1. KEY CONCEPT DNA replication copies the genetic information of a cell.

2. Replication copies the genetic information.
A single strand of DNA serves as a template for a new strand.
The rules of base pairing direct replication.
DNA is replicated during the S (synthesis) stage of the cell cycle.
Each body cell gets a complete set of identical DNA.

3. Helicase: unzip the DNA and separate the nucleotides of the two strands
DNA polymerase:
Ligase: bond together the nucleotides after the replication

4. Proteins carry out the process of replication.
DNA serves only as a template.
Enzymes and other proteins do the actual work of replication.
Helicase unwind and unzip the double helix.

5. Unwind

6. Unzip

7. DNA unwinding and unzipping process

8. Proteins carry out the process of replication.
Free-floating nucleotides form hydrogen bonds with the template strand.
nucleotide
The DNA molecule unzips in both directions.

9. DNA polymerase enzymes bond the nucleotides together to form the double helix.
Polymerase enzymes (ligase) form covalent bonds between nucleotides in the new strand.
DNA polymerase
new strand
nucleotide

10. Leading and lagging strands
Leading strand: it is going to replicate continously
Lagging strand: it is going to replicate by patches.

11. DNA replication is semiconservative.
Two new molecules of DNA are formed, each with an original strand and a newly formed strand.
DNA replication is semiconservative.
original strand
new strand
Two molecules of DNA

12. Replication is fast and accurate.
DNA replication starts at many points in eukaryotic chromosomes.
There are many origins of replication in eukaryotic chromosomes.
DNA polymerases can find and correct errors.