Gram (-) ve bacteria in Gram stain appears

Options

A. red
B. Colourless
C. blue
D. orange

Answer

**Step-by-Step Solution:**

1. **Understanding Gram Staining**:
- Gram staining is a laboratory technique used to differentiate bacterial species into two groups based on the characteristics of their cell walls.

2. **Types of Bacteria**:
- There are two main types of bacteria identified by this method: Gram-positive and Gram-negative.

3. **Cell Wall Composition**:
- Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which retains the crystal violet stain used in the procedure, resulting in a purple color.
- In contrast, Gram-negative bacteria have a much thinner peptidoglycan layer and an outer membrane, which does not retain the crystal violet stain.

4. **Staining Process**:
- During the Gram staining process, after applying the crystal violet stain, a decolorizing agent (usually alcohol) is used. This agent washes out the stain from Gram-negative bacteria due to their thin peptidoglycan layer.

5. **Counterstaining**:
- After decolorization, a counterstain (usually safranin) is applied. Gram-negative bacteria take up this counterstain, which gives them a red color.

6. **Conclusion**:
- Therefore, Gram-negative bacteria appear red when observed under a microscope after the Gram staining procedure.

**Final Answer**: Gram-negative bacteria in Gram stain appears red.

---