Chapter 13 Flashcards
Which way does replication occur?
Bidirectionally
Where does replication start?
At origin site
Replication forks are sites where:
- parental ds DNA helix is unwinding
- nucleotides are incorporated into newly strands
What can relieve supercoiling?
DNA gyrase
Does DNA gyrase use ATP?
Yes
How does DNA gyrase work?
It travels in front of the replication form, creating ds DNA breaks and sealing them
What is the responsibility of DNA polymerase?
Synthesizing new DNA strands from DNA template
Which direction does DNA polymerase occur in?
5 to 3
What does DNA polymerase require?
A primer
In semi discontinuous replication, which daughter strand are synthesized first?
They are simultaneously synthesized
Leading strand synthesis:
Synthesized continuously
Lagging strand synthesis:
Synthesized discontinuously
What is the major enzyme responsible for DNA replication?
DNA Pol III
What is a primase?
An RNA pol that assembles short RNA primers
How are the strands sealed in replication?
DNA ligase
What is the purpose of a helicase?
Unwinds the parental strands
DNA pol III function in DNA replication:
Synthesize successive fragments of lagging strand
DNA pol I function in DNA replication:
DNA repair, removes RNA primers and replaces them with DNA
What do exonucleases do in DNA replication?
Degrade nucleic acids by removing 5 to 3 terminal nucleotides
What are replicons?
Replicate genome in small portions
What are the 5 polymerases?
a, b, g, d, e
g polymerase function
Replicates mtDNA
b polymerase function
Involved in DNA repair
a polymerase function
Initiates Okazaki fragment synthesis
d polymerase function
Lagging strand synthesis
e polymerase function
leading strand synthesis
What are 3 ways cells can DNA repair?
- nucleotide excision repair
- base excision repair
- mismatch
What is mitosis?
Leads to production of cells that are genetically identical to their parent cell
What is meiosis?
Leads to production of cells with half genetic content of parent cell
