It is very important because mitosis is basically replicating your DNA to make more cells that are exact replicas of each other. This is essential because if they are not exact replicas your body's immune system might not recognize it and so it will attack its own body's cell.
There are certain checkpoints throughout mitosis to ensure that everything is going ok, but if we suppose the errors pass the checkpoint and the cell divides from one to two daughter cells. If there is a genetic defect, where one daughter cell has more and one daughter cell has less chromosomes, both will be affected by it. This is called Nondisjunction which is the result of failure of chromosomes to separate during mitosis. This leads to new cells with either extra or missing chromosomes; a condition called aneuploidy.
SO what happens, they might be killed by body's own immune system. There might be apoptosis, which is a form of programmed cell death that occurs in multicellular organisms
What I know is that amino acid has side chain, amine groupe ,and groupe of carboxyl so what make them difference is side group where the is 20 different R-group which give each individual characteristics
