Molecular Bio

Fall25

Primase Role

synthesizes RNA primer, provides 3’OH next to ssDNA for DNA synthesis

Primase Location

near replication fork on both leading and lagging strands

DNA polymerase I Role

removes RNA primer and fills gap left from primer

DNA polymerase I Location

in 3’ DNA polymerase direction of Pol3

only in the lagging strand, as it isn’t involved in replication but primer removal 

DNA ligase Role

seals ssDNA nick left after primer removal and fills in b dNAPol

dNA Ligase Location

on lagging strand, towards 5’ end of synthesis 

ddNTP

can SN2 attack but not bp, terminating nucleotides for Sanger

NGS

done via ligatation on known sequence to molecule = primers, can be used to sequence any type of DNA

Origin in Euk

AT rich dt easier seperation

ORC

origin recognition complex; binds to ARS in dNAsel footprinting assa, ATP dep

CCK and ddK

when high trigger dNA replication

Cdt1

present in G1 only so helicase, loads onto origin

Geminin

keeps helicase off newly replicated origins; destroyed in M phase