This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti Microbial, Subject name: Pharmacology
Tetracyclines inhibit protein synthesis by acting on- 
Select and explain. 
A. 30-S ribosome, B. 50-S ribosome, C. Both 30-S & 50-S ribosome, D. 60-S ribosome
A: 30-S ribosome
Answer: A: 30-S ribosome 
Explanation: Ans. is 'a' i.e., 30-S ribosome Drugs binding to ribosome||||30-S ribosome50 -S ribosomeBoth 30-S & 50-So Tetracyclineo Streptomycino Chloramphenicolo Erythromycino Clindamycino Aminoglycosides (except streptomycin)Pleuromutilins (Retapamulin) new class of drug for topical treatment of impetigo due to MRSA and streptococcus. It acts by inhibiting protein synthesis after binding to 50 'S' ribosome.