STRUCTURE OF THE ELECTRON TRANSPORT CHAIN
The presence of a series of electron transport molecules is a key component for the production of energy in the form of ATP in both aerobic respiration and the light-dependent reactions of photosynthesis. These electron transport chains are embedded in the cristae of mitochondria and in the thylakoid membranes of chloroplasts.

Similar coenzymes are associated with both electron transport chains. Cellular respiration involves two coenzymes: NAD⁺ (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide). In photosynthesis, a coenzyme very similar to NAD⁺, NADP⁺ (nicotinamide adenine dinucleotide phosphate), serves the same function.