Non-coding DNA

• Most DNA in eukaryotic cells does what?

  DOES NOT CODE FOR POLYPEPTIDES
• What do some genes code for?

  • polypeptides
  • OR
  • Functional RNA
• In eukaryotic DNA, what do genes that DO code for polypeptides contain?


  Sections that do not code for amino acids (called introns)

  • There can be several introns within a gene
• What are all bits of a gene that do code for amino acids called?

  Exons
• When are introns removed?

  During protein synthesis - so they do not affect the amino acid order
• Does prokaryotic DNA have introns?

  NO- PROKARYOTIC DNA DOES NOT HAVE INTRONS
• What is the purpose of introns?

  is not known for sure
• What does eukaryotic DNA also contain?

  regions of multiple repeats outside of genes

  • These are DNA sequences that repeat over and over (eg CCTTCCTTCCTT)
  • These areas do not code for amino acids either, so they are called NON-CODING REPEATS