BIO230W Exam 4 Flashcards
Will DNA at the origin be heterochromatic or euchromatic?
Chromatin must be remodeled to be euchromatic as opposed to heterochromatic
Describe the A-T, G-C base pairs at origins of replications
More AT base pairs compared to GC so easy to bind to and separate
What protein complex binds to the origin before helicase is loaded?
Origin Recognition Complex identifies and binds to origin (specific DNA region)
During which cell cycle stage is the full pre-replication complex bound to DNA?
G1
MCM
DNA modifying helicase (enzyme) that separates DNA strands at the origin
What three components make up the pre-replication complex (PRC?)
Origin recognition scaffold (ORC, cdt1, cdc6), helicase loader, helicase
How does the concentration of geminin relate to the ability of a cell to replicate its genome in this experiment?
Geminin and MCM helicases is loaded in G1, but not activated until S phase.
When is the MCM double helicase activated?
S phase
What is the role of geminin?
Blocks additional helicase loading during S-phase, G2 phase, and through mitosis
When is geminin active?
S, G2, and M
Why does geminin not block replication during S-phase?
Geminin prevents reloading of active MCM helicases after G1 by directly binding to cdt1. Geminin allows replication to occur b/c G1 was loaded before S-phase. prevents more replication than allocated in G1.
What would be the result if a cell lacked geminin?
80% of cells would successfully replicate
Which component of the replisome keeps separated strands of DNA from reannealing?
SSDBP (Single-stranded DNA binding protein)
How many replication forks are there in one replication bubble?
One bubble has two forks
What type of macromolecule is the primer for DNA polymerase?
proteinW
How many primers are present on the leading strand compared to the lagging strand?
Lagging strand has multiple primers (RNA), b/c it is done with okazaki fragments. leading strand only has 1 primer.
Describe processivity in relation to the action of DNA polymerase
The amount of catalytic cycles an enzyme can complete with a substrate without breaking
Direction of polymerization of transcription and replication
5’ to 3’
Direction that template is read of transcription and replication
3’ to 5’
Polymerizing enzyme of transcription
RNA polymerase
Polymerizing enzyme of replication
DNA polymerase
Template of transcription and replication
DNA
Increased processivity would cause
replication to be faster and more efficient b/c CLAMP proteins would not need to work to keep the enzyme and substrate together
3 steps of PCR
Denature, anneal and extend
PCR function
Amplifies a specific region of DNA by cycling 3 steps 30-40 times
What happens to the temperature in the PCR as it moves from the denature step to the annealing step?
Stays the same