An onion root tip cell contains 16 chromosomes and a 2 C amount of DNA during the G₁ phase of the cell cycle. What will be the respective number of chromosomes and the amount of DNA in this cell after the completion of the S phase?

Step-by-step solution

During the G₁ phase, the onion root tip cell has 16 chromosomes and a 2 C amount of DNA. In the S phase (synthesis phase) of the cell cycle, DNA replication takes place. This causes the amount of DNA in the cell to double, increasing from 2 C to 4 C . However, the number of chromosomes remains unchanged because the newly synthesized sister chromatids remain attached at the same centromere. The chromosome number only changes when sister chromatids separate during anaphase. Thus, after the completion of the S phase,