Question 1

Which of the following best describes the role of primers in the Polymerase Chain Reaction (PCR)?

Accepted Answer

Primers bind to the template DNA and define the region to be amplified by providing a free 3'-OH group for DNA polymerase.

Question 2

A researcher is designing a PCR primer. Which of the following properties should the primer have to ensure specificity and efficiency?

Accepted Answer

A length of 18-24 bases, 40-60% G/C content, and a Tm of 50-60°C.

Question 3

Which enzyme is responsible for forming phosphodiester bonds between DNA fragments during the creation of recombinant DNA molecules?

Accepted Answer

DNA ligase

Question 4

A scientist wants to clone a gene into a plasmid vector. Both the gene and the plasmid are digested with EcoRI. What is the main advantage of using the same restriction enzyme for both DNA samples?

Accepted Answer

It ensures that the gene and plasmid have compatible sticky ends for ligation.

Question 5

Which of the following is a key ethical concern associated with germline gene editing in humans?

Accepted Answer

The inability of future generations to consent to genetic changes.

Question 6

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

Accepted Answer

They terminate DNA synthesis by lacking a 3'-OH group.

Question 7

Which of the following best explains why restriction enzymes do not degrade bacterial genomic DNA?

Accepted Answer

Bacterial DNA is protected by methylation at restriction sites.

Question 8

A genomic library is constructed by fragmenting genomic DNA and ligating the fragments into vectors. Which vector would be most appropriate for cloning very large DNA fragments (over 100 kb)?

Accepted Answer

Bacterial Artificial Chromosome (BAC)

Question 9

Which of the following is a major difference between a genomic library and a cDNA library?

Accepted Answer

A genomic library contains all DNA sequences, including introns and regulatory regions, while a cDNA library contains only expressed genes (exons).

Question 10

In the Human Genome Project, what was the main advantage of the whole-genome shotgun sequencing approach compared to the hierarchical (clone-by-clone) approach?

Accepted Answer

It allowed for faster sequencing by randomly fragmenting and sequencing the entire genome at once.

Question 11

Which of the following best describes the process of RNA interference (RNAi)?

Accepted Answer

Double-stranded RNA is processed into siRNAs, which guide the RISC complex to degrade complementary mRNA.

Question 12

A researcher is using PCR to amplify a DNA fragment. If the annealing temperature is set too low, what is the most likely outcome?

Accepted Answer

Primers may bind non-specifically, resulting in amplification of unintended DNA fragments.

Question 13

Which of the following equations correctly represents the exponential amplification of DNA during PCR, where $$n is $$the number of cycles?

Accepted Answer

$$2^n$$

Question 14

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

Accepted Answer

Production of human insulin in bacteria for diabetes treatment.

Question 15

A scientist is using Sanger sequencing with fluorescently labeled ddNTPs. What is the main advantage of this method over radioactive labeling?

Accepted Answer

It allows all four chain-termination reactions to be performed in a single tube and detected by fluorescence.

Question 16

Which of the following best explains why vectors are essential in recombinant DNA technology?

Accepted Answer

Vectors carry foreign DNA into host cells, allowing for replication and expression of the inserted gene.

Question 17

A researcher is analyzing a DNA sequence using restriction fragment length polymorphism (RFLP). Which property of restriction enzymes is most critical for this technique?

Accepted Answer

Their ability to recognize and cut specific DNA sequences.

Question 18

Which of the following statements about the directionality of DNA synthesis is correct?

Accepted Answer

DNA synthesis proceeds in the 5' to 3' direction by addition of nucleotides to the 3'-OH group.

Question 19

Which of the following is a potential environmental risk associated with genetically modified organisms (GMOs)?

Accepted Answer

Escape of GMOs into the environment, potentially disrupting ecosystems.

Recombinant DNA Technology: Principles, Methods, and Applications

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