Our cells are dividing and are being replaced every second of every day. If a cell is damaged or becomes too old, the DNA is replicated and a new daughter cell is produced. By that logic, we should carry on living until a disease is caught, or something causes vital organs to stop working, right? So, why don’t we live forever?
What is a Genetic Mutation?
To begin to answer this question, we must understand what a genetic mutation is. Imagine you are asked to copy an article word for word, letter for letter – a mistake in the copying process, is the equivalent of a mutation in one’s genetic information. Before our cells die, a process called mitosis occurs which is the fancy word for cell division. It results in 2 daughter cells with the exact same DNA as the original.
There are special proteins in the nucleus which copy the DNA very well and efficiently; and once a copy has been made, there is another protein that runs through the copied code and checks no mistakes have been made. The cell copies DNA incredibly well with very minimal mistakes; but we must consider how often this process occurs, which is all the time. Since this is the case, a mistake is bound to happen at some point.
Imagine you are copying an article, then you copy the article you just copied, then copy the article that you copied from the article you copied at the start – and repeat – and again… eventually you are most likely going to make a mistake, then you will be copying that mistake, and you will eventually make a mistake again and copy that mistake over and over. This is what happens as we age; mistakes become abundant in our DNA and eventually one of these mutations cause cancer in a lot of cases.
What are Telomeres?
Cancer is not the only reason we cannot live forever. Telomeres are the tips of each chromosome as shown in the picture below. With each cell division, these telomeres become shorter and shorter – when they run out, the cell dies. Theories also suggest this is why we age.
Stem cell availability?
Stem cell availability also decreases as one ages. Stem cells are non-specialized cells that have the ability to specialize, in order to replace damaged cells in your body. Stem cells also undergo mitosis as they cannot live forever; this means mutations can also occur in them too. As a result, these cells burn out and healthy stem cells become lesser available as one ages.
The human body is an incredible piece of art but as with anything, it has its limitations. We all have one thing in common. Unfortunately that is that we are all going to experience death at some point.
If you have any questions, leave them below and until next time, take care.
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