<prompt> Which of the following is a constituent of Cytochrome C reductase?B1B2BiotinPyridoxine  <response>: RIBOFLAVIN VITAMIN B2 Biological Active Forms The biologically active forms, in which riboflavin serves as the prosthetic group as the 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-PO4FAD 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 contains in Warburgs yellow enzymeCytochrome-C-reductaseL-amino acid oxidase SECTION TWO Fp is auto-oxidizable at substrate level by molecular O2 forming H2O2Ref: MN Chatterjea Textbook of Medical Biochemistry, 8th edition, page no: 180 