Question 1

Which of the following best explains why antibiotics are generally ineffective against viral infections such as the common cold?

Accepted Answer

Viruses lack the cellular structures targeted by antibiotics, such as cell walls and ribosomes.

Question 2

A patient is prescribed an antibiotic that inhibits protein synthesis. Which cellular structure is most likely targeted by this drug?

Accepted Answer

Ribosome

Question 3

Which of the following is a primary reason why fungal infections are more difficult to treat than bacterial infections?

Accepted Answer

Fungal cells are more similar to human cells, making selective toxicity harder to achieve.

Question 4

Which of the following best describes horizontal gene transfer (HGT) in bacteria?

Accepted Answer

The movement of genetic material between bacteria by mechanisms such as conjugation, transformation, or transduction.

Question 5

A hospital outbreak of antibiotic-resistant bacteria is traced to poor hand hygiene among staff. Which factor contributing to resistance does this scenario best illustrate?

Accepted Answer

Poor infection control

Question 6

Which of the following is an example of intrinsic resistance?

Accepted Answer

Gram-negative bacteria are resistant to vancomycin because the drug cannot penetrate their outer membrane.

Question 7

Which of the following best explains why stopping an antibiotic course early can promote the development of resistance?

Accepted Answer

Partially resistant bacteria survive and multiply, passing on resistance traits.

Question 8

Which of the following mechanisms is NOT a way bacteria can acquire antibiotic resistance genes?

Accepted Answer

Binary fission

Question 9

Why are soil-dwelling bacteria such as Streptomyces prolific producers of antibiotics?

Accepted Answer

They compete with many other microbes for resources, so producing antibiotics gives them a survival advantage.

Question 10

Which of the following is a major medical significance of the genus Streptomyces?

Accepted Answer

It is the source of over two-thirds of clinically useful antibiotics.

Question 11

A farmer routinely adds antibiotics to livestock feed to promote growth. What is a likely consequence of this practice?

Accepted Answer

Development and spread of antibiotic-resistant bacteria that can transfer to humans.

Question 12

Which of the following best describes acquired resistance in bacteria?

Accepted Answer

Resistance that develops through genetic changes such as mutation or horizontal gene transfer.

Question 13

Which of the following is NOT a major mechanism by which antimicrobial drugs act?

Accepted Answer

Inhibition of viral envelope formation

Question 14

A patient is infected with a bacterium that has acquired a plasmid carrying a resistance gene via conjugation. Which process allowed this gene transfer?

Accepted Answer

Direct transfer of DNA through a pilus between two bacteria.

Question 15

Which of the following scenarios best illustrates transformation as a mechanism of horizontal gene transfer?

Accepted Answer

A bacterium incorporates free DNA fragments from its environment into its genome.

Question 16

Which of the following best explains why antibiotics are not effective against protozoan infections?

Accepted Answer

Protozoa are eukaryotic and share many cellular features with human cells, making selective targeting difficult.

Question 17

Which of the following is a real-world consequence of not finishing a prescribed antibiotic course?

Accepted Answer

Surviving bacteria with partial resistance can multiply and spread, leading to harder-to-treat infections.

Question 18

Which of the following is a correct pairing of a natural antibiotic producer and the antibiotic it produces?

Accepted Answer

Penicillium – penicillin

Question 19

A bacterium is found to be resistant to multiple antibiotics due to the presence of several resistance genes acquired from different sources. Which process most likely contributed to this multidrug resistance?

Accepted Answer

Horizontal gene transfer

Question 20

Which of the following best explains why the overuse of antibiotics in both humans and agriculture accelerates the spread of resistance?

Accepted Answer

It increases selective pressure, allowing resistant bacteria to survive and multiply.

Antimicrobial Drugs: Mechanisms, Resistance, and Production

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