Question

When does chromosome replication take place in mitosis? versus when do chromosomes divide in mitosis? What is the difference between chromosomes and sister chromatids?

Answer 1

Answer)Replication of DNA occurs at S phase. of mitosis.

Mitosis consists of five active steps:

prophase, prometaphase, metaphase, anaphase, and telophase

before a cell can enter mitosis, however, it firstly goes through a period known as interphase, during which it grows and produces the various proteins necessary for division. Then, at a critical point during interphase (called the S phase), the cell duplicates its chromosomes and ensures its systems are ready for cell division. If all conditions are ideal, the cell is now ready to move into the first phase of mitosis.

The difference between chromosome and sister chromatid is:

A chromosome consist of a DNA double helix bearing a linear sequence of genes.

The DNA is coiled and recoiled around proteins called histones. The resulting complex is called chromatin.

During the cell division, more precisely during the S-phase of interphase, DNA is replicated. The resulting two identical copies of DNA are connected to each other at the centromere. Each copy is called a chromatid.