Transport of RNA and protein molecules in between nucleus and cytoplasm in both directions is facilitated by

Options

A. RER
B. Nuclear envelope
C. Nuclear pores
D. Perinuclear space

Answer

To answer the question regarding the transport of RNA and protein molecules between the nucleus and cytoplasm, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks which cell organelle facilitates the transport of RNA and protein molecules between the nucleus and the cytoplasm in both directions.

2. **Analyze the Options**:
- **Rough Endoplasmic Reticulum (RER)**: This organelle is primarily involved in the synthesis of proteins. While it plays a role in protein production, it does not directly facilitate the transport of RNA and proteins between the nucleus and cytoplasm.
- **Nuclear Envelope**: This structure separates the nucleus from the cytoplasm. It provides a boundary but does not actively transport molecules.
- **Nuclear Pores**: These are complex structures that span the nuclear envelope. They allow the passage of small polar molecules as well as larger macromolecules, such as RNA and proteins, between the nucleus and cytoplasm.
- **Perinuclear Space**: This is the space between the inner and outer membranes of the nuclear envelope. It does not play a role in the transport of molecules.

3. **Identify the Correct Answer**: Among the options, the nuclear pores are specifically designed to facilitate the transport of RNA and proteins between the nucleus and cytoplasm. Therefore, the correct answer is **nuclear pores**.

4. **Final Answer**: The transport of RNA and protein molecules in both directions between the nucleus and cytoplasm is facilitated by **nuclear pores**.