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DNA replication

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jisodeve's version from 2017-01-04 20:23

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Question Answer
DNA structureDouble helix (2strands of DNA); complementary strands pair up via hydrogen bonds, Strands are antiparallel
What is attached to the 5' Carbona phosphate
What is attached to the 3' carbonan OH
The antiparallel nature of double stranded DNA meansthe two strands run from 5' to 3' in oppossite directions; the 5' ends of the two strands are on the oppossite end of the DNA molecule
When is DNA copied?during the S phase
When does Mitosis occurG2
when does the cell size normalize?G1
How do you create a new strand? by matching nucleotides to an existing strand
DNA replication Replication is semi-conservative (one strand is old, one strand is new)
Where does DNA replication startat the origin of replication
Origins of replication located every _____basepaires100,000
General Process of DNA replication1. initiator proteins, the ORC bind to origins of replication to begin replication 2. DNA Helicase separates the DNA helix, Topoisomerase prevents supercoiling. single stranded binding proteins prevent double helix from reforming 4. DNA polymerases gamma and epsilon build the new strand of DNA in a 5' to 3' direction
ORCattracts other enzymes involved in replication process including (Cdc6p, MCM, )
Cdc6preplication activator protein
MCMmini chromosome maintenance known as helicase
What must happen to ORC, Cdc6p, and MCM in order for DNA replication to startORC, Cdc6p, MCM must be phosphorylated
What do Cdc6 and Cdt1 proteins do to MCMthey load the hexameric MCM helicase to form the "licensed" pre-RC in G1 phase
Geminininhibits Cdt1 and pre-RC formation
When do CDK and DDK become activein late G1
What do CDK and DDK do they activate the MCM helicase and load on the replisome that contains the DNA polymerase
How does CDK inhibit licensingby phosphorylating Sld2 and Sld3
DDK inhibits licensing bythe phosphorylation of the MCM proteins
DNA helicaseseparates the DNA helix
Topoisomeraseprevents overwinding of DNA
Single Stranded binding proteinsprevent double helix from reforming temporarily
Positive supercoils are caused bythe unwinding the DNA
Positive supercoiledmore than 10.4 bp occur in a turn
Negatively supercoiledless than 10.4 bp per turn
What do topoisomerases dothey cut the DNA to prevent from supercoils, they let the DNA unwind; then reseal the DNA
Topoisomerase 1 cuts only 1 strand of DNA
Topo 1 inhibitorCamptothecin (used to treat cancer)
Topoisomerase 2cuts both strands
Etoposideinhibits type 2 topoisomerase and used to treat cancer
DNA polymerase alphabuilds a RNA primer starting from 5' end of the new DNA strand
DNA polymerase alpha is composed ofRNA polymerase and a DNA polymerase
In order for DNA polymerase gamma and epsilon to polymerize a nucleotide they need3' OH
T/F DNA polymerase has no proofreadingTrue
DNA polymerase epsilon polymerizesthe leading strand
DNA polymerase Gamma Polymerizesthe lagging strand
PCNAproliferating cell nuclear antigen beta sliding clamp
If PCNA is upregulated then that meansthey may have cancer
What does PCNA dokeeps the DNA polymerase on the DNA
The leading strand is made goingtowards the replication fork
Replication away from the forkLagging strand
When does DNA polemerase gamma stop polymerizingwhen it meets an RNA primer
Rnase H and Fen 1Remove the RNA nucleotides
DNA ligaseforms a bond between newest DNA and adjacent Okazaki fragments
What kind of bond is made when sealing Okazaki Fragmentsphosphodiester.
What is a telomerea tandem repeat of TTAGGG at the end of a chromosome
Telomerasea specific enzyme with integrated RNA template
What kind of enzyme is a telomeraseidk find out
What is telomerase thought to preventaging
memorize