What does DNA Polymerase I do & what type of cell is it found in?
DNA synthesis; 3' to 5' exonuclease (for proofreading); 5' to 3' exonuclease; removes and replaces RNA primers used in DNA replication (also functions in excision repair of damaged DNA).
Bacteria Cells
What does DNA Polymerase III do & what type of cell is it found in?
DNA synthesis; 3' to 5' exonuclease (for proofreading); used in synthesis of both DNA strands
Bacteria Cells
What does DNA Polymerase alpha do & what type of cell is it found in?
Nuclear DNA synthesis; forms complex with primase and begins DNA synthesis at the 3' end of RNA primers for both leading and lagging strands (also functions in DNA repair).
Eukaryotes
What does DNA Polymerase gamma do & what type of cell is it found in?
Mitochondrial DNA synthesis
Eukaryotes
What does DNA Polymerase delta do & what type of cell is it found in?
Nuclear DNA synthesis; 3' to 5' exonuclease (for proofreading); involved in lagging and leading strand synthesis (also functions in DNA repair). They think DNA Pol epsilon does the same thing.
Eukaryotes
What does Primase do & what type of cell is it found in?
RNA synthesis; makes RNA oligonucleotides that are used as primers for DNA synthesis
Both Eukaryotes and Bacteria
What does DNA helicase do & what type of cell is it found in?
Unwinds double-stranded DNA
Both Eukaryotes and Bacteria
What does Single-stranded DNA binding protein (SSB) do & what type of cell is it found in?
Binds to single-stranded DNA; stabilizes strands of unwound DNA in an extended configuration that facilitates access by other proteins.
Both Eukaryotes and Bacteria
What does DNA ligase do & what type of cell is it found in?
Makes covalent bonds to join together adjacent DNA strands, including the okazaki fragments in lagging strand DNA synthesis and the new and old DNA segments in excision repair of DNA.
Both Eukaryotes and Bacteria
What does an initiator proteinn do & what type of cell is it found in?
Bind to origin of replication and initiate unwinding of DNA double helix
Both Eukaryotes and Bacteria
What does telomerase do & what type of cell is it found in?
Using an integral RNA molecule as template, synthesizes DNA for extension of telomeres (repetitive sequence at the ends of chromosomal DNA)
Eukaryotes
What three things are required for DNA replication to occur?
1. DNA Polymerase
2. Primers
3. Nucleotides
What is an exonuclease?
Enzymes that degrade nucleic acids (usually DNA) from one end. Unlike endonucleases that make internal cuts.