Answer: Here you go!
NADH: NADH is the abbreviation for the naturally occurring biological substance, nicotinamide adenine dinucleotide hydride. ... Often referred to as coenzyme 1, NADH is the body's top-ranked coenzyme, a facilitator of numerous biological reactions.
FADH: Flavin adenine dinucleotide, or FADH2, is a redox cofactor that is created during the Krebs cycle and utilized during the last part of respiration, the electron transport chain. Nicotinamide adenine dinucleotide, or NADH, is a similar compound used more actively in the electron transport chain as well.
WHY ARE THEY IMPORTANT??
ATP production is an important part of cellular respiration (the process of generating energy from food) and both NADH and FADH2 that are involved in this process help in making more ATP. ... NADH and FADH2 that act as electron carriers give away their electrons to the electron transport chain.