All cells arise from the growth and division of pre-existing cells. It is now possible to watch this process and study the mechanisms where by cells reproduce asexually. Scientists can even see, identify and count the number of chromosomes carried by any cell of any species of organism.
The starting material for such studies is very often rapidly growing cells. Which can be stopped in various parts of the cell cycle and examined by a variety of techniques.
For most of its life, a cell does not look very active, at least when examined using a light microscope. This period, called interphase, is, however, a very dynamic part of a cell's life where molecules are made and broken down and energy is metabolized.
During nuclear division it is possible to see various events happening with the DNA and chromosome. The first of these is called prophase, which is the first stage in which the cell's chromosomes actually become visible.
During metaphase many concurent events lead to the aligning of the chromosomes in the middle of the cell, attached by their centromeres to contractile fibers of protein - the spindle apparatus.
Anaphase is when the action starts and the two equal parts of the chromosomes are finally separated and pulled to opposite poles of the cell.
The the two halves of the cell begin to split, starting in telophase with the unpacking of the chromosomes and the recreation of two new, daughter nuclei.
Finally the cytoplasm of the cell, and all its contents, is divided between the two new daughter cells during cytoplasmic division.