8.3 DNA Replication

KEY CONCEPT General Description: DNA replication copies the genetic information of a cell.

8.3 DNA Replication

Replication copies the genetic information.

• A single strand of DNA serves as a template for a new strand.

• The rules of base pairing directreplication.

• DNA is replicated during theS (synthesis) stage of thecell cycle.

• Each body cell gets acomplete set ofidentical DNA.

8.3 DNA Replication

Proteins carry out the process of replication. • DNA serves only as a template. • Enzymes and other proteins do the actual work of

replication.• Process

1. Enzymes unzip the double helix. (DNA Helicase)2. Free-floating nucleotides form hydrogen bonds

with the template strand.nucleotide

The DNA molecule unzips in both directions.

8.3 DNA Replication

3. DNA polymerase enzymes bond the nucleotides together to form the double helix.

- DNA polymerases can find and correct errors.

3. DNA polymerase

4. new strand 2. Nucleotide

1. Sugar Phosphate Backbone

8.3 DNA Replication

• DNA replication is semi-conservative, meaning one original strand and one new strand.

original strand new strand

Two molecules of DNA

4. Two new molecules of DNA are formed, each with an original strand and a newly formed strand.

8.3 DNA Replication

There are many origins of replication in eukaryotic chromosomes.

• DNA replication starts at many points in eukaryotic chromosomes.

Replication is fast and accurate.

8.3 DNA Replication

How does replication conserve genetic information?

• Each parent or original strand of DNA serves as a template, allowing 2 identical strands of DNA to be made. This means the information “stays” the same or is “conserved”.

• https://www.youtube.com/watch?v=zdDkiRw1PdU

8.3 DNA Replication

• https://www.youtube.com/watch?v=z685FFqmrpo