Ribophorin occur on the surface of :-

Options

A. Rough E.R.
B. Smooth E.R.
C. Golgi body
D. None

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks where ribophorin is located. Ribophorin is a protein that is associated with certain cellular structures.

2. **Identifying the Options**: The options provided are:
- a) Rough endoplasmic reticulum
- b) Smooth endoplasmic reticulum
- c) Golgi body
- d) None

3. **Defining Ribophorin**: Ribophorin is a protein that is known to be associated with ribosomes, which are the sites of protein synthesis.

4. **Analyzing the Rough Endoplasmic Reticulum (RER)**: The rough endoplasmic reticulum is characterized by the presence of ribosomes on its cytoplasmic surface. This gives it a "rough" appearance under a microscope.

5. **Connection Between Ribophorin and RER**: Ribophorin is specifically found on the surface of the rough endoplasmic reticulum. It plays a role in the attachment of ribosomes to the endoplasmic reticulum.

6. **Excluding Other Options**:
- The smooth endoplasmic reticulum does not have ribosomes on its surface, hence ribophorin would not be present there.
- The Golgi body is involved in processing and packaging proteins but does not have ribophorin on its surface.
- The option "none" is also incorrect as ribophorin is indeed present on a specific structure.

7. **Conclusion**: Based on the analysis, the correct answer is that ribophorin occurs on the surface of the rough endoplasmic reticulum.

### Final Answer:
Ribophorin occurs on the surface of the **rough endoplasmic reticulum**.

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