[Campbell Biology P.300] In which of the following phases or stages of the eukaryotic cell c... | Practice Question

In which of the following phases or stages of the eukaryotic cell cycle do chromosomes typically exist as single, unduplicated DNA molecules?

  • A: S phase and Prophase
  • B: G1 phase and after Anaphase/Telophase
  • C: G2 phase and Metaphase
  • D: Mitotic M phase (excluding Anaphase)

Explanation

Chromosomes exist as single, unduplicated DNA molecules during the G1 phase, before DNA replication occurs in the S phase. After DNA replication S phase and through G2, prophase, prometaphase, and metaphase, chromosomes consist of two identical sister chromatids. In anaphase, these sister chromatids separate, and each separated chromatid is then considered an individual chromosome again, effectively becoming a single, unduplicated DNA molecule for the daughter cell.