids, and nucleotides.
- Both
- Heme synthesis, Catabolism of amino acids, gluconeogenesis. Hugs take two (both).