Question 1

Which of the following best describes a 'random' mutation in genetics?

Accepted Answer

A mutation that happens without regard to its phenotypic effect.

Question 2

Which of the following is a transition mutation?

Accepted Answer

Adenine (A) to Guanine (G)

Question 3

Why are transition mutations more common than transversions?

Accepted Answer

Transitions change a pyrimidine into a pyrimidine or a purine into a purine, which is less disruptive to DNA structure.

Question 4

A chemical mutagen, ethyl methane sulfonate (EMS), is most likely to cause which type of mutation?

Accepted Answer

G/C to A/T transition

Question 5

If the spontaneous mutation rate for a gene is $$5 	imes 10$$^{-5}$$ per gamete, how many expected births with this mutation would occur in a population of 2 million births?

Accepted Answer

$$200$$

Question 6

Which of the following best explains the outcome of the Luria & Delbrück fluctuation test?

Accepted Answer

Mutations for resistance arise randomly before exposure to the phage.

Question 7

Which of the following is NOT a possible cause of mutation?

Accepted Answer

Accurate DNA repair

Question 8

A frameshift mutation is most likely to result from which of the following?

Accepted Answer

An insertion or deletion of one or two nucleotides in a coding region

Question 9

Mutations in which region of a gene are most likely to affect RNA splicing?

Accepted Answer

Intron

Question 10

Which of the following best describes the role of p53 in the cell?

Accepted Answer

It induces apoptosis in response to DNA damage.

Question 11

A woman with a BRCA1 mutation is at increased risk for which of the following?

Accepted Answer

Breast and ovarian cancer

Question 12

Which of the following is a real-life consequence of a mutation in a DNA repair gene?

Accepted Answer

Increased risk of cancer due to accumulation of mutations

Question 13

Which of the following best describes a synonymous mutation?

Accepted Answer

A mutation that does not change the amino acid sequence of a protein

Question 14

Which of the following events during meiosis leads to crossing over?

Accepted Answer

Opposite sense resolution of Holliday junctions

Question 15

Which of the following is most likely to result from a mutation in the promoter region of a gene?

Accepted Answer

Reduced or altered transcription of the gene

Question 16

Which of the following best explains why not all insertions or deletions (indels) cause frameshift mutations?

Accepted Answer

Indels that are multiples of three nucleotides do not disrupt the reading frame

Question 17

Which of the following is a likely outcome if a mutation creates a cryptic splice site in an intron?

Accepted Answer

The mRNA will include extra sequence, causing a frameshift and altered amino acids

Question 18

Which of the following best describes the molecular consequence of depurination?

Accepted Answer

It leads to G/C to A/T transitions during DNA replication

Question 19

A population of bacteria is exposed to a virus. According to the random mutation hypothesis, what would you expect to observe?

Accepted Answer

The number of resistant cells will fluctuate among populations due to random timing of mutation

Question 20

Which of the following is the best definition of a gene conversion event during homologous recombination?

Accepted Answer

A process where one allele is converted to another due to mismatch repair within a heteroduplex region

Chapter 11

Guida di studio - Domande di pratica

Study guide - Flashcard