![]() The replication of the lagging strand DNA is more complicated in comparison to the leading strand due to its orientation. Lagging strand: The strand of the nascent DNA that gets synthesized in the opposite direction as the direction of the replication fork growth is the lagging strand. This is a continuous form of DNA replication. Leading strand: The strand of the nascent DNA that gets synthesized in the same direction as the direction of the replication fork growth is the leading strand. One major issue comes during the synthesis of nascent/new lagging strand DNA whose synthesis direction is opposite to the direction of replication fork growth, from the fact that the lagging and leading strand templates are aligned in directions opposite to each other at the replication fork. Hence, the nascent strand gets synthesized in the 5' to 3' direction. In order to read a DNA, the DNA polymerase is read in 3′ to 5′ direction. These two strands are called the lagging strand template and the leading strand template. When the DNA polymerase matches with its complementary nucleotides, these two strands act as the template for the lagging and leading strands. Each of these prongs is composed of a single strand of DNA. There are two branching “prongs” in the structure of the replication fork. The replication fork is the area exposed by the DNA helicase, as it looks like a fork in the road. These bases, then, are used during the replication of DNA as the template. To open the DNA, DNA helicase is needed, which exposes the nucleotide bases. The shape of the DNA in normal circumstances looks like a winding staircase.ĭNA cannot be copied in its normal form. When the DNA is not being copied, it is double-helix shaped. The human DNA is double-stranded, with hydrogen bonds holding the two strands together. For the replication machinery to generate a copy of the DNA, the DNA needs to be in the correct orientation to be duplicated. Just before the cell splits for the formation of two new cells, a copy of DNA is created. Due to this reason, except for the red blood cells, every cell of the human body needs a copy of the DNA. Figure: Replication Fork Scheme: template (a), leading strand (b), lagging strand (c), replication fork (d), primer (e), Okazaki fragments (f)ĭNA contains all the information about a human being.
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