Question 1

Which of the following best describes the main advantage of using site-directed mutagenesis over traditional mutagenic alteration in genetic engineering?

Accepted Answer

It enables targeted changes at specific nucleotide sequences, increasing precision.

Question 2

A researcher wants to express a human protein that requires complex glycosylation for its function. Which host organism should they choose and why?

Accepted Answer

Saccharomyces cerevisiae, because it can perform eukaryotic post-translational modifications.

Question 3

Which of the following is a key reason why restriction enzymes do not degrade the host bacterium's own DNA?

Accepted Answer

The host DNA is protected by methylation of cytosine or adenine residues.

Question 4

A scientist is using the polymerase chain reaction (PCR) to amplify a DNA segment. If the reaction runs for $$n$$ cycles, what is the theoretical number of DNA copies produced, assuming perfect efficiency?

Accepted Answer

$$2^n$$

Question 5

Why is complementary DNA (cDNA) used instead of genomic DNA when expressing eukaryotic genes in bacteria?

Accepted Answer

cDNA contains only exons, avoiding introns that bacteria cannot process.

Question 6

Which DNA insertion technique is most appropriate for introducing foreign DNA into animal oocytes or embryos?

Accepted Answer

Microinjection using a fine glass needle.

Question 7

A company wants to produce a vaccine subunit protein that requires secretion into the culture medium for easy purification. Which host organism is most suitable?

Accepted Answer

Saccharomyces cerevisiae, because it safely secretes products.

Question 8

Which of the following best explains the function of shuttle vectors in genetic engineering?

Accepted Answer

They can replicate in multiple host species, such as both bacteria and yeast.

Question 9

A plant biotechnologist wants to create a crop resistant to insect larvae. Which genetic modification strategy should they use?

Accepted Answer

Integrate the Bt toxin gene into the plant genome.

Question 10

Which of the following is a major limitation of using mammalian cells as hosts for recombinant protein production?

Accepted Answer

They are expensive to maintain and grow very slowly.

Question 11

A forensic scientist needs to identify a suspect using a small DNA sample from a crime scene. Which technique should be used to amplify the DNA for analysis?

Accepted Answer

Polymerase Chain Reaction (PCR)

Question 12

Which of the following best describes the purpose of a genomic library?

Accepted Answer

It stores the entire genomic DNA sequence of an organism in a population of clones.

Question 13

A scientist is using Southern blotting in their research. What is the main purpose of this technique?

Accepted Answer

To detect specific DNA fragments using labeled hybridization probes after electrophoresis.

Question 14

Which of the following is a real-world application of antisense DNA technology in agriculture?

Accepted Answer

Delaying fruit spoilage by suppressing post-harvest softening genes.

Question 15

A researcher is designing a synthetic gene using automated chemical DNA synthesis. Which step ensures the accuracy of the final gene before it is inserted into a host?

Accepted Answer

Verification by DNA sequencing.

Question 16

Which of the following best explains why Escherichia coli is not suitable for producing certain human therapeutic proteins?

Accepted Answer

It cannot perform complex post-translational modifications required for some proteins.

Question 17

Which of the following is a key feature of reverse-transcription PCR (RT-PCR) that distinguishes it from standard PCR?

Accepted Answer

It uses RNA templates to synthesize complementary DNA before amplification.

Question 18

A biotechnologist wants to introduce a gene into plant cells that have a rigid cell wall. Which DNA insertion method is most effective for this purpose?

Accepted Answer

Gene gun bombardment with DNA-coated microparticles.

Question 19

Which of the following is a direct benefit of using nanotechnology in medicine, as described in the study materials?

Accepted Answer

Targeted drug delivery using nanospheres inside the human body.

Question 20

A patient is diagnosed with a genetic disorder caused by a single point mutation. Which modern biotechnology tool is most suitable for correcting this mutation in vivo?

Accepted Answer

CRISPR-Cas9 gene editing system.

Biotechnology & DNA Technology: Principles, Tools, and Applications

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