Bacteria differs from mycoplasma in having :

Question

Accepted Answer

Bacteria differ from mycoplasma primarily in having a rigid cell wall, which is why Option 4 is the correct answer. Here is a detailed explanation:

1. **Rigid Cell Wall (Option 4):** 
   - Bacteria typically have a rigid cell wall composed of peptidoglycan, which provides structural support and shape to the cell. This cell wall is crucial for maintaining the integrity of the bacterial cell, especially in varying environmental conditions.
   - Mycoplasma, on the other hand, lack a cell wall entirely. They are unique among prokaryotes in this regard, which makes them more flexible and able to change shape. This absence of a cell wall is a defining characteristic of mycoplasma and is why they are resistant to antibiotics like penicillin that target cell wall synthesis.

2. **Nucleoides (Option 1):**
   - Both bacteria and mycoplasma have nucleoids. A nucleoid is the region within a prokaryotic cell where the genetic material (DNA) is located. Since both organisms are prokaryotes, they both contain nucleoids, making this option incorrect in differentiating between the two.

3. **Plasma Membrane (Option 2):**
   - Both bacteria and mycoplasma possess a plasma membrane. The plasma membrane is essential for all cells as it controls the movement of substances in and out of the cell. Therefore, this option does not distinguish bacteria from mycoplasma.

4. **70-S Ribosome (Option 3):**
   - Both bacteria and mycoplasma have 70-S ribosomes, which are the sites of protein synthesis in prokaryotic cells. This similarity means that the presence of 70-S ribosomes cannot be used to differentiate between bacteria and mycoplasma.

In conclusion, the presence of a rigid cell wall is the key distinguishing feature between bacteria and mycoplasma, making Option 4 the correct answer.