stages of mitosis

Do you know how cancer happens? It's not just some random bundle of abnormal tissues that get tucked within a particular organ overnight! A cancer is the body's way of playing the devil with you, using the very same resources which nature originally equipped it with and which it is supposed to use for the growth, replacement and reparation of dead or damaged tissues. Oh yes, I am talking about cells alright! So, what is it about cells that the body can manipulate, unintentionally of course (you sink, your body sinks so it has to play along.... it's as simple as that), in such a way that in due course of its being created, it turns on a deviant path and becomes cancerous? Now we're talkin'! Pay close attention to the following segment about mitosis and cancer relationship to properly grasp the finer, more complex nuances of this subject.

What is the Link Between Mitosis and Cancer?

Continuing from where I left in the previous paragraph, a cancer cell is nothing but a regular cell with its DNA gone crazy! You see, the way a cell behaves right from the time it grows through the functional duration of its life cycle till its eventual, and necessary, death, the genetic matter present inside it decides what course it will take, how long will its life be and, most importantly, what growth trend will it exhibit. This last factor is what primarily differentiates a cancer cell from a normal one. Okay, let me put it this way. A cell begins its existence as a cancer cell as soon as its inception starts. When all biological matter is assembled for putting together a single cell, the genetic matter, the DNA, undergoes an abnormal mutation. Say, for instance, out of a batch of a thousand new cells, the DNA of one cell shows this mutation and, as a result, begins growing abnormally, turning into a cancer cell.

Just how much harm can one abnormal cell among a million normal ones (the thousand new plus the remaining pre existing ones) do? This is where mitosis comes into the picture. In case you're not very clear about the nitty-gritties of cellular biology, mitosis is the process wherein a fully developed, mature cell divides into two, much like the way many micro organisms undergo binary fission to reproduce. You see, when a cell has grown to a certain stage, it becomes ready for division into two identical cellular units, having the exact same number of chromosomes, DNA structure and all other elements of cellular architecture. Now, mitosis is that part of this preparatory phase (for cell division) where the parent cell makes an identical copy of its genome (which is composed of chromosomes) such that on division, both daughter cells will have the exact same genomic structure and characteristics as the parent cell had before division. Get the wind yet? No? Well, since a cell becomes cancerous and shows abnormal growth owing to the development of a DNA mutation within its genome, mitosis just plays the role of a genetic photocopy machine - it makes identical copies of the parent cell's genome, mutation and all!

So, once cellular division happens, what began as a pro-cancer mutation in a single cell multiplies twofold and that's just the beginning. As these daughter cells mature and prepare for cellular division in their respective eukaryotic cycles (oh yes, mitosis occurs only in eukaryotic cells), they also undergo mitosis, the mutated DNA gets copied yet again and now, instead of two, there are four cancer cells in the body. This chain continues till the abnormal cells grow so large in number that they manifest their presence as malignant tissue growths and tumors. Mitosis is the process by which genetic matter gets identically replicated many times over. Since cancer is caused by a damage or mutation to cellular DNA, mitosis plays an active role in spreading cancer in the body by making exact copies of these damaged and mutated cellular genetic materials. Medical intervention is the only way to stub out this type of malignant cellular propagation in the body
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.