Question
Which stage of DNA profiling involves the polymerase chain reaction (PCR)?
A. During extraction of the DNA sample
B. During replication of the DNA that has been cut with restriction enzymes
C. During electrophoresis to separate the DNA fragments on a gel
D. During incubation with labelled probes
▶️Answer/Explanation
Ans. B
Question
What is the role of DNA polymerase during DNA replication?
A. It adds nucleotides to the growing strand.
B. It adds nucleotides to the template strand.
C. It builds messenger RNA.
D. It carries out translation.
▶️Answer/Explanation
Ans. A
Question
Which sequence of bases and amino acids could be produced by transcription and translation of the DNA molecule shown?
Answer/Explanation
Markscheme
D
Question
What is replicated by a semi-conservative process?
A. Messenger RNA (mRNA) only
B. Messenger RNA (mRNA) and transfer RNA (tRNA) only
C. Messenger RNA (mRNA), transfer RNA (tRNA) and DNA only
D. DNA only
Answer/Explanation
Markscheme
D
Question
What enables bacteria to produce human growth hormone?
A. DNA replication is semi-conservative.
B. The polymerase chain reaction can be used.
C. They need the hormone for growth.
D. The genetic code is universal.
Answer/Explanation
Markscheme
D
Question
What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?
A. It can work at a wide range of pH.
B. It works at higher temperatures than most enzymes.
C. It can separate two strands of DNA.
D. It allows DNA to be replicated without the use of primers.
▶️Answer/Explanation
B
Question
Which are two proteins that assist in the unwinding and separation of DNA strands during replication?
A. Helicase and DNA polymerase III
B. DNA gyrase and DNA polymerase I
C. Helicase and DNA primase
D. Single-strand binding protein and DNA gyrase
▶️Answer/Explanation
D
Question
What is a function of the enzyme helicase?
A. It coils DNA up into a double helical shape.
B. It links DNA nucleotides in a new DNA strand.
C. It breaks hydrogen bonds between the DNA strands.
D. It forms temporary hydrogen bonds to produce messenger RNA.
▶️Answer/Explanation
C
Question
What is a function of DNA polymerase I?
A. Adds nucleotides in a 5’ to 3’ direction to elongate the chain
B. Uncoils the DNA double helix and splits it into two template strands
C. Removes RNA primer and replaces it with DNA
D. Produces sugar-phosphate bonds to link Okazaki fragments
▶️Answer/Explanation
C
Question
What is PCR used for?
A. Separate fragments of DNA by size
B. Amplify small amounts of DNA
C. Compare DNA samples
D. Genetically modify organisms’ DNA
▶️Answer/Explanation
B