Antimicrobial Agents — MCQs

Q: All of the following bind to the 50S ribosomal unit except:

Tetracycline. ***Tetracycline*** - **Tetracyclines** bind to the **30S ribosomal subunit**, specifically inhibiting protein synthesis by blocking the binding of aminoacyl-tRNA to the A-site. - This mechanism is distinct from the other listed antibiotics which target the 50S subunit. *Macrolide* - **Macrolide antibiotics** bind to the **50S ribosomal subunit** to inhibit bacterial protein synthesis by blocking translocation and peptidyl transferase activity. - This binding prevents the ribosome from moving along the mRNA, effectively halting protein elongation. *Lincosamide* - **Lincosamides**, such as clindamycin, also bind to the **50S ribosomal subunit** at a site overlapping with macrolides and chloramphenicol. - They inhibit protein synthesis by hindering peptidyl transferase and stalling chain elongation. *Chloramphenicol* - **Chloramphenicol** binds to the **50S ribosomal subunit** and inhibits protein synthesis by blocking the peptidyl transferase activity. - This prevents the formation of peptide bonds between amino acids, thereby stopping protein chain elongation.

Practice by Chapter

Beta-Lactam Antibiotics

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Aminoglycosides

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Macrolides and Ketolides

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Tetracyclines

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Quinolones

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Sulfonamides and Trimethoprim

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Antimycobacterial Drugs

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Antifungal Agents

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Antiviral Drugs

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Antiparasitic Agents

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Principles of Antimicrobial Selection

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Antimicrobial Resistance

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