Practice question

Polyacrylamide polymerization can be initiated chemically via APS-TEMED or photochemically via riboflavin. Riboflavin (vitamin B2) undergoes photolysis under visible or UV light to generate free radicals that initiate acrylamide polymerization, particularly when combined with TEMED as co-catalyst. This light-controlled method allows slower, more uniform gelation, useful when rapid chemical polymerization is undesirable and for preparing low-percentage gels. Ethidium bromide is an intercalating fluorescent dye, TEMED alone is a chemical catalyst not photochemical, and TAE is an electrophoresis buffer. Hence riboflavin functions as classic photochemical initiator for gel formation.