Genes & Proteins (Cambridge International IGCSE Biology)

DNA base sequence to amino acid sequence: Extended

Spec point — 17.1.3 · State that the sequence of bases in a gene determines the sequence of amino acids used to make a specific protein (knowledge of the details of nucleotide structure is not required) Explain that different sequences of amino acids give different shapes to protein molecules Explain that DNA controls cell function by controlling the production of proteins, including enzymes, membrane carriers and receptors for neurotransmitters

DNA base sequence to amino acid sequence: Extended

The DNA base sequence determines the amino acid sequence in protein

• The DNA code (a series of bases) is converted into proteins (a series of amino acids)

• The process of protein synthesis has two stages:

  • transcription - rewriting the base code of DNA into bases of RNA
  • translation - using RNA base sequence to build amino acids into sequence in a protein

• Therefore, the sequence of bases in a gene determines the sequence of amino acids that make a specific protein

• Different sequences of amino acids give different shapes and functions to protein molecules

Exam Hint It is easy to confuse sequences of bases (in DNA/RNA) with sequences of amino acids (in proteins).

Make sure you're clear which large molecule you're referring to and therefore, which monomers make up the larger molecule.