<prompt> Which of the following vitamin is used in the electron transpo chain?ThiamineRiboflavinNicotinic acidVitamin B12  <response>: The biologically active forms, in which riboflavin serves as the prosthetic group as coenzyme of a number of enzymes are the phosphorylated derivatives. Two main derivatives are: FMN Flavin mononucleotide: In this the phosphoric acid is attached to ribityl alcoholic group in position 5. Flavin-Ribityl-PO4 FAD Flavin adenine nucleotide: It may be linked to an adenine nucleotide through a pyrophosphate linkage to form FAD. Flavin-ribityl-P-P-ribose-Adenine Thus, FMN and FAD are two coenzymes of this vitamin. FMN constitutes in Warburgs yellow enzyme Cytochrome-C-reductaseRef: MN Chatterjea Textbook of Medical Biochemistry, 8th edition, page no: 180 