Choose odd one out w.r.t. nuclear membrane.

Options

A. inner mmbrane is smooth
B. Cytoplasmic surface of envelope may bear ribosomes
C. Outer membrane bears 70S ribosomes
D. Peribyclear space is 10 to 50nm

Answer

To solve the question "Choose the odd one out with respect to nuclear membrane," we will analyze each option provided and determine which one does not fit with the characteristics of the nuclear membrane.

### Step-by-Step Solution:

1. **Understanding Nuclear Membrane**:
- The nuclear membrane, also known as the nuclear envelope, is a double membrane structure that surrounds the nucleus in eukaryotic cells. It consists of an inner and outer membrane.

2. **Analyzing the Options**:
- **Option A**: Inner membrane is smooth, cytoplasmic surface may have ribosomes.
- The inner membrane is indeed smooth and does not have ribosomes. The outer membrane, however, is associated with ribosomes due to its continuity with the endoplasmic reticulum.
- **Option B**: Outer membrane has 70S ribosomes.
- This statement is incorrect because the outer membrane contains 80S ribosomes, not 70S. 70S ribosomes are typically found in prokaryotes and mitochondria.
- **Option C**: Perinuclear space is 10 to 50 nanometers.
- This is a correct statement. The perinuclear space, which is the space between the inner and outer membranes, is indeed about 10 to 50 nanometers wide.
- **Option D**: The outer membrane may have ribosomes.
- This is also a correct statement as the outer membrane is continuous with the rough endoplasmic reticulum, which is studded with ribosomes.

3. **Identifying the Odd One Out**:
- From the analysis, Option B is the odd one out because it incorrectly states that the outer membrane has 70S ribosomes, whereas it actually has 80S ribosomes.

### Conclusion:
The odd one out with respect to the nuclear membrane is **Option B: Outer membrane has 70S ribosomes.**

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