What is another name for a basic or positively charged dye?

• A. Cationic dye
• B. Anionic dye
• C. Neutral dye
• D. Zwitterionic dye

Answer: (A)

Dyes categorized as basic carry a positive charge, so they are called cationic dyes. That positive charge comes from groups like ammonium in the dye molecule, which makes the dye attracted to negatively charged tissue components (such as DNA, RNA, and acidic proteins). This electrostatic attraction is why basic/cationic dyes stain these structures well, generating basophilic features in cells and nuclei. The term “cationic dye” is simply another way to describe a basic or positively charged dye.

Anionic dyes are negatively charged and target positively charged tissue components, neutral dyes have no net charge, and zwitterionic dyes contain both positive and negative regions but aren’t classified as basic dyes.