A Gram negative bacteria differ from a Gram positive bacteria in having

Options

A. Thick cell wall and is primarily made up of peptido- glycan
B. Complex cell envelope made up of three layers
C. cell wall of 20- 80 nm in thickness and also contams tightly bound techoid acids
D. Absence of cell wall lipids

Answer

To answer the question of how Gram-negative bacteria differ from Gram-positive bacteria, we can analyze the characteristics of both types of bacteria step by step.

### Step-by-Step Solution:

1. **Understanding Gram Staining**:
- Gram staining is a method used to differentiate bacterial species into two groups based on the structural differences in their cell walls.
- Gram-positive bacteria retain the crystal violet dye and appear purple/blue under a microscope, while Gram-negative bacteria do not retain the dye and appear pink/red.

2. **Cell Wall Structure**:
- **Gram-positive bacteria** have a thick peptidoglycan layer (20-80 nm) that retains the dye during the staining process. This thick layer is primarily made up of peptidoglycan.
- **Gram-negative bacteria**, on the other hand, have a much thinner peptidoglycan layer and are surrounded by an outer membrane that contains lipopolysaccharides.

3. **Presence of Outer Membrane**:
- Gram-negative bacteria possess an outer membrane that is absent in Gram-positive bacteria. This outer membrane contributes to their structural complexity and is a significant distinguishing feature.

4. **Teichoic Acids**:
- Teichoic acids are present in the cell walls of Gram-positive bacteria but are absent in Gram-negative bacteria. This is another important difference.

5. **Cell Wall Lipids**:
- Gram-negative bacteria have lipids in their outer membrane, while Gram-positive bacteria do not have this outer membrane and thus lack these lipids.

### Conclusion:
Based on the analysis, the correct answer to the question is that Gram-negative bacteria differ from Gram-positive bacteria in having an **absence of cell wall lipids**.