How is a polypeptide made?

• polypeptide formation Step 1

  In the nucleus, the message in the gene is copied into an mRNA

  
• polypeptide formation Step 2

  The mRNA travels to the cytoplasm and attaches to a ribosome.

  
• polypeptide formation Step 3

  As the ribosome moves along the mRNA, it synthesises a polypeptide

  
• polypeptide formation Step 4

  When the ribosome leaves the mRNA, the polypeptide is released

  
• Determining sequence of amino acids in polypeptides


  • The sequence of the bases in a gene determines the sequence of the amino acids in a polypeptide.
  • Three bases on the DNA make up a codon.
  • One codon codes for one amino acid