Bacteria are classified on the basis of

Options

A. Nucleus
B. Cell wall
C. Gram +ve and Gram -ve
D. cytoplasm

Answer

**Step-by-Step Solution:**

1. **Understanding Bacterial Classification**: Bacteria are classified based on various characteristics, including shape, cell wall composition, flagella presence, and nutritional requirements.

2. **Focus on Staining**: One of the primary methods of classifying bacteria is through a staining technique known as Gram staining. This method divides bacteria into two main categories: Gram-positive and Gram-negative.

3. **Gram-Positive Bacteria**:
- These bacteria retain the crystal violet stain used in the Gram staining process.
- Under a microscope, they appear violet or purple.
- An example of a Gram-positive bacterium is *Streptococcus aureus*.

4. **Gram-Negative Bacteria**:
- These bacteria do not retain the crystal violet stain and instead take up the counterstain (usually safranin), appearing red or pink under the microscope.
- An example of a Gram-negative bacterium is *Escherichia coli* (E. coli).

5. **Conclusion**: While bacteria can be classified based on several criteria, the most significant and widely used classification is based on their response to Gram staining, categorizing them as either Gram-positive or Gram-negative.

**Final Answer**: Bacteria are classified on the basis of Gram-positive and Gram-negative staining.

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