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How do ribosomes make proteins?
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Ribosomes synthesize proteins through a process called translation, where the genetic information encoded in messenger RNA (mRNA) is converted into a specific sequence of amino acids.12
The process occurs in several key steps:
- Initiation: The mRNA binds to the smaller subunit of the ribosome. A specific transfer RNA (tRNA) carrying an amino acid pairs with the start codon on the mRNA, and the larger ribosomal subunit then joins the complex.3
- Elongation: The ribosome reads the mRNA in "words" of three nucleotides called codons. For each codon, a matching tRNA brings the corresponding amino acid to the ribosome. The ribosomal RNA (rRNA) within the ribosome catalyzes the formation of peptide bonds between these amino acids, linking them into a growing chain.1342
- Translocation: The ribosome moves along the mRNA one codon at a time, shifting the tRNAs between sites within the ribosome to continue adding amino acids.3
- Termination: When the ribosome encounters a stop codon, synthesis ends. The completed protein is released, and the ribosomal subunits dissociate from the mRNA.13