When Does DNA Replication Occur?
DNA replication occurs in any growing or healing process that the body undertakes, such as new hair growth, fingernail growth or skin growth. Learn about the DNA replication process with information from a biology teacher in this free video on science.
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Have you ever wondered exactly how it that your hair gets longer or that your nails grow or that a cut heals on your skin? I'm Janice Crenetti and I've been teaching biology for over 20 years and I'm here to answer the question, when does DNA replication occur? Well to answer that question we have to talk about a couple different pieces, first of all what's DNA? Well, DNA is the genetic material it's a molecule that's inside the nucleus of all your cells, looks something like this, it actually twists up into what's called a double helix. Well this DNA molecule is the blueprint that makes you. It's what makes a person, a person and a chicken, a chicken and even what makes one person different from another person. I think of it sometimes as being the recipe for putting your body together. Well, anytime there's growth, whether you're getting taller, you're gaining weight or your hair is getting longer. DNA is replicating and what that means is DNA is producing more of itself. Every time your hair grows your hair has basically replicated more cells. The hair cells that you have are divided, actually comes from up here, they divide and make more hair cells and your hair gets longer and longer. The same thing with your fingernails, and the same thing with your skin. Well, cells, every cell before it replicates has to go through something that's called the cell cycle. Cell cycle happens in different phases. The end right here represents something called mitosis. That's where the nucleus of the cell where all the DNA is, is actually lining up and splitting apart, so that those new cells will be exactly alike. These other three components the Gs and G2 represent a time when this cell doesn't look like it's splitting but all the work is going on inside. Right here where it says S, it stands for synthesis, this is the phase in the cell cycle where DNA is actually copying itself. It's making exact copies so when a cell splits in half, each new cell has an exact amount of the same kind of DNA, so that one hair cell is like another hair cell, one skin cell is like another skin cell. The cell has to go through that whole cycle in order for growth to happen. But the DNA replication happens only during one particular part of the cycle. I'm Janice Crenetti and this was, this is, when does DNA replication occur?