DNA Replication Flashcards
Study for Genetics Exam 2
DNA Polymerase
Adds new nucleotides to 3’OH of daughter strand
Nucleoside Triphosphate
Three phosphate groups attached to a nucleotide
Phosphodiester Bond
Done by what enzyme?
3’ OH connects with 5’ monophosphate
Done by DNA ligase
Initiation
- Proteins bind to DNA and separate it into single strands
- Will serve as templates
- Then an enzyme synthesizes short RNA primer
Elongation
DNA polymerase uses template and 3’OH to add new nucleotides
DNA Polymerase III
DNA pol III
Primary enzyme for DNA synthesis
DNA Polymerase I
DNA pol I
Enzyme that removes RNA primers
DNA Helicase
Unwinds the double helix during replication
Single-stranded proteins
Keeps helix open
After helicase unwinds the double helix, the single strands are unstable
Primase
- Creates RNA primer
- Provides 3’OH groups for DNA pol III
Origin of Replication
Where a replication bubble will form
Dna A
Responsible for recognizing origin of replication and unwinding helix there
Bidirectional Replication
Replication goes in two opposite directions after replication bubble is formed
Leading Strand
- Only 1 primer needed for synthesis
- Synthesized by adding to 3’ end
- Synthesized in the same direction as the growing replication fork
Lagging Strand
- Multiple primers needed for synthesis
- Synthesized by adding to 5’ end
- Synthesized in short segments called Okazaki fragments
