What are chromosomes?

• A. ribosomes
• B. complex structures made of DNA and histone proteins in the nucleus of cells
• C. circular DNA in mitochondria
• D. cytoskeleton

Answer: (B)

Chromosomes are the organized carriers of genetic information inside the cell nucleus, made of DNA wrapped around histone proteins to form compact, visible structures. This combination allows long DNA molecules to be packaged and organized so genes can be accurately passed on during cell division. In eukaryotic cells, most genetic material exists as chromosomes in the nucleus, and they condense into tightly packed forms when a cell divides to ensure proper separation.

Ribosomes, by contrast, are the molecular machines that synthesize proteins. Mitochondrial DNA is circular and located in mitochondria, not organized into chromosomes within the nucleus. The cytoskeleton is the cell’s structural framework, not genetic material.