Final answer:
NAD and FAD are the main coenzymes that carry electrons in catabolic pathways.
Step-by-step explanation:
The main coenzymes that carry electrons in catabolic pathways are nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD). NAD+ is the oxidized form of the molecule, while NADH is the reduced form after accepting two electrons and a proton. FAD is another important coenzyme that can be easily reduced or oxidized to FADH2.