Protein synthesis links DNA information to functional proteins through transcription, RNA processing, translation, genetic-code reading and post-translational modification in cells.
Coverage 2010–2025 · Updated 16 Jul 2026
• Transcription makes mRNA as a mobile copy of gene information
• RNA polymerase synthesizes RNA complementary to the DNA template strand
• Free RNA nucleotides align by complementary base pairing and hydrogen bonding
• DNA adenine pairs with RNA uracil, while cytosine pairs with guanine
• DNA template strands are transcribed without altering the base sequence
• Sugar-phosphate backbone and base pairing preserve genetic information
• Transcription is the first stage of gene expression
• Cells regulate which genes are transcribed according to tissue, stage, and signals
• Translation decodes mRNA at ribosomes to synthesize polypeptides
• mRNA codon order determines amino acid sequence
• mRNA provides codons; tRNA carries activated amino acids with anticodons
• Ribosomes hold mRNA and tRNAs so peptide bonds can form
• tRNA anticodons pair with complementary mRNA codons by hydrogen bonding
• Specific tRNA-amino acid attachment helps ensure correct amino acid addition
• The genetic code is triplet, degenerate, and almost universal
• Codons specify amino acids, a start signal, or stop signals
• Genetic code tables use mRNA codons, not DNA triplets
• Convert template DNA to mRNA first, then read codons 5' to 3'
• Ribosomes move along mRNA one codon at a time from start to stop
• Peptide bonds join amino acids; multiple ribosomes can form a polysome
• Mutations can change codons and therefore amino acid sequence
• Changed primary structure may alter folding and function, such as sickle-cell haemoglobin
