Question 1

Which of the following best describes the function of restriction enzymes in recombinant DNA technology?

Accepted Answer

They cut DNA at specific recognition sequences, producing fragments with sticky or blunt ends.

Question 2

A researcher wants to clone a gene using a plasmid vector and blue-white screening. After transformation, which colonies should be selected for further analysis?

Accepted Answer

Ampicillin resistant, white colonies

Question 3

Which feature is NOT essential for a plasmid to function as a cloning vector?

Accepted Answer

The ability to carry DNA fragments up to 200 kb

Question 4

What is the main advantage of using sticky ends over blunt ends in DNA cloning?

Accepted Answer

Sticky ends allow for easier and more specific annealing of DNA fragments due to complementary overhangs.

Question 5

Which of the following statements about cDNA libraries is correct?

Accepted Answer

They are constructed by reverse transcribing mRNA into DNA.

Question 6

During PCR, what is the purpose of the denaturation step?

Accepted Answer

To separate double-stranded DNA into single strands

Question 7

A forensic scientist needs to amplify a small amount of DNA found at a crime scene. Which technique should they use?

Accepted Answer

Polymerase chain reaction (PCR)

Question 8

Which of the following is a limitation of PCR?

Accepted Answer

It requires prior knowledge of the target DNA sequence to design primers.

Question 9

In agarose gel electrophoresis, which DNA fragments migrate the farthest?

Accepted Answer

The smallest fragments

Question 10

Which of the following best describes the Southern blot technique?

Accepted Answer

It separates DNA fragments by size, transfers them to a membrane, and detects specific sequences with a labeled probe.

Question 11

A scientist uses CRISPR-Cas9 to introduce a double-stranded break in a gene. Which repair mechanism can result in a frameshift mutation?

Accepted Answer

Nonhomologous end-joining (NHEJ)

Question 12

Which of the following is a potential problem when using CRISPR-Cas9 for genome editing?

Accepted Answer

sgRNA may direct Cas9 to off-target sites with similar sequences.

Question 13

Which of the following is NOT a step in the Sanger sequencing method?

Accepted Answer

Amplification of DNA by PCR

Question 14

Which of the following statements about expression vectors is correct?

Accepted Answer

They are designed to ensure that the cloned gene is transcribed and translated in the host cell.

Question 15

A genomic library constructed from eukaryotic DNA will contain:

Accepted Answer

Both coding and noncoding sequences, including introns

Question 16

Which of the following is a real-world application of quantitative real-time PCR (qPCR)?

Accepted Answer

Quantifying the amount of a specific DNA or RNA sequence in a sample

Question 17

Which of the following is true about the use of probes in library screening?

Accepted Answer

A probe is a labeled DNA or RNA sequence complementary to the target gene.

Question 18

Which of the following best explains why cDNA libraries are useful for studying cancer genes?

Accepted Answer

They represent only the genes expressed at the time the library was made, allowing identification of genes involved in cancer formation.

Question 19

Which of the following is a key requirement for PCR amplification?

Accepted Answer

Primers complementary to the 5' and 3' ends of the target sequence

Question 20

In a transcriptome analysis, it was found that ~52% of all sea urchin genes were expressed during the first 48 hours of development. What does this mean?

Accepted Answer

RNA was produced from 52% of the genes

Recombinant DNA Technology: Tools, Methods, and Applications

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