Puromycin terminates translation because it structurally resembles:

• A The Shine-Dalgarno sequence of bacterial mRNA
• B The 3' terminal adenosine of tRNA linked to an amino acid ✓
• C GTP bound to elongation factor Tu
• D The branch point adenosine of a lariat intermediate

Explanation

Puromycin is an analog of aminoacyl-adenosine, the 3' end of a charged tRNA. It enters the B site, accepts the growing peptide via peptidyl transferase, and because it lacks the rest of the tRNA and cannot translocate, the peptidyl-puromycin complex dissociates, releasing an incomplete chain. It acts on both prokaryotic and eukaryotic ribosomes. Chloramphenicol, by contrast, blocks peptidyl transferase without mimicking aminoacyl-tRNA.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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