The Theory of Nothing

How does mitosis work?

How does mitosis work?

Thanks to @Akhyitah for the Haflick limit idea.

Mitosis is a fancy scientific term for cell division, the most important reproduction process in nature. Mitosis is by definition the process that divides the nucleus of a cell into replicates that form two identical new cells by a process known as cytokinesis. Every cell in your body does this on a regular basis to keep you fresh. It's one of the main things that your body does while it's alive.

Why is this so important? The reason is because errors in the mitosis process can cause cancer. Let's explore why this is. The first step in the mitosis process, actually even before it starts, is the replication of chromosomes of the nucleus. Chromosomes contain the DNA that defines you as an organism. Keep in mind that mitosis is a very complicated process and even more important, no one knows why it happens.

Here is what happens step by step:

Interphase: The cell gets ready to do its thing. The cell grows larger (by producing proteins and organelles) before it splits its nuclei chromosomes. Special proteins (cyclin) and enzymes (cyclin dependent kinases) regulate all of these processes.

Prophase: The cell forms mitotic spindles from two centrosomes (round structures that act as coordinating bosses). These filaments act like guiding wires for the DNA molecules in the chromosomes to split properly.

Prometaphase: The nucleus disintegrates and the microtubule (the spindles) from each centrosome get intimate, making connections to form guiding wires.

Metaphase: The chromosomes get organized and lined up for the split up.

Anaphase: This is where the lined up chromosomes split forming what are known as identical daughter cells.

Telophase: Nuclei material surrounds the two batches of chromosomes.

Cytokinesis: The two new cells separate.

Mitosis occurs at an accelerated level during embryo development. Errors in the anaphase step can cause a failure to go through the cytokinesis step or even cause some of the chromosomes to not split correctly. These errors result in birth defects.

There is a limit to the number of times that human cells can undergo mitosis. It's known at the Hayflick limit, named for Leonard Hayflick, and anatomist that discovered this limit in 1981. This is important because it could be the reason that we don't live as long as we should. If a method could be found to extend this limit, humans lifespan could be increased, assuming that it wouldn't result in cancer.

Cancer occurs because of damage to the chromosomes before mitosis. This results in cells that split too much or too quickly and form a tumor. Mitosis is a carefully controlled process, obviously ruled by DNA coding that produces the enzymes and proteins that regulate mitosis. When mitosis isn't regulated cells go wild. Cancer by definition is abnormal cell growth. In other words it's cells that grow too much and form a tumor that disrupts other normal cells. This abomination has to involve these regulators that control mitosis. Obviously, cancer is a very complicated subject and most of the stuff written about it involves environmental causes like radiation, chemicals, smoking etc. This disease needs more fundamental work down at the microbiological realm.

The other thing that's weird about cancer is the fact that it can spread to other parts of the body. This means that there are messenger cells from cancer cells that get into the blood stream and find new cells to infect. I would propose that this is a virus or some other infectious agent that has been around since the beginning of the evolution of life. Our immunity systems have evolved to fight this whatever it is. When our immunity systems are compromised, cancer has its way. Proof of this is HIV. People with this disease have all sorts of strange, unusual cancers because their immunity systems are infected and destroyed. Their immune systems no longer can differentiate between good cells and bad cells.

One of the things about cancer that physicians have noted is wasting. Wasting causes a cancer patient's muscle and fat tissues to deteriorate, which impedes their ability to withstand rigorous chemotherapy or radiation treatment. Researchers have discovered a protein (ImpL2) that's responsible for this wasting, which is called cachexia. This protein is released by the tumor but it doesn't affect the tumor itself. Hopefully, this discovery will lead to a treatment for cachexia.

A new theory links cancer to the process of wound healing, a process that steps up cell division to produce new tissue. This involves stem cell activation and this is a natural process. However, if the wound healing process is not abated, it will produce a tumor. I don't know if this has been proven, but it is interesting. In any event, the mitosis process plays a part in all of this.

Thanks for reading.