The cell is being cleaved into two daughter cells, which occurs during cytokinesis. Sister chromatins separate during anaphase, the nuclear membrane reforms and DNA unwinds during telophase, so the cell has passed those stages leaving only cytokinesis before the daughter cells repeat the process over again. 

The "S" in S phase is short for synthesis, as in DNA synthesis. During this time, each of the organism's chromosomes is copied in order to prepare for cell division so that both daughter cells have the genetic information necessary to be able to function properly. This type of cell division occurs in both somatic, or body, cells and sex cells, but not in prokaryotic organisms.

Mitosis begins with prophase, where the chromatin in the cell condenses into chromosomes. Prophase is followed by metaphase, characterized by the lining up of chromosomes along the metaphase plate. Anaphase is the next stage that begins with the separation of paired chromosomes (sister chromatids). The last stage of mitosis is the telophase, where the chromosomes are cordoned off into new nuclei and return to chromatin form. An easy way to remember this order is to use the acronym PMAT.

Note: Cytokinesis is not technically a part of mitosis, but it is often included. It is an event that directly follows mitosis in which the cytoplasm is divided into two daughter cells. 

During anaphase, chromosomes are split and sister chromatids move to opposite ends of the cell. This separation is caused by the shortening of a pair of spindle fibers attached to the kinetochore of each sister chromatid. The other end of the spindle fibers is attached to a centriole at each respective end of the cell, which pulls the sister chromatids apart as it shortens the fiber.

It is during prophase that DNA condenses from chromatin into chromosomes, and it is during telophase that DNA unwinds from chromosomes back into chromatin. So for every stage between these two DNA is in chromosome form. The only stages between prophase and telophase are metaphase and anaphase. In all other stages DNA is in chromatin form. 

Anaphase is when the chromosomes are pulled apart. An easy way to remember the phases of the cell cycle is by memorizing IP-MAT.

Interphase
Prophase
Metaphase
Anaphase
Telophase

Then remember that the "metaphase plate" is when the chromosomes line up, and right after that is when they are pulled apart, in anaphase.

Each cell goes through the cell cycle and can be at any point within it. During the G1 phase all the components of the cell are duplicated. The cell size increases as they produce RNA and synthesize proteins, as well as increase the number of organelles. During the S Phase DNA replication begins and chromosomes become replicated. Each chromosome will have two sister chromatids, connected at the kinetochore. In the G2 Phase the cell double checks the duplication work and makes necessary repairs so that mitosis can begin.