DNA REPLICATION Flashcards
Is the synthesis of a new DNA
molecule from an existing DNA molecule
DNA Replication
What are the 3 DNA REPLCATION HYPOTHESIS
-the semiconservative model
- the conservative model
- the dispersive model
two DNA copies are
produced from one original
DNA, which serves as a
template
Outcome: One molecule
would be entirely parental
DNA, and the other would be
entirely new DNA
Conservative
-the two strands of DNA
unwind from each other, and
each acts as synthesis a
template for of a complementary strand new
-Each new DNA molecule
consists of one original
(parental) strand and one
newly synthesized strand
Semi Conservative
DNA replication results in two DNA
molecules that are mixtures, or “hybrids,” of parental and daughter
DNA
The parental DNA is randomly
broken into fragments, and the
new DNA is interspersed
throughout
Dispersive
used equilibrium density gradient
centrifugation experiments to demonstrate that DNA replication is semiconservative
Matthew Messelson and Franklin Stahl
DNA replication can be divided
into three phases:
-Initiation
-Elongation
-Termination
It is called the origins of replication and moves away from an origin in both directions, creating a structure that known as a replication bubble.
Initiation
It initiate proteins to bind to the replication origin, wherein a base pair sequence of nucleotides known as???
Oric
When replication DNA begins, These site reffered to as??
Replication Forks
An enzyme unwinds the double helix and exposes each of the two strands.
DNA helicase
It synthesizes a small RNA primer, in which acts as a kick starter for DNA polymerase
DNA Primase
It prevents the DNA double helix ahead of the replication from tight wounding as the helicase help to open up the DNA
Topoisomerase
In what formation wherein it able to extend the primer by adding a free nucleotides to the 3’ end new strand formed in a 5’ to 3’ direction
Leading strand
It occurs to the RNA primers that are added to the newly exposed bases on the fragments but it still occurs in the 5’ to 3’ direction as before?
Lagging strand
either no more DNA template strand left to replicate (i.e. at the end of the chromosome) or two replication forks subsequently
Termination
It removes all RNA primers in the lagging strand
Exonuclease
What type of enzyme that open ups the DNA at the replication fork
Helicase
What type of an enzyme that coat the DNA around the replication fork to prevent rewinding of the DNA
Single stranded binding proteins
What type of enzyme that is complementary to the DNA strand
Primase synthesizes
What type of an enzyme extends the primers, adding on the 3’ end, to make the bulk of the new DNA.
DNA polymerase III
What type of an enzyme that are removed and replaced with the DNA by DNA polymerase I
RNA primers
What type of a enzyme that gaps between DNA fragments that are sealed of?
DNA Ligase
