Which of the following structures controls the transport of the material into and out of living cells or controls permeability
" " Or
Which one of the following does not differ in E. coli and Chlamydomonas

Options

A. Ribosomes
B. Cell wall
C. Cell membrane
D. Chromosomal organisation

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question has two parts. The first part asks which structure controls the transport of materials into and out of living cells or controls permeability. The second part asks which structure does not differ between E. coli and Chlamydomonas.

2. **Identifying the Structure for Part A**: The structure that controls the transport of materials into and out of cells is the cell membrane. The cell membrane is selectively permeable, meaning it regulates the movement of ions and molecules, allowing some substances to pass while blocking others.

3. **Understanding the Role of the Cell Wall**: The cell wall, in contrast, is fully permeable and allows all substances to pass through. Therefore, it does not control permeability in the same way that the cell membrane does.

4. **Conclusion for Part A**: The correct answer for the first part is the cell membrane, as it is responsible for controlling permeability.

5. **Analyzing Part B**: For the second part of the question, we need to identify which structure does not differ between E. coli (a prokaryotic organism) and Chlamydomonas (a eukaryotic organism).

6. **Comparing Structures**:
- **Ribosomes**: E. coli has 70S ribosomes, while Chlamydomonas has 80S ribosomes. Therefore, ribosomes differ between the two.
- **Cell Wall**: The cell wall of E. coli is made of peptidoglycan, while that of Chlamydomonas is made of glycoproteins. Thus, the cell wall also differs.
- **Cell Membrane**: Both E. coli and Chlamydomonas have a cell membrane composed of a phospholipid bilayer. This structure is common to both types of organisms.
- **Chromosomal Organization**: E. coli does not have histone proteins associated with its DNA, while Chlamydomonas does. Therefore, chromosomal organization differs.

7. **Conclusion for Part B**: The only structure that does not differ between E. coli and Chlamydomonas is the cell membrane.

8. **Final Answer**: The answers to the questions are:
- Part A: Cell membrane (controls transport and permeability).
- Part B: Cell membrane (does not differ between E. coli and Chlamydomonas).

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