Biological translation uses a ribosome to read messenger RNA codons and assemble the corresponding amino acid chain. Transfer RNA adaptors match codons through base pairing and carry the amino acids; the genetic code supplies the correspondence. The chain grows from the N-terminus toward the C-terminus, by adding each new residue at the C-terminus. See Clark, Douglas and Choi, Biology 2e: ribosomes, transfer RNA and protein synthesis.
In the gene expression diagram, read in the chosen reading frame. Under the standard genetic code, AUG specifies methionine and GCU specifies alanine; UAA is a stop codon. The result before any subsequent processing is the two-residue chain N–methionine–alanine–C, followed by termination. The stop codon contributes zero amino acids. See Clark, Douglas and Choi, Biology 2e: the standard genetic code. This example assumes appropriate initiation at the displayed AUG in a suitable context in a eukaryote; the diagram displays the coding segment, not a complete independently translatable messenger RNA.
Initiation establishes the starting position and reading frame, using a ribosome, an initiating transfer RNA and additional factors. At a standard stop codon, a release factor promotes release of the chain rather than delivery of another amino acid by transfer RNA. See Clark, Douglas and Choi: initiation and termination of translation. A short two-residue example illustrates decoding, not the size or folding of a typical functional protein.
The useful connection is between two different alphabets: nucleotides specify the order of amino acids through the genetic code. Base pairing helps select transfer RNA, while the ribosome catalyzes joining the delivered amino acids. The messenger RNA remains a template rather than being consumed as the chain's building material. Separating template, adaptor and product makes clear why transcription and biological translation are distinct mechanisms.
In biology, translation is a crucial process in the expression of genes, where the genetic code carried by messenger RNA (mRNA) is translated into a polypeptide chain, forming proteins. This process occurs in the ribosomes, which can be found in the cytoplasm or on the endoplasmic reticulum in eukaryotic cells.
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