DNA Replication (L12) Flashcards
What are some properties of Eukaryotic DNA Replication?
- multiple linear chromosomes
- multiple origins of replication (to form replication bubbles)
- bidirectional
What does it mean by DNA replication is semi-discontinuous?
Half is replicated continuously and half is replicated dis continuously.
- leading strand synthesised continuously in 5’-3’
- lagging strand synthesised dis continuously in 3’-5’
What is the lagging strand synthesised as?
Okazaki fragments
An enzyme that makes an RNA primer, which starts DNA polymerisation.
Primate
Enzyme that synthesises a new DNA strand by adding nucleotide bases to parental template strands.
- only makes DNA in 5’-3’ direction
- cannot bind to single stranded DNA and start copying it
DNA Polymerase III
What are other functions of DNA Polymerase III?
- removes single strand binding proteins
- to prevent single strand nucleotides from being consumed by enzymes/be degraded.
This enzyme forms the replication fork
Helicase
Enzyme that works alongside helicase to loosen tension between twisted strands. This cuts the strand and glues them back together
Tropoisomerase
This joins newly synthesised Okazaki fragments together in the lagging strand — also creates phosphodiester bonds (because it’s the main bond for DNA)
DNA ligaments
This removes RNA primers and fills the gap with DNA nucleotides. (Has two functions) This uses the 3’ OH group to extend it all the way to 5’ phosphate group to do this.
DNA Polymerase I
What is the function of nuclease?
They chop/remove nucleotide sequences to repair DNA errors.
This removes error during DNA replication
Exonuclease
This removes error after DNA replication.
Endonuclease.
What is DNA Replication in Vitro? What components are involved in this process?
Basically the artificial making of DNA to work/study with. Molecular Photocopying
Is composed of DNA template, Primers, DNA polymerase, and dNTPs
Are free nucleotides used as building blocks by DNA polymerase in in vitro DNA replication.
dNTPs
