dna replication 5 Flashcards
what are the 4 molecules both prokaryotes and eukaryotes use
helicases
ssbs
rna primers
dna polymerases
where does eukaryotic dna replication occur
in the nucleus
what’s the 4 differences between prokaryotic and eukaryotic replication
more genetic material
more than one chromosome
linear chromosomes
additional packaging
how many points of origin do eukaryotes have per chromosome
10-1000s
are prokaryotic or eukaryotic polymerases slower and what is eukaryotic polymerases speed
eukaryotic
1000 nt/ sec
what do eukaryotic dna polymerasesnot contain
5’-3’ exonuclease
which have longer Okazaki fragments; eukaryotic or prokaryotic
prokaryotic
what is the origin of replication called in eukaryotes and what is the region rich in
autonomously replication sequences
rich in AT
in what phase of the cell cycle does initiation occur in
the G1 phase
what initiates the whole process of replication
binding of OCR to the dna
during the G1 phase what accumulate in the nucleus and what specific proteins will bind to the OCR
licensing factors
cdc-1 and cdt-1 will bind to the OCR
what is the function of cdc-1
loading helicase onto the dna
what phase doe activation happen in
s phase
what is added to helicase to activate it and what is this complex called
additional proteins and dna polymerases
- the complex is called the replisome progression complex
what is passive replication
when one replication fork passes through a region with a point of origin in it, without activating it
what are 3 features of polymerase a
- it is self-priming
- it cannot proofread
- it does not associate with PCNA
what loads pcna onto the dna
replication factor c
what does polymerase b do
repair
what does polymerase y do
replication of mtDNA
what does polymerase o do
works on the lagging stand
what does polymerase e do
works on the leading strand
how do polymerase o and e deal with rna primers
they create an rna flap, where the DNA is hanging off and rnase h1 will digest it but will leave one nt of rna
what removes the final nt of rna/ any incorrect dna
flap 1 endonuclease
where are telomeres located and why are they important for the chromosome
at the end of the chromosome
they are important as where rna primers are placed and removed, gene shrinkage can occur
telomeres act as a non important region so it wont matter if it is lost
what is the hayflick limit
where all the telomeric dna has been used, and important genes will begin to be lost
how can we overcome the hayflick limit and what protein is used for this
synthesise more telomeric dna
telomerase
how does telomerase work and what type of protein is it
it works by acting as a template, so pol a will continue to extend it
ribonucleoprotein
what is the lagging strand in mtdna made of
rna okazaki fragments
what is 2 features of mtdna replication
-circular
-unidirectional
what mechanism do bacteriophages use for replication
rolling circle mechanism
what do rna genomes use to replicate and what are 2 features about it
rna replicase
-self priming, no proof reading
how do retroviruses create dna strands and what enzyme do they use
they create a dna strand from rna template, then degrade the rna half, and create the other DNA strand from the first DNA strand
(hard to make sound right soz)
they kinda just make a dna-rna hybrid and then get rid of the rna side and make just a full DNA
reverse transcriptase
