Which one of the following does not differ in E.coli and chlamydomonas?

Options

A. Ribosomes
B. chromosomal organisation
C. cell wall
D. cell membrane

Answer

To determine which characteristic does not differ between E. coli and Chlamydomonas, we need to analyze the key differences and similarities between these two organisms.

### Step-by-Step Solution:

1. **Identify the Organisms**:
- E. coli is a prokaryotic organism, which means it lacks a well-defined nucleus and membrane-bound organelles.
- Chlamydomonas is a eukaryotic organism, characterized by having a well-defined nucleus and membrane-bound organelles.

2. **Cell Structure**:
- E. coli has a simpler structure with a cell wall made of peptidoglycan.
- Chlamydomonas has a cell wall made of cellulose and pectose.
- Therefore, the composition of the cell wall differs between the two.

3. **Ribosomes**:
- E. coli has 70S ribosomes, which are smaller and found in prokaryotes.
- Chlamydomonas has 80S ribosomes, which are larger and found in eukaryotes.
- Thus, ribosomal size differs between the two.

4. **Chromosomal Organization**:
- E. coli has a simpler chromosomal organization, typically a single circular chromosome.
- Chlamydomonas has a more complex organization with multiple linear chromosomes.
- Hence, chromosomal organization also differs.

5. **Cell Membrane**:
- Both E. coli and Chlamydomonas have a cell membrane composed of a phospholipid bilayer with proteins.
- The composition of the cell membrane is similar in both organisms.

### Conclusion:
The characteristic that does not differ between E. coli and Chlamydomonas is the **cell membrane**.

### Final Answer:
**Cell Membrane**