4.4 Mitosis and Cytokinesis
What is meant by the "division of the nucleus"?
Look closely at the microscopic image of cells shown at right. Most of the cells are pretty typical cells full of cytoplasm and a nucleus, busily going about their business, doing what cells do (which of course depends somewhat on what type of cells they are). Do you notice some cells that look a little different than the rest? Instead of a grainy, purple stained nucleus, do some look like they have little "strings" in them? These special cells have left interphase behind and have begun the exciting process of cell division. Specifically, they have begun a part of the cell cycle known as mitosis . This process is sometimes known as the "dance of the chromosomes" . In this section we will discuss the process by which the nucleus of a cell divides and one cell becomes 2 new cells.
Look closely at the microscopic image of cells shown at right. Most of the cells are pretty typical cells full of cytoplasm and a nucleus, busily going about their business, doing what cells do (which of course depends somewhat on what type of cells they are). Do you notice some cells that look a little different than the rest? Instead of a grainy, purple stained nucleus, do some look like they have little "strings" in them? These special cells have left interphase behind and have begun the exciting process of cell division. Specifically, they have begun a part of the cell cycle known as mitosis . This process is sometimes known as the "dance of the chromosomes" . In this section we will discuss the process by which the nucleus of a cell divides and one cell becomes 2 new cells.
Mitosis and Cytokinesis
Remember that during interphase, the cell made an exact copy of its DNA code, so at the beginning of mitosis, each cell is carrying double copies of its DNA code in the form of two identical chromatids held together in the center at the centromere . During mitosis, when the nucleus divides , the two chromatids that make up each chromosome separate from each other and move to opposite poles of the cell. You can watch an animation of the process at the following link: Mitosis Animation |