Leaving Certificate Photosynthesis Practice Test

NAD stands for nicotinamide adenine dinucleotide, a coenzyme that carries electrons during many metabolic redox reactions. The name reflects its structure: two nucleotides joined together, one containing nicotinamide and the other containing adenine, connected by phosphate groups. In its oxidized form NAD+ accepts a hydride to become NADH, functioning as an electron shuttle in pathways like glycolysis and respiration. The other options mix up parts of the name or refer to something unrelated (DNA components, using nicotinic acid instead of nicotinamide, or an untrue compound), so nicotinamide adenine dinucleotide is the correct form.