Stages of Mitosis

Hey your daughter looks just like you! Oh! See she has the same mole on the right cheek like her father. Oh she resembles her grand mom so much! Your son or daughter shares some of your qualities and attributes because of the process of Mitosis in which the cell duplicates the chromosomes in the nucleus to produce two identical daughter nuclei. After Mitosis the cell goes through Cytokinesis, which further divides the cell into two more cells that would have equal measure of cellular components like cytoplasm, cell organelles, nuclei and cell membrane.

The physical process of mitosis is complex and controlled to a large extent. The succession that the process follows is divided into phases, equating to the completion of one set of activities and the beginning of the next set of specific processes. These stages in which Mitosis is divided into are Interphase, prophase, prometaphase, metaphase, anaphase and telophase. During all these phases of the process of mitosis, the pairs of chromosomes cluster and combine together and attach to fibers that pull the sister chromatids to opposite sides of the cell. The cell division then takes place in Cytokinesis so that two identical daughter cells can be produced.

Various Stages of Mitosis
Lets take a closer look at the various stages that the process goes through.

Interphase-It is better to inform you beforehand that interphase is not a stage in Mitosis. It is actually a phase of the cell cycle but then it is being mentioned here since it is important to the process of Mitosis. Prior to entering the phase of Mitosis it goes through a phase of growth and that stage is called interphase. Major part of the time taken in cellular cycle is taken up by Interphase. In this phase the cell prepares itself for division. This stage is again divided into three phases G1, the phase prior to the phase of DNA synthesis wherein the phase increases in mass. This is the first gap (Gap1 or G1) of the process of Interphase. Then the phase of Synthesis (S) comes wherein the DNA is synthesized. Then comes the G2 phase, that is Gap 2 in which the cell accumulates more and more protein and continues growing. The cell also keeps on adding organelles.

Prophase- In prophase first the nucleus membrane breaks, the chromosomes shorten and become thicker. It migrates toward two poles of the cell. It happens somewhat like this, the chromatin condenses to become chromosomes. The chromosome divides into two and they are at the two ends bound at one point called the centrometer, thus forming an X.

Prometaphase-The nuclear membrane totally breaks apart and the microtubules start coming inside the nuclear space and this is when it is called "open mitosis" and this stage is common in most of the multicellular organisms, though it is not a phase that can be seen in unicellular organisms. Later in this stage the specialized parts in the region of centromeres of chromosomes attach themselves to the kinetochore fibers, which in turn react with polar fibers. The chromosomes start moving to the center of the cell. This is sometimes called a part of the initial phase of Prophase.

Metaphase-In this phase the spindle that was formed reaches the climax and the chromosomes start aligning themselves in a phase called Metaphase plane, which is at equal distance from the two poles of the spindle. In this phase the nuclear membrane completely disintegrates and the centrioles that are four in number place themselves in a set of two at the opposite poles. Polar fibers can still be found which extend across the length of the cell from one pole to the other. Chromosomes are at right angles to the spindle poles and are held by forces of the same level of polar fibers.

Anaphase-In this phase the paired chromosomes dissociate themselves and start moving towards the opposite poles of the cell and the spindle fibers that are free increase in length resulting in the elongation of the cell body. The centromeres move apart and each of the paired chromatids is now taken as a separate chromosome, in fact daughter chromosomes. As a preparation of the next stage of Telophase the cell poles also move apart and both the ends now almost have a complete compilation of cell organelles.

Telophase-Ultimately in telophase the chromosomes are finally separated into two distinct bodies. This phase is often called the turnaround of prophase and prometaphase stages since the process of formation that was followed during those two phases is repeated in this penultimate phase. A nucleus comes at the poles and the nuclear envelopes are also formed.

This is the overall description of the process of mitosis and the phases since they differ from organism to organism, thus to understand the process for a particular animal requires a lot more detailed analysis.

After Mitosis, there is this process of Cytokinesis which is not a stage of Mitosis but still an integral part of the whole procedure that is initiated in Mitosis. In this the cytoplasm of the original cell divides itself thus forming the base for the two daughter chromosomes to emerge.