 But now we're going to be talking about DNA replication. So what is it? Basically, DNA replication is copying or genetic material. So if we start off with one molecule of DNA, as a result of replication, we end up with two. That's basically what DNA replication is about. Why is DNA replication important? It's important for different things. For example, it's important for cell cycle progression. So if you see this joint here, it depicts the cell cycle. And you have different stages of the cell cycle. I'm not going to go into all of them. I just want you to show you exactly where in the cell cycle does DNA replication occur. It occurs here during the S phase of the cell cycle. So DNA replication occurs during the S phase of the cell cycle because what's going on here is that the cell is preparing for division. So before you can divide your genetic material, you have to duplicate it. Then you do cell division. So just remember that. Also, it's important for inheritance. So in order, again, for us to go through the process of meiosis, which provides a starting material for making an offspring, you have to go through, again, an S phase to duplicate your DNA. And then after the DNA gets duplicated, then you have male tick division, which provides gametes. So you have the female gamete and the male gamete. And these will fuse to give you your zygote, which is going to eventually give you your offspring or your child. Also, DNA is important in repair. So for example, wound repair. On this hand, you notice there's a cut. DNA replication is a process that is actively involved here because for wound repair, you had death to cells. So you have to replace these cells. And how are you going to replace them? You have to have the cells dividing. And in order for the cells to divide, you have to have replication first before you can have cell division. So these are instances in which DNA replication is important. So we already spoke about when DNA replication happens. It happens in the S phase. Now what happens as a result of replication? Basically, the number of DNA molecules will duplicate. So this is just, again, a crude representation of one fragment of DNA molecule in a cell. So this is actually showing the DNA in the nucleus. And then after replication, so this is after the process of DNA replication, you end up with two molecules. And they are called daughter DNA molecules. So it's two daughter DNA molecules. And the important thing about DNA replication is that it goes through a process of what is called semi-conservative replication. And basically what this means is that your starting molecule or your parent molecule is going to produce two daughter molecules. And each of these daughter molecules will have a parent strand. So your daughter molecule, so if you look at this daughter molecule in particular, it has an old strand, which is a strand in black, and then new strand, which is a strand in red. So this comes together to give you your new molecule. So your new molecule is made up of old and new strands. And that is because your DNA, both strands actually serve as templates that you will use to copy the new strand. So as I said, again, DNA replication follows Bayes-Pearing rules. So this is what happens. Both of these strands are going to serve as templates. So what happens as a result of replication? You end up with two molecules. So in this case, you have G, C, T, G, C, A, G, T, and C. And this time, when this gets copied, you're going to end up with your daughter molecule. Your daughter molecule will have C, G, A, C, G, T, C, A, and G. So if you notice the strand that is made is complementary to the template strand, and this is because of Bayes-Pearing rules. So you actually end up with two of these molecules. So it's this molecule times two. So what's important, if you look at your daughter molecules and you look at your parent molecule, they are identical. So as long as DNA replication occurs without errors, you're going to end up with two identical daughter molecules, so the first molecule. And this is how you can duplicate and hence transmit your information. So we just learned about briefly the overview of DNA replication. Now we're going to go into the actual process of how it happened.