AP BIOLOGY

Detailed explanation-1: -NAD+ is used as an electron acceptor during glycolysis, whereas NADH is used by mitochondrial complex I to drive the mitochondrial electron transport chain (ETC).

Detailed explanation-2: -Nicotinamide adenine dinucleotide (NAD+) is an important molecule in glycolysis. It is a cofactor which regulates metabolism through its electron transport function in the redox reaction in glycolysis and the TCA cycle, In glycolysis, NAD+ reduces forming NADH and H+. If NAD+ is absent, glycolysis cannot continue.

Detailed explanation-3: -NAD is one of the main electron carriers in redox reactions, with a unique ability to function as both a donor and an acceptor. To perform its role as an electron carrier, NAD reverts back and forth between two forms, NAD+ and NADH. NAD+ accepts electrons from food molecules, transforming it into NADH.

Detailed explanation-4: -Both glycolysis and the citric acid cycle require NAD+ to accept electrons during their chemical reactions. In order for the cell to continue to generate any ATP, NADH must be converted back to NAD+ for use as an electron carrier.

Detailed explanation-5: -NAD+ is mostly used in catabolic pathways, such as glycolysis, that break down energy molecules to produce ATP. The ratio of NAD+ to NADH is kept very high in the cell, keeping it readily available to act as an oxidizing agent. NADH is used in the electron transport chain to provide energetic electrons.