Difficulty: Easy
Correct Answer: Protein synthesis
Explanation:
Introduction / Context:
Aminoglycosides are potent bactericidal agents used for serious Gram-negative infections and synergistically for some Gram-positive infections. Their mechanism explains their spectrum, post-antibiotic effect, and toxicity.
Given Data / Assumptions:
Concept / Approach:
Aminoglycosides bind irreversibly to the 30S ribosomal subunit, causing misreading of mRNA and blocking initiation complexes. This leads to production of nonfunctional proteins and ultimately bacterial death. Entry is oxygen-dependent, explaining poor activity against strict anaerobes.
Step-by-Step Solution:
Locate target: 30S ribosomal subunit in bacteria.
Define effect: misreading and inhibition of initiation → faulty proteins.
Conclude primary interference: protein synthesis.
Verification / Alternative check:
Mutations in 30S components or methylation of 16S rRNA confer aminoglycoside resistance, confirming the mechanistic target.
Why Other Options Are Wrong:
Common Pitfalls:
Assuming all bactericidal drugs disrupt membranes or DNA; many, like aminoglycosides, kill via aberrant protein synthesis.
Final Answer:
Protein synthesis
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