In eukaryotic chromosome structure, what forms the coiled structure made of DNA and proteins that can further condense into visible chromosomes during cell division?

• A. The nuclear envelope
• B. The nucleolus
• C. Chromatin
• D. The centromere

Answer: (C)

Verified step by step guidance

1. Understand that eukaryotic chromosomes are composed of DNA and proteins, primarily histones, which together form a complex called chromatin.
2. Recognize that chromatin exists in two forms: euchromatin (less condensed, transcriptionally active) and heterochromatin (more condensed, transcriptionally inactive).
3. Know that during most of the cell cycle, DNA is in the form of chromatin, which is a coiled structure allowing efficient packaging of DNA within the nucleus.
4. During cell division, chromatin further condenses and coils tightly to form visible chromosomes, which ensures proper segregation of genetic material.
5. Identify that the nuclear envelope and nucleolus are distinct nuclear structures, and the centromere is a specific chromosome region, so the coiled structure made of DNA and proteins is chromatin.