BRAINCAKETranslation
Translation is the second stage of protein synthesis: the mRNA base sequence is used to make a polypeptide with a specific amino acid sequence. It happens at a ribosome.
1. The mRNA binds to the small subunit of a ribosome, at the start codon AUG.
2. A tRNA with the complementary anticodon (UAC) pairs with the start codon by hydrogen bonds, bringing methionine.
3. A second tRNA, carrying its specific amino acid, pairs with the next codon. The ribosome holds two tRNA molecules at a time.
4. A peptide bond forms between the two amino acids in a condensation reaction, catalysed by the ribosome.
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Key terms in this lesson
- codon
- A sequence of three bases on mRNA that codes for one amino acid or a stop signal during translation.
- trna
- Transfer RNA: a small, folded RNA molecule that carries a specific amino acid to the ribosome and pairs with mRNA via its anticodon.
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