Question
Which of the following is used to cut DNA at specific base pair sequences?
(A) DNA ligase
(B) gel electrophoresis
(C) polymerase chain reaction
(D) restriction enzymes
▶️Answer/Explanation
Ans:
(D) Restriction enzymes (also known as restriction endonucleases) cut
DNA at specific base pair sequences. DNA ligase connects pieces of
DNA, so choice (A) is incorrect. Choice (B) is incorrect because gel
electrophoresis is used to separate DNA fragments according to their
size. Polymerase chain reaction (PCR) is used to amplify specific
sequences of DNA, so choice (C) is incorrect.
Question
A forensic scientist cuts DNA from a crime scene and DNA from a suspect with the same enzyme. Which tool should the scientist use to
separate the DNA fragments according to their size?
(A) bacterial transformation
(B) CRISPR-Cas9
(C) gel electrophoresis
(D) polymerase chain reaction
▶️Answer/Explanation
Ans:
(C) Gel electrophoresis separates fragments of DNA according to their
size. Bacterial transformation involves the uptake and expression of
foreign DNA by bacteria, so choice (A) is incorrect. CRISPR-Cas9 is
used for gene editing, so choice (B) is incorrect. PCR amplifies specific
sequences of DNA, so choice (D) is also incorrect.
Question
A forensic scientist cuts DNA from a crime scene and DNA from a suspect with the same enzyme. Which tool should the scientist use to
separate the DNA fragments according to their size?
(A) bacterial transformation
(B) CRISPR-Cas9
(C) gel electrophoresis
(D) polymerase chain reaction
▶️Answer/Explanation
Ans:
(C) Gel electrophoresis separates fragments of DNA according to their
size. Bacterial transformation involves the uptake and expression of
foreign DNA by bacteria, so choice (A) is incorrect. CRISPR-Cas9 is
used for gene editing, so choice (B) is incorrect. PCR amplifies specific
sequences of DNA, so choice (D) is also incorrect.
Question
A scientist at a pharmaceutical company wants to create bacteria that will synthesize human growth hormone.
What should the scientist use to add the DNA code for human growth hormone to a plasmid?
(A) bacterial transformation
(B) DNA ligase
(C) gel electrophoresis
(D) polymerase chain reaction
▶️Answer/Explanation
Ans:
(B) DNA ligase attaches DNA fragments together, joining them with
phosphodiester bonds. Choice (A) is incorrect because bacterial
transformation is used to insert naked, foreign DNA into a cell. Gel
electrophoresis separates DNA fragments by size, so choice (C) is
incorrect. Polymerase chain reaction is used to amplify the number of
copies of a specific sequence of DNA, so choice (D) is incorrect.
Question
A scientist at a pharmaceutical company wants to create bacteria that will synthesize human growth hormone.
The scientist has successfully created a plasmid that contains the DNA code for the human growth hormone gene.
Which technique should the scientist use to insert the plasmid into a cell?
(A) bacterial transformation
(B) CRISPR-Cas9
(C) gel electrophoresis
(D) polymerase chain reaction
▶️Answer/Explanation
Ans:
(A) Bacterial transformation inserts naked, foreign DNA into a
bacterial cell. CRISPR-Cas9 is used for gene editing, not inserting
plasmids into a cell, so choice (B) is incorrect. Choice (C) is incorrect
because gel electrophoresis is used to separate DNA fragments
according to their size. Polymerase chain reaction is used to amplify
the number of copies of a specific DNA sequence, so choice (D) is
incorrect.
Question
A scientist at a pharmaceutical company wants to create bacteria that will synthesize human growth hormone.
The scientist has successfully created a plasmid that contains the DNA code for the human growth hormone gene.
Which technique should the scientist use to insert the plasmid into a cell?
(A) bacterial transformation
(B) CRISPR-Cas9
(C) gel electrophoresis
(D) polymerase chain reaction
▶️Answer/Explanation
Ans:
(A) Bacterial transformation inserts naked, foreign DNA into a
bacterial cell. CRISPR-Cas9 is used for gene editing, not inserting
plasmids into a cell, so choice (B) is incorrect. Choice (C) is incorrect
because gel electrophoresis is used to separate DNA fragments
according to their size. Polymerase chain reaction is used to amplify
the number of copies of a specific DNA sequence, so choice (D) is
incorrect.
Question
Huntington’s disease is caused by a short tandem CAG repeat in the HTT gene. Individuals with fewer than 35 CAG repeats in the HTT gene do not develop Huntington’s disease. Individuals with 40 or more CAG repeats will develop Huntington’s disease.
Which of the following tools would be most useful in amplifying the number of copies of the HTT gene so that more DNA would be available for analysis?
(A) CRISPR-Cas9
(B) gel electrophoresis
(C) polymerase chain reaction
(D) restriction enzymes
▶️Answer/Explanation
Ans:
(C) Polymerase chain reaction makes multiple copies of a specific
DNA sequence and would be the best choice for amplifying the
number of copies of the HTT gene. Choice (A) is incorrect because
CRISPR-Cas9 is used for gene editing. Gel electrophoresis separates
fragments of DNA by size, so choice (B) is incorrect. Restriction
enzymes cut DNA at specific sequences, so choice (D) is incorrect.