What is dna replication

DNA carries the genetic information that codes for a particular protein. Thus, DNA molecules have to be replicated prior to cell division to ensure that the two cells after cell division will have the same genetic content.

In the early stages of mitosis prophase and meiosis prophase I , DNA is replicated in preparation for the late stages where the cell divides to give rise to two cells containing copies of DNA. Thus, after replication, the new DNA molecule will be checked through stringent proofreading and repair mechanisms. The point at which the strands separate is referred to as the replication fork replication fork is a Y-shaped region in a chromosome that serves as the growing site for dna replication.

To remain separated, single-stranded binding proteins will bind to these strands. The enzyme primase will then attach a primer a short fragment of RNA. In particular, adenine will pair with thymine while guanine with cytosine. DNA polymerases, though, can move in only one direction, i. Thus, one of the original DNA strands will allow the polymerase to move along the strand and add nucleotides continuously.

This strand is called the leading strand. The other strand, called the lagging strand , runs in the opposite direction. Thus, the polymerase in the lagging strand tends to create short fragments called Okazaki fragments that are later joined together by DNA ligase.

After the new strand is created, the primers are removed by RNAse H. When a cell divides, it must first duplicate its genome so that each daughter cell winds up with a complete set of chromosomes.

If you think about it, each cell contains all of the DNA you need to make the other cells. And we start out from a single cell and we end up with trillions of cells. And during that process of cell division, all of the information in a cell has to be copied, and it has to be copied perfectly. Open survey. In: Facts In the Cell. This is carried out by an enzyme called helicase which breaks the hydrogen bonds holding the complementary bases of DNA together A with T, C with G.

The two separated strands will act as templates for making the new strands of DNA. As a result of their different orientations, the two strands are replicated differently: An illustration to show replication of the leading and lagging strands of DNA. Related Content:. What is a genome? What is DNA?