Detailed membrane structure was studied only after the advent of ________.

Options

A. electron microscope in 1960
B. electron microscope in 1950
C. cell staining, 1960
D. cell staining , 1950

Answer

To solve the question, "Detailed membrane structure was studied only after the advent of ________," we need to analyze the options provided and understand the historical context of cell membrane studies.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the specific technology or method that allowed for the detailed study of cell membrane structure.

2. **Analyzing the Options**:
- **Option A**: Electron microscope in 1960
- **Option B**: Electron microscope in 1950
- **Option C**: Cell staining in 1960
- **Option D**: Cell staining in 1950

3. **Knowledge of Cell Membrane Studies**:
- The cell membrane is very thin (approximately 8 nm thick) and cannot be effectively observed using a light microscope due to its limited resolution.
- The electron microscope, which was developed in the 1950s, has a much higher resolution and allows scientists to visualize structures at the nanometer scale.

4. **Determining the Correct Option**:
- The electron microscope was indeed invented in the 1950s, and it significantly improved our understanding of cellular structures, including the sandwich model of the cell membrane.
- Therefore, the correct answer must be the electron microscope from the 1950s rather than 1960 or cell staining techniques, which do not provide the same level of detail.

5. **Conclusion**: Based on the analysis, the detailed membrane structure was studied only after the advent of the **electron microscope in 1950**.

### Final Answer:
**The correct option is B: Electron microscope in 1950.**