Ch DNA Replication

Target #15- I can describe DNA replication A single DNA strand can serve as a template for a new strand –Replication: the process by which DNA is copied during the cell cycle Process allows for accurate duplication Assures that every cell has a complete set of identical genetic information –Process is fast About 50 nucleotides are added every second to a new strand of DNA Occurs at multiple locations on each strand to allow for maximum replication speed

Target #16- I can identify the role that enzymes and proteins play in DNA replication Enzymes and proteins are involved with the replication –Enzymes called helicases starts the process by “unzipping” the double helix into two strands Location the DNA splits is called the replication fork –Proteins hold the strands apart –Free-floating nucleotides are attached to the existing strands by the enzyme DNA polymerase

Target #17- I can explain the role DNA polymerase has in the replication of DNA DNA Polymerase: a group of enzymes that bond the new nucleotides together Also acts as the proof- reader during replication –If the wrong nucleotide is added to the strand, DNA polymerase can detect it, remove the error, and replace it with the correct one

Target #18- I can describe the steps of DNA replication Step 1 –DNA helicase “unzips” the DNA strand Nucleotide base pairs are separated –Replication begins on both strands of the molecule at the same time

Target #18- cont Step 2 –Each existing strand of DNA is a template for a new strand –Free floating nucleotides pair-up with the exposed bases on each template strand –DNA polymerases bond the nucleotides together to form the new strands

Target #18- cont Step 3 –Two identical DNA double helixes are produced –Each new double helix is half the original strand and half the new strand