What structure surrounds the nucleolus and DNA and regulates entry and exit of materials to the nucleus?

What structure surrounds the nucleolus and DNA and regulates entry and exit of materials to the nucleus?

• A. Nuclear membrane/envelope
• B. Cytoplasm
• C. Nucleolus
• D. Nuclear pore

Answer: (A)

The boundary that encloses the nucleus, including the nucleolus and its DNA, is the nuclear envelope. This double membrane creates a distinct nuclear environment and is perforated by nuclear pores. Those pores act as gatekeepers, controlling what enters and leaves the nucleus—RNA, proteins, and ribosomal subunits move through them as needed—while keeping the genetic material protected from the cytoplasm. The cytoplasm surrounds this boundary, the nucleolus sits inside the nucleus, and a nuclear pore is a feature of the envelope, not the surrounding structure itself.

The boundary that encloses the nucleus, including the nucleolus and its DNA, is the nuclear envelope. This double membrane creates a distinct nuclear environment and is perforated by nuclear pores. Those pores act as gatekeepers, controlling what enters and leaves the nucleus—RNA, proteins, and ribosomal subunits move through them as needed—while keeping the genetic material protected from the cytoplasm. The cytoplasm surrounds this boundary, the nucleolus sits inside the nucleus, and a nuclear pore is a feature of the envelope, not the surrounding structure itself.