15. What is accomplished when ATP is hydrolyzed by DnaA? a) Allows formation of
ID: 213543 • Letter: 1
Question
15. What is accomplished when ATP is hydrolyzed by DnaA?
a) Allows formation of the oriC/DnaA complex
b) Allows DnaA to unwind DNA
c) Inacti vates the DnaA for replication initiation
d) Removes DnaA at termination of replication
e) Helps bind DnaB helicase to the clamp
16. What is accomplished when ATP is hydrolyzed by DnaC?
a) Allows formation of the oriC/DnaB complex
b) Helps release DnaB helicase as it is loaded onto the DNA
c) Helps bind DnaB helicase to the [3 clamp
d) Removes DnaC at termination of repl ication
e) Removes DnaA at termination of replication
17. When a replication error is detected:
a) the tilispaired nucleotide is removed by a condensation reaction, releasing a water.
b) the mispaired 3' terminus frays by four nucleotides to allow it to be inserted into the 3 1 -5' exonuclease site.
c) the —OH group on a tyrosine acts as a nucleophile to remove the incorrect base.
d) the 5 1 -3' exonuclease site uses acidic amino acids to catalyze nucleotide removal.
e) all of the above are correct.
1 8. Universal features of DNA polymerases include:
a) 5'-3' exonuclease function.
b) Formation of an 'closed' conformation of the polymerase when the template-nucleotide base pair is correct.
c) Use of a single magnesium ion to orient reacting molecules and assist in dissipation of the negative charge that develops during nucleotidyl transfer.
d) Alignment of conserved residues in the active site for attack of the DNA primer by the 3'OH on the incoming nucleotide.
e) Continuous unbinding and rebinding of the polymerase to the DNA template as each nucleotide is added.
19. Which of the following is FALSE of the trombone model of replication?
a) As Okazaki fragments are extended by POI Ill , the loop in the DNA template grows.
b) Once an Okazaki fragment is completed, the (3 clamp is ejected.
c) A loop is formed in one strand of the template DNA to allow 5 1-3' synthesis of the lagging strand.
d) When a new [3 clamp is loaded, primase is triggered to synthesize a primer.
e) Binding of the polymerase core to a new primer/template complex occurs after loading of the (3 clamp.
20. What function does helicase perform during replication?
a) It stabilizes the negative charge of the transition state.
b) It utilizes ATP to power DNA strand separation.
c) It adds negative supercoils to DNA.
d) Both A and C are correct.
e) None of the above.
Explanation / Answer
15} Answer C.
DnaA is a enzyme which initiates DNA replication. It has a great affinity for Atp and is highly active when bound with Atp molecules. When the DnaA-Atp hydrolysis takes place it gets attached to Adp and becomes inactive bringing down the levels of DNAA-Atp thus initiating the replication process . The hydrolysis releases required energy for the process.
16] c.
DnaB is the enzyme required for Dna replication to start . Dnac Hydrolyses the Atp and helps the helicase to attach to the clamp where the unwinding process starts.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.