Genetics 2 Enzymes

origin of replication

location where replication begins

5’ to 3’

direction in which replication occurs

leading strand

strand created by continuous replication

lagging strand

strand created by discontinuous replication

leading strand template

parental DNA used as a template for the leading strand

lagging strand template

parental DNA used as a template for the lagging strand

Okazaki fragments

small pieces of DNA created by discontinous replication

gyrase

relieves tension due to supercoils caused by strand separation

helicase

unwinds the DNA double helix

primase

lays down the RNA primer since DNA polymerase requires a free 3’ OH

primer

small piece of RNA needed for DNA polymerase to begin replication

single stranded binding proteins (SSBP)

binds to the strands of DNA to keep them separated

DNA polymerase III

attaches to the primer & adds nucleotides

phosphodiester bonds

bonds joining nucleotides

DNA polymerase I

removes RNA primer & replaces it with DNA

ligase

seals the new strand by repairing the remaining nicks in the DNA