<prompt> Number of vitamins required in citric acid cycle is:2345  <response>: Four of the B vitamins are essential in the citric acid cycle and hence energy-yielding metabolism: 1 riboflavin, in the form of flavin adenine dinucleotide FAD, a cofactor for succinate dehydrogenase; 2 niacin, in the form of nicotinamide adenine dinucleotide NAD, the electron acceptor for isocitrate dehydrogenase, a-ketoglutarate dehydrogenase, and malate dehydrogenase; 3 thiamin vitamin B1, as thiamin diphosphate, the coenzyme for decarboxylation in the a-ketoglutarate dehydrogenase reaction; and 4 pantothenic acid, as pa of coenzyme A, the cofactor attached to active carboxylic acid residues such as acetyl-CoA and succinyl-CoA Ref: Harper 28th edition, chapter 17. 