Biology – Cells as the basic units of living organisms | e-Consult

70S ribosomes are crucial for protein synthesis in prokaryotic cells. Their name refers to the sedimentation rate at a given centrifugal force, indicating their size and composition. The 70S ribosome is composed of a 30S small subunit and a 50S large subunit. The structure of the 70S ribosome is directly related to its function. The 30S subunit binds to mRNA, ensuring accurate reading of the genetic code. The 50S subunit contains the peptidyl transferase center, the catalytic site where peptide bonds are formed between amino acids. This structure is distinct from the 80S ribosomes found in eukaryotic cells. Eukaryotic 80S ribosomes are larger and have a different subunit composition (60S large subunit and 40S small subunit). The differences in ribosomal structure are important because many antibiotics specifically target the 70S ribosomes in bacteria, inhibiting bacterial protein synthesis without significantly affecting eukaryotic cells. This selective toxicity is a key principle in antibiotic development.