Antibacterial Agents Quiz

Who is credited with the discovery of bacteria in the 1670s?

• Pasteur

• Chain

• van Leeuwenhoek

• Florey

Answer explanation

The discovery of bacteria in the 1670s is credited to van Leeuwenhoek, who made significant contributions to microbiology.

Which of the following is an example of an antimetabolite antibacterial agent?

• Vancomycin

• Cephalosporins

• Streptomycin

• Sulphonamides

Answer explanation

Sulphonamides is an example of an antimetabolite antibacterial agent. It inhibits the synthesis of folic acid, which is essential for bacterial growth. Other options are not antimetabolite antibacterial agents.

What is the main mechanism of action of penicillins and cephalosporins?

• Inhibition of bacterial cell wall synthesis

• Interactions with the plasma membrane

• Inhibition of cell metabolism

• Inhibition of DNA replication

Answer explanation

Penicillins and cephalosporins work by inhibiting bacterial cell wall synthesis, which is their main mechanism of action.

Which type of bacteria have an additional outer membrane not present in Gram-positive bacteria?

• Bacteria with a thick cell wall

• Bacteria with a thin cell wall

• Gram-positive bacteria

• Gram-negative bacteria

Answer explanation

Gram-negative bacteria have an additional outer membrane not present in Gram-positive bacteria.

Who is considered the father of chemotherapy for his work on selective toxicity against microorganisms?

• Lister

• Paul Ehrlich

• Florey

• Chain

Answer explanation

Paul Ehrlich is considered the father of chemotherapy for his groundbreaking work on selective toxicity against microorganisms.

What is the primary mode of action of sulphonamides?

• Interactions with the cell wall

• Disruption of protein synthesis

• Inhibition of nucleic acid transcription and replication

• Inhibition of cell metabolism

Answer explanation

Sulphonamides primarily inhibit cell metabolism, making it the correct choice.

What is the main reason why sulphonamides are not toxic to human cells?

• Human cells have a higher resistance to sulphonamides

• Human cells have a transport protein for folic acid

• Human cells synthesize tetrahydrofolate in a different manner

• Human cells lack the enzyme dihydropteroate synthetase

Answer explanation

Sulphonamides are not toxic to human cells because human cells synthesize tetrahydrofolate differently.

What is the primary target of trimethoprim?

• Plasma membrane

• Dihydropteroate synthetase

• Dihydrofolate reductase

• Cell wall synthesis

Answer explanation

Trimethoprim primarily targets dihydrofolate reductase, inhibiting its activity and disrupting folate metabolism. This impairs bacterial growth and survival.

What is the main reason for the success of sulphonamides in treating bacterial infections?

• Bacteria have a different mode of action for sulphonamides

• Bacteria have a transport protein for folic acid

• Bacteria have a higher resistance to sulphonamides

• Bacteria have a susceptible enzyme not present in mammalian cells

Answer explanation

Sulphonamides are successful in treating bacterial infections because bacteria have a susceptible enzyme not found in mammalian cells.

Which of the following is NOT an example of an antimetabolite in medical use?

• Polymyxins

• Tyrothricin

• Trimethoprim

• Sulphones

Answer explanation

Polymyxins is not an example of an antimetabolite in medical use.