Bacterial cells can be stained with

Options

A. Mercuric chloride
B. Crystal violet
C. Crystal violet+ iodine
D. Safranin.

Answer

**Step-by-Step Solution:**

1. **Understanding Bacterial Staining**: Bacterial cells can be stained using various dyes, with the most common method being the Gram staining technique. This method classifies bacteria into two groups: Gram-positive and Gram-negative.

2. **Gram Staining Process**: The Gram staining process involves several steps:
- First, bacterial cells are treated with a primary stain, which is typically crystal violet (also known as gentian violet). This dye stains all bacteria blue.
- Next, a mordant (iodine solution) is applied, which helps fix the dye to the bacterial cells.
- After that, the cells are washed with alcohol or acetone. This step differentiates the two types of bacteria:
- Gram-positive bacteria retain the blue color because of their thick peptidoglycan layer in the cell wall.
- Gram-negative bacteria lose the blue color and become colorless due to their thinner peptidoglycan layer.

3. **Counterstaining**: To visualize Gram-negative bacteria, a counterstain such as safranin is applied. This will stain the Gram-negative bacteria pink/red, allowing for differentiation under a microscope.

4. **Conclusion**: Therefore, bacterial cells can be stained with:
- Crystal violet (primary stain)
- Iodine (mordant)
- Safranin (counterstain for Gram-negative bacteria)

5. **Final Answer**: The correct dyes for staining bacterial cells are crystal violet and iodine for Gram-positive bacteria, and safranin for Gram-negative bacteria.

---