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Dna Replication

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DNA Replication 1. DNA Replication take place by breaking the hydrogen bonds between bases of the two antiparallel strands. The unwinding of the two strands is the starting point. 2. Helicase (enzyme) splits the two strands. The initiation point, where the splitting starts, is called “origin of replication”. The structure that is created is known as “Replication Fork”. 3. Molecules of single-strand binding protein stabilize the unwound template strads. 4. Topoisomerase helps relieve the strain by breaking, swiveling, and rejoining DNA strands. 5. RNA Primase (enzyme) binds in the initiation point of the 3’ – 5’ parent chain. It can attract RNA nucleotides which bind to the DNA nucleotides of the 3’ – 5’ strand due to the hydrogen bonds between the bases. RNA nucleotides are the primers (starters) for the binding of DNA nucleotides. 6. DNA Polymerase III (enzyme) link up the free, matched nucleotide triphosphates by removing the terminal di-phosphate and using energy so released to carry out the very non-spontaneous chemical reaction of joining the phosphate to the deoxyribose sugar. 7. The strand that is synthesized continuously is called the leading strand and the strand that is synthesized in short pieces is called the lagging strand. The short pieces of synthesized DNA, which make up the lagging strand are called the Okazaki fragments. 8. Only one primer is required for DNA Polymerase III to synthesize the leading strand. 9. The lagging strand is the DNA strand of the replication fork, which is opposite to the leading strand. It is synthesized in the opposite direction, that is, 5' to 3' instead of the 3' end as in the leading strand. 10. Each Okazaki fragment on the lagging strand must be primed separately. After DNA polymerase III forms an Okazaki fragment, DNA polymerase I replaces the RNA nucleotides of the...

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