Which statement about the outer membrane is true?

Which statement about the outer membrane is true?

• A. It forms the nuclear lamina directly
• B. It is continuous with the ER and may have associated ribosomes
• C. It is not connected to the ER and contains no ribosomes
• D. It is a single sheet with no ribosomes

Answer: (B)

The outer membrane of the nucleus is part of the nuclear envelope and is continuous with the rough endoplasmic reticulum, so it shares the same surface features and can have ribosomes attached to its cytosolic face. This connection explains why the outer membrane may appear ribosome-covered, similar to the rough ER, and why the perinuclear space is continuous with the ER lumen. This is why the statement that the outer membrane is continuous with the ER and may have associated ribosomes is the best choice. The nuclear lamina is formed on the inner surface of the nuclear envelope by lamins, not by the outer membrane. The outer membrane is part of a double membrane system and can have ribosomes, so describing it as a single sheet with no ribosomes isn’t accurate.

The outer membrane of the nucleus is part of the nuclear envelope and is continuous with the rough endoplasmic reticulum, so it shares the same surface features and can have ribosomes attached to its cytosolic face. This connection explains why the outer membrane may appear ribosome-covered, similar to the rough ER, and why the perinuclear space is continuous with the ER lumen.

This is why the statement that the outer membrane is continuous with the ER and may have associated ribosomes is the best choice. The nuclear lamina is formed on the inner surface of the nuclear envelope by lamins, not by the outer membrane. The outer membrane is part of a double membrane system and can have ribosomes, so describing it as a single sheet with no ribosomes isn’t accurate.