3.3.2 Translation

Structure (collagen, spider silk)

Hormones (insulin, glucagon)

Immunity (antibodies)

Transport (protein channels)

Sensations (rhodopsin)

Movement (actin, myosin)

Enzymes (rubisco, amylase)

 

Genetic code to protein

  • Sequence of bases which provide instructions for making specific polypeptides

 

 

Translation

  • Takes place in the ribosomes

  • Involves taking genetic code from the mRNA and synthesising a polypeptide

    • A polypeptide is a sequence of amino acids covalently bonded together

    • The order of amino acids is based on the information stored in the genetic code of the mRNA

    • Occurs at the ribosomes

    • Involves transfer RNA or tRNA

tRNA

  • Each tRNA is specific for one amino acid

  • Each tRNA molecule of three bases called an anticodon and carries an amino acid corresponding to this anticodon

  • Anticodons are complementary to codons on the mRNA molecule

 

 

  1. Transcribed mRNA moves out of the nucleus via nuclear pores and combines with the ribosome

  2. tRNA molecules attach to the ribosome, and their anticodons pair up with the appropriate codons on the mRNA by complementary base pairing

  3. The amino acid transported by the tRNA link together (peptide bonds), and the tRNA molecules then return to the cytoplasm to attach to another free (but specific) amino acid

  4. Ribosome moves along mRNA, and amino acids continue to join together (peptide bonds form between them) until all the codons has been translated and the polypeptide is complete