CIE IGCSE Biology

Revision Notes

17.1.4 Protein Synthesis

Test Yourself

Transcription & Translation: Extended

Protein synthesis, IGCSE & GCSE Biology revision notesProtein synthesis

  

  • Proteins are made by ribosomes with the sequence of amino acids controlled by the sequence of bases contained within DNA
  • DNA cannot travel out of the nucleus to the ribosomes (it is far too big to pass through a nuclear pore) so the base code of each gene is transcribed onto an RNA molecule called messenger RNA (mRNA).
  • mRNA then moves out of the nucleus and attaches to a ribosome
  • The ribosome ‘reads’ the code on the mRNA in groups of three
  • Each triplet of bases codes for a specific amino acid
  • In this way the ribosome translates the sequence of bases into a sequence of amino acids that make up a protein
  • Once the amino acid chain has been assembled, it is released from the ribosome so it can fold and form the final structure of the protein

 

How ribosomes build proteins, IGCSE & GCSE Biology revision notes

 The triplet code of DNA (carried by mRNA) is read by the ribosome and amino acids are attached together in a specific sequence to form the protein

 

  • In this way, DNA controls cell function by controlling the production of proteins
  • The proteins may be enzymes, antibodies, or receptors for neurotransmitters
  • Although all body cells in an organism contain the same genes, many genes in a particular cell are not expressed because the cell only makes the specific proteins it needs

You've read 0 of your 0 free revision notes

Get unlimited access

to absolutely everything:

  • Downloadable PDFs
  • Unlimited Revision Notes
  • Topic Questions
  • Past Papers
  • Model Answers
  • Videos (Maths and Science)

Join the 80,663 Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Lára

Author: Lára

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.