How DNA replication works?
DNA replication is semi-conservative as the strands produced as a result always have one of the original strands that has been used to make it. During DNA replication the enzyme DNA helicase unwinds and ‘unzips’ the double strands that make up DNA by breaking the hydrogen bonds that join the bases. This then leaves free exposed bases for the enzyme DNA polymerase to add complementary bases together following the base pairing rule (A with T, C with G). However, new nucleotides can only be added to the 3′ end, and the DNA strand grows in the 5′ –> 3′ direction, making a growing chain. This is known as the leading strand. Okazaki fragments however make up the lagging strand because replication can only be performed in the 5′ –> 3′ direction. This therefore means that the strand elongates instead of continuously growing as the leading strand does. The enzyme that catalyses this is DNA ligase, connecting the Okazaki fragments together. These two strands are anti-parallel as one will be 5′
