2. DNA Replication

3. Replication: The process before a cell divides, it duplicates and copies its DNA. DNA  DNA Remember: Each strand can be used to make the other strand, the strands are said to be complementary.

4. The Replication Process Replication occurs in late interphase of the cell cycle. During Replication DNA molecule separates or unzip into two strands which serve as a template Produces two new complementary strands following the base pairing rule

6. The Role of Enzymes in Replication Enzymes aid in: - “unzipping” DNA molecule by breaking the hydrogen bonds. - “zipping” DNA molecule back together. Enzymes involved in Replication Helicase: An Enzyme that unzips the DNA into two strands. DNA polymerase: An enzyme that joins individual nucleotides to produce a new strand of DNA. Also “proofreads” each new DNA strand.

7. Other Enzymes Used in Replication Telomeres- DNA at the tips of chromosomes. (difficult to replicate) Telomerase: Add short, repeated DNA sequences to the telomeres. Help prevent genes from being damaged or lost during replication. Involved in aging.

9. Prokaryote Replication Prokaryote have a single, circular DNA. Replication Starts when regulatory protein binds Starts at a single point and proceeds in two directions until entire chromosome is copied

10. Eukaryotic Replication Eukaryotic chromosomes are much larger than prokaryotes. Replication May begin at dozen or even hundreds of places on DNA Proceeds in both directions until each chromosome is copied.

11. DNA Replication Review