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greenmacaw965Lv1

28 Sep 2019

Can methylation of nucleotides play a role in DNA replication?

If so, what role does it play?

Removal of methyl groups from nucleotides is concurrent with the conversion of dNTPs to dNMPs during DNA synthesis.

Lack of methylation on the synthesized DNA strand can be recognized by repair enzymes, thus permitting selective base pair mismatch repair.

Lack of methylation on the parental DNA strand can be recognized by repair enzymes, thus permitting selective base pair mismatch repair on the newly synthesized strand.

Methylation does not play a role in replication.

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lalithashwin156Lv10

7 May 2023

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28 Sep 2019

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Related questions

What are the advantages of recombination? What are the disadvantages? Under what kinds of ecological conditions (stable environment, high predation rates, exposure to rapidly evolving parasites, etc.) would you expect to favor one, or the other?

Suppose you found a region of a genome in a vertebrate that was quite large (say, 10 million base pairs) that had an extremely low recombination rate. Suggest a reason why it might be advantageous to not recombine the genes in that genomic region.

How do prokaryotes distinguish the newly synthesized strand from the old template strand? Why donât eukaryotes use the same mechanism?

What is methylation used for in prokaryotes? In eukaryotes?

What happens if mismatch repair occurs shortly after replication? How does it know which mismatched, normal base is incorrect? What happens if mismatch repair occurs long after replication has occurred?

Why does uracil DNA glycosylase have so an easier task to perform than thymine DNA glycosylase?

Describe the steps that occur following uracil DNA glycosylase activity. What needs to happen; what enzymes are involved?

What do x-rays do to DNA? What does UV radiation do? What do microwaves do?

Is there a safe minimum dose of radiation?

Why is telomerase turned off in human somatic cells? Is it turned off in mouse somatic cells? Would you expect it to be turned off in elephants? Would you expect elephants to have high cancer rates compared to mice?

Where is telomerase necessary? Is it on the leading, or lagging strand, or both? Why donât bacteria need telomerase?

Why is microsatellite instability used by physicians to measure problems with mismatch repair?

2. Which of the following does not involve gap repair?

Question 2 options:

insertion (i.e. "paste") of a DNA transposon

base excision repair

two of the above

proofreading by DNA polymerase delta

nucleotide excision repair

3. Which of the following DNA repair mechanisms relies on differentiating the parental and daughter strands immediately after DNA replication?

Question 3 options:

mismatch excision repair

base excision repair

two of the above

error-prone double-stranded break repair by end joining

nucleotide excision repair

4. Reverse transcriptase has which common feature(s) with DNA polymerase alpha?

Question 4 options:

	can only use DNA as a template
	does not require a primer
	incorporates dNTPs
	synthesis occurs 3' to 5'
	all of the above

1.When a protein binds to DNA at a site defined by a particular nucleotide sequence, with which parts of the DNA does the protein primarily interact?

A. the phosphate and deoxyribose groups in the DNA backbone

B. the phosphate and deoxyribose groups in the DNA backbone, and hydrophobic interactions with the nucleotide bases

C. nucleotide bases within the major grooves of the DNA

D. nucleotide bases within the major and minor grooves of the DNA

E. none of the above

2. Which of the following proteins binds to DNA with sequence specificity?

A. POI Ill holoenzyme

B. DnaA

C. DnaB

D. Dam methylase

E. Both B and D

3. Which of the following is NOT a functional parallel among all known cellular systems of DNA replication?

A. Replication is initiated at specific sites

B. Replication is continuous on the leading strand and discontinuous on the lagging strand

C. DNA replication is semiconservative

D. Replication forks move away from the origin in one direction

E. Nucleases, polymerases and ligases replace RNA primers with DNA and seal the remaining nick

4. A DNA polymerase cannot synthesize a DNA strand de novo (from the beginning) from a mixture of dNTPs. Which of the following explains the role of the primer in the reaction promoted by this enzyme?

A. The primer is an initiation protein with attached nucleotides that binds to the template and to which new nucleotides are added to the 3 ' end.

B. The primer is an initiation protein with attached nucleotides that binds to the template and to which new nucleotides are added to the 5' end.

C. The primer is a preexisting strand of RNA or DNA to which new nucleotides are added to the 3' end.

D. The primer is a preexisting strand of RNA or DNA to which new nucleotides are added to the 5' end.

E. The primer is a preexisting strand of DNA synthesized by DNA pol I, prior to replicative DNA synthesis by DNA pol Ill.

5. 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.