3.3 - DNA Replication Flashcards
What is the name of the enzyme that unwinds a DNA double helix to prep it for replication?
Gyrase or topoisomerase
What does gyrase do?
also known as topoisomerase
unwinds DNA
What is the name of the enzyme that creates the DNA replication fork?
Helicase
Think wedge, pushing a part strands
What is the purpose of helicase?
unzips the 2 DNA strands
and
breaks the hydrogen bonds
What stops seperated DNA strands from re-coiling together?
single stranded binding proteins
SSBP
What’s the purpose of SSBP?
- holds the DNA strands straight
- stops both strand from rejoining
- stablizes replication fork
3.3
What adds primers in replicating DNA?
RNA polymerase
aka
primase
What’s the purpose of RNA primers?
adds primers for new DNA strands to be built off of
What enzyme adds nucleotides?
DNA polymerase III
What’s the purpose of DNA polymerase III
to add nucleotides
What enzyme removes primers?
DNA polymerase I
What’s the purpose of DNA polymerase I?
- remove RNA primers & replace it with DNA
- however cannot connect okazaki fragments
What enzymes forms bonds between Okazaki fragments?
DNA ligase
Think lag as in lagging strand
What’s the purpose of DNA ligase?
Think lag as in lagging strand
To form phosphodiester bonds between Okazaki fragments
What is the 8th and final step of DNA replication?
When the copy strand is complete, it twists back into a double helix to form new DNA
