Question

What is the significance of DNA replication during the Sphase of the cell cycle?

O It allows daughter cells to have DNA that differs from the parental DNA.
O It allows daughter cells to have an exact copy of the parental DNA.
O It allows daughter cells to grow in size before they can enter cell division.
O It allows daughter cells to produce the cell organelles needed for life processes.

Answer 1

It allows daughter cells to have an exact copy of the parental DNA

Step-by-step explanation:

In human mitosis, we are taking a cell with 46 chromosomes and we are creating two new daughter cells both with 46 chromosomes genetically identical to the parent cell. How do we do that? Through replication of the chromosome in S phase. Replicated chromosomes allow the chromatids to be separated during anaphase. If I have 46 chromosomes at the beginning of mitosis that are all duplicated that means I have 92 chromatids. If half of all the chromatids go into once cell and half into the other, then 96/2 would be 46 chromosomes. The trick is remembering that a chromosome can have either one or two chromatids. Duplicated ones have two chromatids but are still considered one chromosome. Therefore, by the end of mitosis I have 46 chromsomes in each cell, they are just unreplicated chromatids, which were allowed to be separated since they were duplicated in S phase.