Which of the following components is a mordant in the Gram staining process?

In the Gram staining process, the mordant plays a crucial role in the stabilization of the dye within the cell wall of the bacteria. Iodine acts as a mordant because it forms a complex with crystal violet, the primary stain, which enhances the retention of this dye in Gram-positive bacteria. This complex makes it more difficult for the dye to be washed out during the decolorization step of the staining process. As a result, when alcohol or acetone is applied, the thick peptidoglycan layer of Gram-positive bacteria retains the violet dye much better than that of Gram-negative bacteria, which becomes colorless at this stage. Thus, the role of the mordant, in this case, iodine, is essential for the differentiation between the two types of bacteria based on their cell wall structure, ultimately leading to a more definitive and interpretable Gram stain result.