Question

Several antibiotics exert their action by targeting the unique protein synthesis processes in bacteria. They exploit the differences between prokaryotic and eukaryotic translation mechanisms to selectively inhibit protein synthesis in bacteria without affecting the eukaryotic host.Ribosomes are a specific target of some antibiotics since there is a significant difference in size and structure between eukaryotic and prokaryotic ribosomes; eukaryotic ribosomes consist of a 60S subunit and a 40S subunit, whereas prokaryotic ribosomes are 70S ribosomes consisting of a 50S large subunit and a 30S small subunit.Tetracycline is a common antibiotic that works at the level of protein synthesis in bacteria. Which of the following provides the BEST explanation for the effectiveness of Tetracycline as an antibiotic in eukaryotic cells?

Answer 1

The effectiveness of Tetracycline as an antibiotic in eukaryotic cells primarily stems from its selective targeting of prokaryotic ribosomes, which differ significantly from eukaryotic ribosomes. Tetracycline binds specifically to the 30S subunit of bacterial ribosomes, inhibiting the binding of aminoacyl-tRNA to the ribosomal mRNA. Since eukaryotic ribosomes have a different structure (the 40S and 60S subunits), Tetracycline does not effectively bind to them and thus does not interfere with the eukaryotic protein synthesis process.

In summary, Tetracycline is effective as an antibiotic because it specifically targets bacterial ribosomes (70S) without affecting eukaryotic ribosomes (80S), allowing it to inhibit protein synthesis in bacteria while leaving eukaryotic cells unharmed.