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How does DNA replicate?

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Quick answer

DNA replicates by unzipping its double helix into two strands, then building a matching new strand against each one using the base-pairing rules (A with T, G with C). The result is two identical copies, each with one old and one new strand.

Step by step

  1. The double helix unzips into two single strands.
  2. Each strand serves as a template for a new partner strand.
  3. Bases pair by the rules (A–T, G–C), copied by enzymes.
  4. You end with two identical DNA molecules, ready for cell division.

People also ask

Why does DNA need to replicate?
So each new cell gets a complete, identical copy of the genetic instructions when a cell divides.
What are the base-pairing rules?
Adenine pairs with thymine (A–T) and guanine with cytosine (G–C).
What enzyme copies DNA?
DNA polymerase builds the new strands; helicase unzips the helix first.