Molecular : Replication, mutation and DNA Repair
Explore DNA Dynamics: Replication, Mutation, and Repair
Test your knowledge on the fascinating processes of DNA replication, mutation, and repair! This quiz covers key concepts in molecular biology and is perfect for students, educators, and anyone interested in genetics.
- Multiple choice format
- Challenging questions on DNA mechanics
- Learn about essential enzymes and their fun
ctions
Which of the three models of DNA replication proposed that the original double helix remained entirely intact throughout the process?
Conservative model
Semiconservative model
Dispersive model
Destructive model
None of these.
Which statement about bacterial DNA replication is correct?
DNA replication begins at several places along the chromosome
DNA replication begins at the origin and travels in both directions.
DNA replication begins at the origin and travels around the chromosome back to the origin
DNA replication begins at a GC rich region of the chromosome.
All of these are correct.
Why is an AT rich region part of the E. Coli oriC?
DnaA proteins bind to AT rich sites.
DnaC proteins bind to AT rich sites.
AT base pairs are more easily separated than GC base pairs
AT base pairs contain more hydrogen bonds than GC base pairs
Which enzyme produces the first piece of nucleic acid synthesized in E. coli DNA replication?
DNA polymerase (polIII)
DNA primase
DNA polymerase (polI)
DNA ligase
What is a key difference between DNA polIII and DNA ligase?
Only DNA polIII synthesizes phosphoester bonds
Only DNA ligase synthesizes phosphoester bonds.
DNA polIII can synthesize DNA from 3'-5'.
DNA ligase can use energy from ATP rather than nucleotides
What is the major difference between the lagging and leading strands?
On the leading strand, DNA synthesis occurs from 5' to 3', while DNA synthesis occurs from 3' to 5' on the lagging strand.
DNA polymerase is able to continuously add new nucleotides on the leading strand while it must keep 'starting over' on the lagging strand.
The lagging strand requires only a single primer while the leading strand requires many
Helicase opens the leading strand at a faster rate than the lagging strand.
What explanation for Okazaki fragments is the most accurate?
DNA polymerase is only able to synthesize 1000-2000 bonds before it falls off the strand.
DNA polymerase must stop to check its work every 1000-2000 nucleotides.
DNA polymerase requires a free 3' OH group to attach new nucleotides; primers are produced on the lagging strand every 1000-2000 nucleotides.
All of these are accurate statements.
None of these are accurate statements.
What is the major difference between T1 and T2 ?
A) T2 stops only counterclockwise-moving forks while T1 stops only clockwise-moving forks.
B) T1 work without need of ATP
C) T1 stops only counterclockwise-moving forks while T2 stops only clockwise-moving forks.
D) T2 work without need of ATP
B and C both are correct
What enzyme performs decatenation (unwind)?
Polymerase.
Topoisomerase.
Telomerase.
Decatenase.
Which of the following is a description of the proofreading function of DNA polymerase?
Endonuclease cleavage
Exonuclease cleavage.
Methylation.
An induced-fit phenomenon.
All of these.
Which of the following is a key difference between eukaryotic and prokaryotic DNA replication?
Eukaryotic origins of replication contain a high % of AT base pairs and require protein binding for correct function.
In eukaryotes, DNA replication proceeds bidirectionally from the origin of replication.
Eukaryotes contain several different DNA polymerases.
Telomerase is required to replicate the ends of eukaryotic chromosomes
None of these: They could all also describe prokaryotic DNA replication
What aspect of DNA polymerase function necessitates use of telomerase in eukaryotes?
3'-5' exonuclease function.
5'-3' processivity.
Induced fit impact on incorporation of only correct bases.
All of these.
None of these.
Telomerase activity in humans is generally restricted to the germ line, cancerous cells, and a few specific adult cell types. How would this be expected to impact humans?
Cancer cells can divide indefinitely.
Because there is a difference in number of divisions, sperm would be expected to have shorter telomeres than oocytes.
Rapidly dividing populations of cells have telomeres equal in size to slowly dividing populations of cells.
All of these.
None of these.
Base pairing rules are critical for the ability of each DNA strand to act as a template.
True
False
DNA replication requires an origin, where the two strands can be separated.
True
False
Mutations:
Are permanent changes in the DNA sequence or structure.
Produce allelic variation.
Are more likely to be harmful than beneficial
All of the above.
None of the above.
Mutations that cause loss of a chromosome would be termed:
Structural mutations
Chromosome mutations
Genome mutations
Single-gene mutations
None of these
A frameshift mutation could be caused by
A transition
A transversion
A deletion of 3 bp
All of these
None of these
من أٝضل دكتور على وجه الكرة الأرضية ؟؟
ٝوٝو
عامر امريش ههههه
مأمون
جلجل
هوه انتا لسا بتٝكر أكيد احمد سلمان
Because they only affect a single amino acid, missense mutations do not have a significant effect on protein function.
True
False
A wild type allele:
Is the allele that is the most common in the population.
Is the allele with the highest level of functional protein
Is the most favorable allele in the population
All of the above.
None of the above
The mutation which causes sickle cell anemia in humans:
Is a base substitution
Is a deleterious mutation
Is a missense mutation
All of the above
None of the above
Provided the number of base pairs is a multiple of three, insertion of additional DNA in the coding region of a protein is unlikely to have a dramatic effect on protein function
True
False
Which of the following would be an example of a germline mutation?
Exposure to excessive UV radiation causes changes in the DNA of a skin cell, leading to basal cell carcinoma (skin cancer).
In a very early human embryo, a mistake in mitosis causes loss of a Y chromosome in one daughter cell. The resulting child is a fertile male who is chromosomally partially male (XY) and partially female with Turner's syndrome (XO).
A man with normal chromosomes has a hip X-ray without a protective shield. Ten months later, his wife gives birth to a child with a chromosomal deletion.
An embryo missing one copy of the third chromosome is miscarried very early in pregnancy.
Mitochondrial DNA polymerase does not have an error checking mechanism such as that of nuclear DNA polymerase. This would be expected to lead to a higher rate of which type of mutation in mitochondrial DNA?
Spontaneous mutations
Induced mutations
Deletions
All of these
None of these
مين أحسن طالب ٝي الدٝعة هههههه ؟
محمد اللصاصمه
MOHAMMAD ALASASSMEH
Mohammad allasassmeh
جميع الخيارات صحيح
In a haploid organism, lethal alleles would be expected to:
Have a high mutation frequency
Have a high mutation rate
Be caused only by induced mutations
All of the above
None of the above
In which situation would you expect the mutation frequency to increase over time?
The deleterious effect of the mutation is balanced with the mutation rate
A lethal allele is created at a high mutation rate
A neutral allele is created at low mutation rate
All of the above
None of the above
Examples of environmental mutagens include:
Alkylating agents, which chemically modify bases
Nucleotide base analogues
Ionizing radiation
All of these
None of these
DNA repair systems typically work in three major steps: detection of the error, removal of the abnormality, and replacement of the removed DNA.
True
False
Which of the following forms of DNA repair does NOT require DNA polymerase?
Direct DNA repair.
Base excision repair
Nucleotide excision repair
Mismatch repair
Recombinational repair
Why is alkyltransferase only able to be used once?
The protein is hydrolyzed in the process of repairing the DNa.
The protein is chemically changed by the addition of a methyl group
The protein becomes attached to the DNA strand
All of these.
None of these
How does recombinational repair differ from nucleotide excision repair (NER)?
Unlike NER, recombinational repair is unable to repair damage caused by thymine dimers.
NER replaces the thymine dimmer while recombinational repair leaves it in place.
NER requires DNA polymerase and ligase function, while recombinational repair does not.
NER involves nick translation, which recombinational repair does not.
Mutational hot spots are sites in the DNA where a mutation is most likely to cause a change in protein structure.
True
False
Individuals with Cockayne syndrome are more likely to:
Have an increased rate of somatic mutation.
Have an increased rate of germ line mutation
Have a decreased rate of spontaneous mutation
Have a decreased rate of induced mutation
A new chemical pesticide developed for agricultural use was subjected to the Ames test. The rate of mutation seen in samples treated with the pesticide and liver extract was approximately half that of the samples treated with the liver extract alone; in samples treated with only pesticide, the mutation rate was about the same as that of untreated samples. Which of the following statements could you make about this pesticide?
The pesticide is modified by liver enzymes.
The pesticide is unlikely to be a mutagen
The pesticide may be protective against spontaneous mutation
All of the above
None of the above
Increasing environmental levels of mutagen is likely to lead to increasing frequency of deleterious alleles.
True
False
If there is a malfunction in the θ subunit in polymerase III, what is the consequence of this defect ?
A α subunit defect that causes errors in the DNA replication process
A ε subunit defect that causes errors in the DNA replication process
A beta subunit defect that causes errors in the DNA replication process
All of above
أيش طابخين اليوم ؟؟
منسٝ
منسٝ
منسٝ
جميع الخيارات صحيح
In the stage of division, a genetic transit occurs, and during this process a mutation occurs, what kind of mutation?
Deletion
Translocation
Inversion
Insertion
If you know that the animal has a shelf life of 15 years, and a 10-year sample is taken and clones occur, when will the risk of mutation increase?
5 years
8 years
3 years
one year
أرجوك ركز كويس
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