DNA Replication PDF

## DNA Replication **DNA Replication** - Both Eukaryotes and prokaryotes have DNA replication. - Eukaryotes - Inside nucleus **When:** - Before cell division - During interphase Daughter cell can have DNA copy. **Key Component: Enzyme** - Ends in *ase* - Most likely an enzyme. - Protein that...

## DNA Replication **DNA Replication** - Both Eukaryotes and prokaryotes have DNA replication. - Eukaryotes - Inside nucleus **When:** - Before cell division - During interphase Daughter cell can have DNA copy. **Key Component: Enzyme** - Ends in *ase* - Most likely an enzyme. - Protein that helps speed up metabolism/chemical reactions in the body. - Build up substances and break down others. **Where:** - Starts in *origin*. - Has certain DNA sequences. ## Key Components **Helicase:** “unzipping enzyme” - “Unzips” the two DNA strands. - Breaks hydrogen bonds that hold DNA bases together. **SSB Proteins** keep strands separated. **Topolsomerase** keeps the rest of DNA from supercoiling. **Primase:** “Instructor” - Director of where DNA polymerase is to build. - Create building blocks for DNA by making primers (made of RNA). **DNA Polymerase:** “builder” - Copies DNA molecules to create new strands of DNA. - Can only move in 5’-3’ direction, but still go opposite directions. ## Leading vs. Lagging Strand **Leading Strand:** Builds new strands in the 5’-3’ direction and adds new bases to the 3’ end of the new strand. **Lagging Strand:** Builds new strand in the 5’-3’ direction, but starts at the new strand and goes to the base. ## Primers and Ligase - Primers have to keep being placed to show the lagging strand where to go. - Create fragments: **Okazaki fragments**. - **Ligase** comes in and has to fill in these spaces. - **Ligase:** “gluer” - Gives DNA fragments together.