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Replication Fork

The replication fork is a structure that is formed when a DNA molecule replicates to form a new one. The two strands of DNA that are produced are identical copies of each other. In the process of replication, one DNA molecule produces two identical ones.

Midway through this process, a forklike structure is formed, which is known as the replication fork. Though DNA can duplicate through other methods too, the method of duplication via the replication fork is the most common.

During this process, a particular point on the DNA molecule becomes the point of origin, from where the entire process will begin. At this point, the DNA begins to break. This step is known as incision, which is controlled by endonuclease, an enzyme. The enzyme starts by breaking the hydrogen bonds that hold the strands together at the point of origin. The strand is now broken, and the process of replication begins.

Along the path, the hydrogen bonds keep breaking, and the two strands of the DNA molecule move apart. But, the whole DNA molecule does not separate at once; the strand opens in a Y-shaped manner. This is the structure that is defined as the replication fork.

dna replication

DNA Replication Fork

The structure of replication fork is important, because it takes the two threads apart. The nitrogen bases on the DNA molecule are now exposed. They pick up complementary nitrogen bases from the pool around them and form complete strands themselves. As the process continues, the entire DNA molecule start getting formed, and two new DNA strands are produced on the two that were present in the molecule.

A single DNA molecule consists of two strands that are shaped in a helical manner. These threads are in opposite direction to each other, known as the leading strand and lagging strand. At the replication fork stage, it is the leading and the lagging strands that are apart from each other.

The formation of the new DNA strand takes place easily on the leading strand because the new strand has to move in the same direction as the leading strand. But, on the lagging strand, the formation of the new strand takes place in fragments. These fragments are known as the Okazaki fragments, which are an important feature of the formation of DNA molecules through a replication fork structure.

replication fork

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