Question 1

Which of the following best describes a transition mutation in DNA?

Accepted Answer

A purine is replaced by another purine, or a pyrimidine is replaced by another pyrimidine

Question 2

A researcher is using PCR to amplify a gene. Which of the following is NOT required for a successful PCR reaction?

Accepted Answer

Restriction endonucleases

Question 3

Which of the following statements about frameshift mutations is correct?

Accepted Answer

They often result in premature stop codons due to a shift in the open reading frame

Question 4

During gel electrophoresis, which DNA fragment will migrate the fastest through an agarose gel?

Accepted Answer

A short, supercoiled DNA fragment

Question 5

Which of the following best explains why DNA with a higher GC content has a higher melting temperature ($T_m$)?

Accepted Answer

GC base pairs have three hydrogen bonds, increasing the stability of the double helix

Question 6

A scientist wants to insert a gene into a plasmid using restriction enzymes. Which feature of the plasmid is essential for this process?

Accepted Answer

Multiple cloning site (MCS)

Question 7

Which of the following is a real-world application of PCR in forensic science?

Accepted Answer

Amplifying DNA from a few cells found at a crime scene to identify a suspect

Question 8

Which of the following best describes the function of dideoxynucleotides (ddNTPs) in Sanger sequencing?

Accepted Answer

They prevent further elongation of the DNA strand by lacking a 3' OH group

Question 9

A mutation changes the codon GAG (which codes for Glu) to GTG (which codes for Val) in the beta hemoglobin gene. What type of mutation is this?

Accepted Answer

Missense mutation

Question 10

Which of the following is a key difference between a transition and a transversion mutation?

Accepted Answer

Transitions involve purine to purine or pyrimidine to pyrimidine changes, while transversions involve purine to pyrimidine or vice versa

Question 11

Which of the following is NOT a common element found in a cloning vector?

Accepted Answer

Promoter for eukaryotic gene expression

Question 12

A scientist uses FISH (fluorescent in situ hybridization) to detect a specific DNA sequence in a chromosome. What is the principle behind this technique?

Accepted Answer

Hybridization of a fluorescently labeled probe to complementary DNA sequence

Question 13

Which of the following best describes the process of DNA denaturation?

Accepted Answer

Separation of double-stranded DNA into single strands by breaking hydrogen bonds

Question 14

A researcher is running a plasmid DNA sample on an agarose gel. Which form of the plasmid will migrate the fastest?

Accepted Answer

Supercoiled

Question 15

Which of the following is a direct result of a frameshift mutation in a coding region?

Accepted Answer

The reading frame is shifted, potentially altering every amino acid downstream

Question 16

Which of the following is a function of restriction endonucleases in molecular cloning?

Accepted Answer

Cutting DNA at specific recognition sequences to generate defined fragments

Question 17

Which of the following best explains why only one of the six possible reading frames in double-stranded DNA is usually translated?

Accepted Answer

The other reading frames are closed by frequent termination (stop) codons

Question 18

Which of the following is a real-world example of using recombinant DNA technology?

Accepted Answer

Producing human insulin in E. coli for diabetes treatment

Question 19

Which of the following is true about the directionality of DNA synthesis by DNA polymerase?

Accepted Answer

DNA polymerase synthesizes DNA in the 5' to 3' direction

Question 20

A scientist is designing a PCR experiment and wants to increase the melting temperature ($T_m$) of the primers. Which modification would be most effective?

Accepted Answer

Increase the number of GC base pairs in the primer

Methods in Molecular Biology: Mutation, DNA Structure, and Molecular Genetic Tools

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