How DNA Molecules are Stored in the Nucleus

Subject : Biology

Question:

How are DNA molecules stored in the nucleus?

A. Bound via RNA to the nuclear envelope.

B. Complexed with protein, forming chromatin.

C. Complexed with protein on the nuclear envelope.

D. As free molecules.

Expert Verified Solution:

The correct answer is B. Complexed with protein, forming chromatin.

DNA molecules in the nucleus are not stored as free strands or directly bound to the nuclear envelope. Instead, they are organized into a complex with proteins known as histones. This combination of DNA and proteins is called chromatin. Chromatin helps to package the long DNA molecules into a more compact, manageable form that fits within the nucleus. Additionally, this packaging is crucial for regulating gene expression and DNA replication.