Final answer:
In a Gram stain procedure, Gram's iodine acts as a mordant to help set or stabilize stains or dyes. It forms a complex with the crystal violet dye, allowing it to stay contained in the cell walls.
Step-by-step explanation:
In a Gram stain procedure, Gram's iodine acts as a mordant. A mordant is a substance that helps set or stabilize stains or dyes. Gram's iodine forms a complex with the crystal violet dye, allowing it to stay contained in the thick layers of peptidoglycan in the cell walls. This helps differentiate between Gram-positive and Gram-negative bacteria.