Which of the following features confers survival advantage to archaebacteria in extreme conditions as compared to other bacteria?

Options

A. peptidoglycan cell membrane
B. different cell wall structure
C. presence of pigmented cell wall
D. ability to reduce sulphur to H_2 S

Answer

To solve the question regarding which feature confers a survival advantage to archaebacteria in extreme conditions compared to other bacteria, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Differences Between Archaebacteria and Eubacteria**:
- Archaebacteria and eubacteria (true bacteria) have distinct structural differences, particularly in their cell walls and membranes.

2. **Analyze the Composition of Cell Walls**:
- Eubacteria have cell walls made of peptidoglycan, which is a polymer of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).
- In contrast, archaebacteria possess cell walls composed of complex polypeptides and polysaccharides, and they often contain a substance called pseudomurein instead of peptidoglycan.

3. **Evaluate the Options Provided**:
- **Option 1: Peptidoglycan cell membrane** - This is incorrect as archaebacteria do not have peptidoglycan in their membranes.
- **Option 2: Different cell wall structure** - This is correct. The unique composition of the cell wall in archaebacteria allows them to withstand extreme environments.
- **Option 3: Presence of pigmented cell wall** - While some archaebacteria have pigmented components (like bacteriorhodopsin), this does not directly confer survival advantages in extreme conditions.
- **Option 4: Ability to reduce sulfur to H2S** - This is incorrect as archaebacteria typically oxidize sulfur rather than reduce it.

4. **Conclude the Answer**:
- The feature that confers a survival advantage to archaebacteria in extreme conditions is the **different cell wall structure** (Option 2). This unique composition helps them survive in harsh environments like high salinity, extreme temperatures, and acidic or alkaline conditions.

### Final Answer:
The feature that confers survival advantage to archaebacteria in extreme conditions compared to other bacteria is **the different cell wall structure**.

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