Q: Which equation best represents the mutation rate ($$\mu) $$for a gene in a population?

$$\mu = \frac{\text{Number of mutations}}{\text{Number of gametes or generations}}$$

Question 1

Which type of mutation results in a premature stop codon, leading to early termination of translation?

Accepted Answer

Nonsense mutation

Question 2

A frameshift mutation is most likely to occur due to which of the following events?

Accepted Answer

Insertion or deletion of a nucleotide

Question 3

Which equation best represents the mutation rate ($$\mu) $$for a gene in a population?

Accepted Answer

$$\mu = \frac{	ext{Number of mutations}}{	ext{Number of gametes or generations}}$$

Question 4

Which of the following mutations is NOT heritable?

Accepted Answer

Somatic mutation

Question 5

A patient with Huntington disease has more than 40 repeats of the (CAG) sequence in the coding region of the Huntingtin gene. What type of mutation is this?

Accepted Answer

Trinucleotide repeat expansion

Question 6

Which of the following best describes a dominant negative mutation?

Accepted Answer

A mutation where one allele encodes an inactive gene product that interferes with the function of the normal allele

Question 7

Which chemical agent is known to wedge between DNA base pairs, causing distortions and unwinding of the DNA helix?

Accepted Answer

Intercalating agent

Question 8

A mutation in the TATA sequence at -30 upstream from the transcription start site of the HBB gene results in decreased gene transcription and severe disease. What type of mutation is this?

Accepted Answer

Mutation in the 5' upstream region

Question 9

Which of the following is a mutagenic effect of 5-bromouracil (5-BU)?

Accepted Answer

It behaves as a thymine analog and pairs with adenine in its keto form, but pairs with guanine in its enol form

Question 10

Which of the following is a consequence of ionizing radiation on DNA?

Accepted Answer

Creation of free radicals that break phosphodiester bonds and cause deletions, translocations, and fragmentation

Question 11

A mutation that changes a glycine to arginine at position 380 of the FGFR3 gene is classified as which type?

Accepted Answer

Missense mutation

Question 12

Which of the following best describes replication slippage?

Accepted Answer

DNA polymerase slips or stutters, causing loops in the template strand and resulting in small insertions or deletions

Question 13

Which of the following is a characteristic of spontaneous mutations?

Accepted Answer

They occur naturally, often during DNA replication

Question 14

Which of the following is a real-world example of a disease caused by a single-gene deletion mutation?

Accepted Answer

Cystic fibrosis

Question 15

Which of the following best describes the effect of UV radiation on DNA?

Accepted Answer

It causes the formation of pyrimidine dimers, distorting DNA conformation

Question 16

A mutation that results in a new triplet code for the same amino acid is called:

Accepted Answer

Silent mutation

Question 17

Which of the following is a polygenic disease?

Accepted Answer

Most human genetic diseases

Question 18

Which of the following is a plausible outcome of oxidative damage to DNA?

Accepted Answer

Modification of bases, loss of bases, and single-stranded breaks

Question 19

Which of the following best describes a suppressor mutation?

Accepted Answer

A second mutation that reverts or relieves the effects of a previous mutation

Question 20

Which of the following is a plausible effect of an alkylating agent on DNA?

Accepted Answer

It donates an alkyl group to amino or keto groups in nucleotides, altering base-pairing affinity and causing transition mutations

Ch 14 P1 Gene Mutation, DNA Repair, and Transposition: Mechanisms and Consequences

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