Nuclear pores are guarded by:

Options

A. DNA
B. Annulus
C. Protein
D. None

Answer

To answer the question "Nuclear pores are guarded by:", we can break down the information into clear steps:

### Step-by-Step Solution:

1. **Understanding Nuclear Pores**:
- Nuclear pores are openings in the nuclear envelope that allow communication between the nucleus and the cytoplasm. They are essential for the transport of molecules such as RNA and proteins.

2. **Structure of Nuclear Pores**:
- Each nuclear pore is surrounded by a structure known as the annulus. This annulus consists of two parts: the outer annulus and the inner annulus.

3. **Composition of the Annulus**:
- Each annulus (outer and inner) is made up of eight globular proteins. These proteins are arranged in a specific manner, forming a structure that resembles spokes on a wheel.

4. **Size of the Components**:
- The globular proteins that make up the annulus are approximately 15 to 20 nanometers in diameter.

5. **Conclusion**:
- Therefore, the nuclear pores are guarded by the annulus, which consists of these globular proteins.

### Final Answer:
Nuclear pores are guarded by **annulus**.

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