Two identical chromosomes that split and contain the same genetic material.

Two identical chromosomes that split and contain the same genetic material.

• A. Chromosomes
• B. Chromatids
• C. Genes
• D. Nucleotides

Answer: (B)

Two identical copies that stay attached and later separate are sister chromatids. They are produced when a chromosome is replicated during S phase, creating two identical DNA molecules held together at the centromere. They stay together until anaphase of cell division, when the centromeres split and each chromatid becomes an individual chromosome going to a daughter cell. Because they come from the same DNA, they carry the same genetic information. Chromosomes, genes, and nucleotides don’t fit this description as neatly. A chromosome can refer to a single piece of DNA, not necessarily a replicated pair. Genes are the functional units of heredity, not copies of DNA themselves. Nucleotides are the building blocks of DNA, not structures that split into identical copies.

Two identical copies that stay attached and later separate are sister chromatids. They are produced when a chromosome is replicated during S phase, creating two identical DNA molecules held together at the centromere. They stay together until anaphase of cell division, when the centromeres split and each chromatid becomes an individual chromosome going to a daughter cell. Because they come from the same DNA, they carry the same genetic information.

Chromosomes, genes, and nucleotides don’t fit this description as neatly. A chromosome can refer to a single piece of DNA, not necessarily a replicated pair. Genes are the functional units of heredity, not copies of DNA themselves. Nucleotides are the building blocks of DNA, not structures that split into identical copies.