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State the characteristic of DNA replication

• It is semi-conservative

Outline DNA replication

1. Double helix unwinds
2. Separation of the strands by helicase
3. Formation of the new complementary strands by DNA polymerase

In DNA replication, the 2 chains separate from each other like a zip unfastening as the hydrogen bonds, which link the bases of one chain with the bases of the other, are not very strong. Any free nucleotides then come along and form hydrogen bonds with each of the 2 chains. These nucleotides then join together through their sugar and phosphate groups; and 2 DNA molecules result. The complementary relationship between the bases ensure that each of the DNA molecules are identical to the original one. Because the sequence of the bases in the 2 daughter molecules is exactly the same in the parent molecule (i.e. A to T and C to G), accurate replication occurs. The enzyme that joins the nucleotides together is called DNA polymerase.

Explain the significance of complementary base pairing in the conservation sequence of the base sequence of DNA

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