Lecture 13: DNA Replication Flashcards
Which way is DNA ALWAYS synthesized
5’ → 3’
What does DNA being anti parallel mean (remember which way DNA is synthesized)
the parental DNA strand runs 3’ to 5’
How many chromosomes in humans
23
What bases are prevalent at origins of replication
origins of replication are AT rich regions
What enzyme unwinds DNA
Helicase
DNA replication as a process is…
semi-discontinuous this is as the lagging strand is synthesized discontinuously while the leading strand is not
What strand is continuously synthesized
the leading strand
What enzyme recruits Helicase to initiate RNA synthesis
RNA polymerase 2
What is primase
An enzyme, a type of RNA polymerase, that makes an RNA
primer.
Primer will act as a starting point for DNA polymerization
What is DNA polymerase III
Enzyme that synthesizes a new DNA Direction of replication strand by adding nucleotides complementary to the parental
template strands
Only makes DNA in the 5’ to 3’ direction
What prevents DNA from re-joining in replication
Single strand binding proteins
What does DNA Pol I do
Two activities: Removes RNA primers
(RNase H) and fills the gap with DNA
nucleotides (DNA polymerase)
What does DNA Ligase do
Joins the newly synthesized Okazaki
fragments together (creates
phosphodiester bonds)
What is Polymerase Chain Reaction (PCR)
DNA replication in a test tube
A laboratory technique used to
make millions to billions of copies of
a particular section of DNA from a
very small original amount, which
can then be studied in greater
detail.
What are the two types of DNA error repairs
DURING replication using an EXOnuclease
AFTER replication using an ENDOnuclease
What enzyme is in charge of DNA error repair DURING replication
DNA pol III
DNA pol III has a proofreading mechanism:
Checks the newly inserted nucleotide bases against the
template
What are some things that could cause DNA damage or error
Incorrectly inserted bases are not corrected by DNA pol III
Radiation damage (e.g. UV)
Chemical modifications of bases (natural & chemical causes)
What is the difference between before and during replication repair
After replication is less specific, endonuclease takes away the error AND flanking reigons
