Definition
Large molecular machine (2.5–4.2 MDa) that reads messenger RNA (mRNA) and catalyzes the assembly of amino acids into peptide chains — the biological site of peptide synthesis (translation).

Detailed Explanation

Large molecular machine (2.5–4.2 MDa) that reads messenger RNA (mRNA) and catalyzes the assembly of amino acids into peptide chains — the biological site of peptide synthesis (translation). Ribosomes consist of a large and small subunit, each made of ribosomal RNA (rRNA) and proteins. The catalytic activity resides in the rRNA, making the ribosome a ribozyme.

During translation, transfer RNA (tRNA) molecules deliver amino acids to the ribosome's active site, where peptide bonds are formed at a rate of ~15–20 amino acids per second in bacteria. The ribosome translates mRNA codons in the N→C direction. Understanding ribosomal structure earned Venkatraman Ramakrishnan, Thomas Steitz, and Ada Yonath the Nobel Prize in Chemistry (2009).

Key Facts

  • Large molecular machine (2.5–4.2 MDa) that reads messenger RNA (mRNA) and catalyzes the assembly of amino acids into peptide chains — the biological site of peptide synthesis (translation).
  • Ribosomes consist of a large and small subunit, each made of ribosomal RNA (rRNA) and proteins.
  • The catalytic activity resides in the rRNA, making the ribosome a ribozyme.
  • During translation, transfer RNA (tRNA) molecules deliver amino acids to the ribosome's active site, where peptide bonds are formed at a rate of ~15–20 amino acids per second in bacteria.
  • The ribosome translates mRNA codons in the N→C direction.
  • Understanding ribosomal structure earned Venkatraman Ramakrishnan, Thomas Steitz, and Ada Yonath the Nobel Prize in Chemistry (2009).
Related Terms Peptide Bond Amino Acid N Terminus Condensation Reaction Protein

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