Science
How does DNA replicate?
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.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how DNA works.
Step by step
- 1The double helix unzips into two single strands.
- 2Each strand serves as a template for a new partner strand.
- 3Bases pair by the rules (A–T, G–C), copied by enzymes.
- 4You end with two identical DNA molecules, ready for cell division.
Frequently asked questions
- 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.