Gram stain represents

Options

A. A technique for staining bacteria and developed by Gram
B. A stain got from Gram
C. A cytochemical technique for diffferenti-ation of mitochondria.
D. A trade name.

Answer

**Step-by-Step Solution:**

1. **Understanding Gram Stain**: The Gram stain is a method developed by Christian Gram in 1884 to differentiate bacterial species into two groups based on their cell wall composition.

2. **Components of Gram Stain**: The Gram stain involves using an alkaline solution of crystal violet or gentian violet as the primary dye. This dye is used to stain all bacteria initially.

3. **Staining Procedure**:
- First, bacteria are treated with the crystal violet dye, which stains all bacteria blue.
- Next, a 0.5% iodine solution is applied, which helps to fix the dye within the cells.
- After this, the bacteria are washed with absolute alcohol (100% alcohol).

4. **Differentiation**:
- Gram-positive bacteria retain the blue color after the alcohol wash because of their thick peptidoglycan layer in the cell wall.
- Gram-negative bacteria lose the blue color because they have a thinner peptidoglycan layer and an outer membrane that allows the dye to wash out.

5. **Final Staining**: If further differentiation is needed, Gram-negative bacteria can be stained with a counterstain, such as safranin, to visualize them under a microscope.

6. **Conclusion**: The Gram stain represents a technique for staining bacteria to differentiate between Gram-positive and Gram-negative bacteria based on their cell wall properties.

**Final Answer**: The Gram stain represents a technique for staining bacteria developed by Christian Gram.

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