Riboflavin is needed for the formation of flavin mononucleotide (FMN, seen in Complex I of the ETS) and flavin adenine dinucleotide (FAD, from Step 6 of the Krebs). Below is a diagram that shows their structures.
Riboflavin is light-sensitive! That's why you won't see milk in a clear bottle or container.
Good sources: Milk, eggs, liver, green leafy veggies, and whole & enriched grains.
DRI: 0.9-1.3 mg per day
Functions: The 2 co-enzymes discussed above (FMN and FAD).
Deficiencies: Dermatitis, glossitis, corneal vascularization
Toxicity: None known.