There are different stages of the cell cycle. They get divided by completing several tasks. Firstly, it must grow and copy its genetic material which is called DNA, then they physically split into two daughter cells. The cells will perform each of the tasks in a very organised, predictable series of steps which will make up the cell cycle. The cell cycle goes around like a circle rather than a linear pathway, because at the end of each of the go around, the two daughter cells will start at the exact same process over again from the beginning. Mitosis is one of the types in cell division, one of the cells is known as the “the mother”. This cell divides to produce two new cells- “the daughters”. They are genetically identical. In the cell cycle mitosis is the part of the division process where the DNA of the cell’s nucleus splits into two equal sets of chromosomes. A majority of the cell division in the body involves mitosis. Mitosis has five basic phases they are called: Interphase, Prophase, Metaphase, Anaphase and Telophase. During the interphase process the cell replicates its DNA which is chromosomes as it starts to prepare for the division, the chromosomes at this age are not easily visible since they are uncoiled (Cell Division – Binary Fission, Mitosis, Meiosis ; Cancer, 2018).
In early stages of prophase, the cells start to break down some structures and build the others up by setting the stages for division of the chromosomes. Chromosomes in early prophase will start to condense which will make them easier to pull apart later, then the mitotic spindle will begin to form. The spindle is a structure which is made of something called “microtubules”. They are strong fibres that are part of the cells “skeleton”. Its job is to organize the chromosomes by moving them around during mitosis. The “Spindle” will start to grow between the centrosomes as they start to slowly move apart. The nucleolus which is part of the nucleus this is where ribosomes are made, they will start to disappear. This is one of the signs to show that the nucleus is getting ready to break down. In late Prophase the mitotic spindle will begin to capture and organise chromosomes, the chromosomes will finish condensing, so they are very compact. Nuclear envelop will start to break down by releasing the chromosomes. The mitotic spindle grows more so this means some of the microtubules will start to capture chromosomes. In the process of metaphase, the spindle has captured all the chromosomes and started to line them up in the middle of the cell, so its ready to divide. In this stage two of kinetochores in each of the chromosomes will start to get attached to the microtubules from opposite spindle poles. Anaphase the sister of the chromatids will start to separate from each other and is pulled towards opposite end of the cell. The protein which is glued this holds the sister of the chromatids together and is broken down. This allows them to separate, now it is its own chromosome. The chromosomes of each of the pairs are being pulled towards the opposite ends of the cell. The microtubules aren’t attached to the chromosomes elongate so they push apart, this will separate the poles this will make the cell longer.
Finally, in telophase the cell is nearly done in diving and will start to rebuild the normal cell structures as cytokinesis this is when the division of the cell contents will take place. The mitotic spindle has been broken down into its own building blocks, two of the new nuclei will start to form and one of each set of chromosomes for example the nuclear membrane and nucleoli will start to reappear. The chromosomes will begin to decondense by returning to their own stringy form. Lastly one of the other cell division in mitosis is called “Cytokinesis” the division of the cytoplasm will start to form two new cells as they overlap with the final stages of mitosis (cellular-molecular- biology, 2018). This may start to develop in anaphase or telophase, but this will depend on the cell, it will finish shortly after the process of telophase. Finally, the process of cytokinesis finishes there will be two new cells each of them with a complete set of chromosomes identical to those of the mother cell. Then the daughter cells will begin to start their own lives, depending on what they will decide to be once they start to grow up, they may undergo mitosis in this process. When a normal cell goes through mitosis, there will be a numerous of checkpoints where the cell will make sure it’s healthy and ready to divide. For example, if the cell passes through the restriction point which is G1/5 checkpoint. It will be more likely to complete the cell cycle and divide or this can undergo a process called “Apoptosis” this is a process of a programmed cell death. When the cell cycle is disrupted apoptosis arises when the cell has started to sense that the DNA is damaged (profile, 2018). When the cell begins to sense the damage, the cell will try to fix it but if the damage gets too much for the cell, it will lead the cell to die and kill itself, this is called apoptosis- mutation is proliferated to daughter cells. In this case if the process apoptosis does not work with the cells then the damaged DNA will be able to divide, this will lead to accumulation of further mutation. Unfortunately, the process will finally lead to a disease called cancer. Proliferation is referred to a growth and reproduction of cells.
1 Khan academy. 2018. cellular-molecular-biology. ONLINE Available at: https://www.khanacademy.org. Accessed 18 February 2018
2 Criticisms of behaviourism. 2018. Criticisms of behaviourism. ONLINE Available at: http://bradleya.blogspot.co.uk. Accessed 8 February 2018.
3 MicroscopeMaster. 2018. Cell Division – Binary Fission, Mitosis, Meiosis ; Cancer. ONLINE Available at: https://www.microscopemaster.com/cell-division.html. Accessed 29 April 2018.
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