Question 1

Which of the following best describes the process of DNA denaturation and renaturation as used in genetic engineering techniques?

Accepted Answer

DNA is heated to 90°C–95°C to break hydrogen bonds and separate strands; slow cooling allows complementary nucleotides to rejoin and form double-stranded DNA.

Question 2

Restriction endonucleases are essential tools in genetic engineering. What is their primary function?

Accepted Answer

They recognize specific DNA sequences and break phosphodiester bonds between adjacent nucleotides.

Question 3

A scientist wants to join two DNA fragments from different organisms. Which property of restriction enzymes makes this possible?

Accepted Answer

They create sticky ends with complementary overhangs, allowing fragments from different sources to be joined if cut with the same enzyme.

Question 4

Which enzyme is necessary to rejoin phosphate-sugar bonds at sticky ends after DNA has been cut by restriction endonucleases?

Accepted Answer

DNA ligase

Question 5

In gel electrophoresis, DNA fragments are separated based on which property?

Accepted Answer

Size

Question 6

A researcher uses reverse transcriptase to synthesize DNA from mRNA. What is the main advantage of this approach in genetic engineering?

Accepted Answer

It allows synthesis of eukaryotic genes free of introns for expression in prokaryotic hosts.

Question 7

Which of the following is a key feature of a cloning vector used in recombinant DNA technology?

Accepted Answer

It must contain an origin of replication and a selectable marker such as a drug resistance gene.

Question 8

What is the main goal of recombinant DNA technology?

Accepted Answer

To clone a desired donor gene by inserting it into a vector and expressing it in a host organism.

Question 9

Which of the following is NOT a desirable feature in a microbial cloning host?

Accepted Answer

Pathogenic and difficult to culture.

Question 10

A patient with hemophilia requires replacement of a blood-clotting factor. Which product of recombinant DNA technology is used for this purpose?

Accepted Answer

Factor VIII

Question 11

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

Accepted Answer

A method to amplify DNA by cycling through denaturation, priming, and extension, doubling the number of copies each cycle.

Question 12

Which of the following is a real-world application of genetically modified organisms (GMOs) in agriculture?

Accepted Answer

Transgenic plants expressing insecticide genes to resist pest damage.

Question 13

A scientist wants to identify the presence and location of a specific DNA sequence in intact cells. Which technique should be used?

Accepted Answer

Fluorescent in situ hybridization (FISH)

Question 14

Which of the following is a major advantage of using Agrobacterium tumefaciens in plant genetic engineering?

Accepted Answer

It naturally transfers a large plasmid (Ti) into plant cells, allowing stable integration of foreign genes.

Question 15

Which of the following is a common use of DNA profiling in forensic science?

Accepted Answer

Identifying missing persons by comparing STR patterns from biological samples.

Question 16

A researcher is studying single nucleotide polymorphisms (SNPs) in a population. Why are SNPs valuable in biomedical research?

Accepted Answer

They are highly specific genetic variations that can affect disease onset and drug response.

Question 17

Which equation best represents the exponential amplification of DNA during PCR, where $$n is $$the number of cycles?

Accepted Answer

$$N = 2^n$$

Question 18

A transgenic mouse model is created to study cystic fibrosis. Which genetic engineering method is most likely used to introduce the human gene mutation?

Accepted Answer

CRISPR-Cas9 gene editing

Question 19

Which of the following is a direct application of microarray analysis in medicine?

Accepted Answer

Tracking the expression of thousands of genes to identify disease profiles and guide treatment.

Question 20

A scientist is using the Sanger sequencing method. Which component is essential for terminating DNA strand synthesis at specific bases?

Accepted Answer

Fluorescently labeled dideoxynucleotides (ddNTPs)

Chapter 10: Genetic Engineering: A Revolution in Molecular Biology

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