Primary stain

Definition

A primary stain is the first dye applied during a staining procedure to impart color to all cells or structures in a sample. It is crucial for differentiating between various types of microorganisms.

5 Must Know Facts For Your Next Test

1. The primary stain in Gram staining is crystal violet, which colors all bacterial cells purple initially.
2. Primary stains are followed by mordants and counterstains to enhance differentiation of cell types.
3. In acid-fast staining, carbol fuchsin serves as the primary stain, identifying mycobacteria by coloring them red.
4. The effectiveness of a primary stain can be influenced by factors such as pH and the presence of certain ions.
5. Primary stains are essential for visualizing structural details under a microscope, aiding in accurate identification and classification.

Review Questions

Related terms

Mordant:

A substance used to set or stabilize stains or dyes on tissues.

Counterstain:

A secondary stain used to provide contrast to the primary stain.

Differential Staining:

Techniques that use multiple stains to distinguish different microorganisms or cellular components.