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 gel electrophoresis is correct?

Accepted Answer

Supercoiled DNA runs faster than linear DNA of the same length

Question 4

A frameshift mutation is most likely to occur when:

Accepted Answer

The number of nucleotides inserted or deleted is not a multiple of 3

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

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

Accepted Answer

Amplifying DNA from a single hair at a crime scene to identify a suspect

Question 7

A scientist uses EcoRI to cut both a plasmid and a gene of interest, then ligates them together. What is the main reason EcoRI is useful for this process?

Accepted Answer

EcoRI creates sticky ends that facilitate the insertion of the gene into the plasmid

Question 8

Which of the following mutations is most likely to result in a truncated, nonfunctional protein?

Accepted Answer

Nonsense mutation

Question 9

During Sanger sequencing, what is the role of dideoxynucleotides (ddNTPs)?

Accepted Answer

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

Question 10

Which of the following best describes the process of hybridization in molecular biology?

Accepted Answer

The joining of complementary nucleic acid strands to form a double-stranded molecule

Question 11

A mutation changes the codon GAG (Glu) to GTG (Val) in the beta hemoglobin gene, causing sickle cell disease. What type of mutation is this?

Accepted Answer

Missense mutation

Question 12

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

Accepted Answer

DNA polymerase gene

Question 13

A researcher wants to determine where and when a gene is expressed in a developing organism. Which tool would be most appropriate?

Accepted Answer

Reporter construct with GFP

Question 14

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 stop codons

Question 15

Which of the following is a real-world example of a chromosomal rearrangement mutation?

Accepted Answer

An inversion of a chromosome segment

Question 16

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 17

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

Accepted Answer

Supercoiled DNA

Question 18

Which of the following is a key reason why restriction endonucleases are useful in molecular cloning?

Accepted Answer

They recognize specific palindromic DNA sequences and cut at those sites

Question 19

Which of the following best describes the principle behind FISH (Fluorescent in situ Hybridization)?

Accepted Answer

It uses fluorescently labeled probes to detect and locate specific DNA or RNA sequences in cells or tissues

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

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