We have all had that horrible experience when we fall off our bike and scrape our knee, elbow, or shin. It hurts like the dickens and you run to Mom crying for help. Mother soothes your hurt as best she can and places a band aid on it. Band aids make everything better at that age don’t they? After a while you take your band aid off and there is a scab over the area of the scrape, and over the next few days your scab slowly peels off to reveal new skin underneath it. What has taken place in your body to allow this to happen?
After you scrape yourself, your body forms a crust like object over your cut called a scab in order to protect it from further harm. Under the scab, your cells are hard at work repairing your skin. How does this happen? Well, white blood cells come in and get rid of anything foreign that got in your skin from when you fell: dirt, and bacteria which could potentially make you sick. As they are fighting bacteria and cleaning up the area around your scrape, your skin cells are hard at work reproducing so that a new layer of skin can form. How do they accomplish this? Your cells basically divide themselves forming a new cell. This is an asexual way of reproducing called cell division.
Your cells can make exact copies of their DNA strands by certain enzymes which split the DNA in half. Each separate half is used as a template for the other half forming two new strands of DNA. After this happens, your cell performs the mitosis phase of cell division which is divided into four phases: the prophase, metaphase, anaphase, and telophase (PMAT). After each of these phases are complete, your have two identical cells. This happens under the scab hundreds of times as each cell divides to produce new skin cells.