Q: Which equation best represents the flow of genetic information in retroviruses?

$$\text{RNA} \rightarrow \text{DNA} \rightarrow \text{Protein}$$

Question 1

Which of the following best describes a genetically-modified organism (GMO)?

Accepted Answer

An organism whose genome has been precisely modified by human intervention, including gene deletion, modification, replacement, or addition from the same or another species.

Question 2

Why is it necessary to use cDNA instead of genomic DNA when cloning the human insulin gene into bacteria?

Accepted Answer

Because cDNA lacks introns, which bacteria cannot process, allowing proper translation of the insulin protein.

Question 3

Which feature of plasmids makes them particularly useful for recombinant DNA technology?

Accepted Answer

They are small, circular, extrachromosomal DNA molecules that replicate independently and often carry selectable markers such as antibiotic resistance genes.

Question 4

A restriction enzyme recognizes the sequence $$5'\ GAATTC\ 3'$$ and cuts between G and A. What type of ends does this enzyme produce?

Accepted Answer

Sticky ends with a 5' overhang

Question 5

What is the primary reason for the rapid expansion of antibiotic resistance in bacteria?

Accepted Answer

Natural selection acting on bacterial populations exposed to antibiotics, allowing resistant mutants to survive and proliferate.

Question 6

In the process of gene cloning, why is an inducible promoter such as the lac promoter used?

Accepted Answer

To ensure the gene of interest is expressed only when desired, allowing controlled production of the protein.

Question 7

Which equation best represents the flow of genetic information in retroviruses?

Accepted Answer

$$	ext{RNA} ightarrow 	ext{DNA} ightarrow 	ext{Protein}$$

Question 8

A bacterial colony grows on an ampicillin plate after transformation with a plasmid. What does this indicate about the colony?

Accepted Answer

The colony contains a plasmid with an ampicillin resistance gene.

Question 9

Which of the following is a real-world application of genetically-modified bacteria?

Accepted Answer

Production of human insulin for diabetes treatment.

Question 10

What is the function of DNA ligase in recombinant DNA technology?

Accepted Answer

To join DNA fragments by repairing the sugar-phosphate backbone.

Question 11

If a plasmid with a gene insert is digested with AatII and produces bands of 3.2 kb and 2.3 kb, what does this indicate?

Accepted Answer

The insert is in the correct orientation.

Question 12

Which of the following best explains why bacteria can quickly acquire antibiotic resistance?

Accepted Answer

Bacteria can mutate their own genes and acquire resistance genes from other bacteria via plasmid transfer.

Question 13

What is the purpose of using X-gal in bacterial transformation experiments?

Accepted Answer

To distinguish between bacteria with functional lacZ gene (blue colonies) and those with disrupted lacZ gene (white colonies, containing recombinant DNA).

Question 14

Which of the following is NOT a reason for the expansion of antibiotic resistance according to the World Health Organization?

Accepted Answer

Exclusive use of antibiotics in plant breeding.

Question 15

Which step is necessary to ensure that a recombinant plasmid expresses a human protein in bacteria?

Accepted Answer

Insert the human gene downstream of a bacterial promoter in the plasmid.

Question 16

Which equation describes the relationship between the distance migrated by a DNA fragment in agarose gel electrophoresis and its size?

Accepted Answer

$$d \propto \frac{1}{\log_{10}(s)}$$

Question 17

Which of the following is a major health concern associated with multidrug-resistant bacteria?

Accepted Answer

Minor injuries can become fatal due to lack of effective antibiotics.

Question 18

What is the role of the Shine-Dalgarno sequence in bacterial expression vectors?

Accepted Answer

It facilitates efficient translation by aligning the ribosome with the start codon.

Question 19

Which of the following statements about restriction enzymes is correct?

Accepted Answer

They cut DNA at specific palindromic sequences, producing either blunt or sticky ends.

Biotechnology and Recombinant DNA Technology: Principles and Applications 21

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