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Integrated SequencePhysics Chemistry Organic Biology

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Conjugated π Systems and Aromaticity

Nucleic Acids

Bioenergetics and Cellular Respiration

NADH and FADH2 are nucleotide derivatives. They are the major electron carriers in the oxidation of nutrient molecules. Their role is to transfer reduction potential. NAD+ is synthesized from vitamin B3 (niacin). We say that NADH is an 'electron carrier', but what happens when NAD+ is reduced is that it receives the donation of a hydride from the mebolite involved in glycolysis or the citric acid cycle. The type of enzyme involved in the hydride transfer is a dehydrogenase.

An interesting aspect of the hydride (electron) transfer is that the nicotinamide ring in NAD+ is aromatic, while in NADH it is not. The aromatic stability of NAD+ is key to understanding why NADH donates its electron so easily (either in fermenatation in anaerobic respiration or to the electron transport system in aerobic metabolism).








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