AQA AS Biology

Revision Notes

4.1.7 Non-Coding DNA

Non-Coding DNA

  • The genome within eukaryotic cells contains many non-coding sections of DNA
    • Non-coding DNA does not code for any amino acids
  • Non-coding DNA can be found between genes, as non-coding multiple repeats
    • This means they contain the same base sequences repeated multiple times
  • Non-coding DNA can also be found within genes, as introns
    • The coding exons can be separated by one or more introns
  • During transcription, eukaryotic cells transcribe the whole gene (all introns and exons) to produce pre-mRNA molecules
  • Before the pre-mRNA exits the nucleus the non-coding sections (introns) are removed and the coding sections (exons) are joined together in a process called splicing

_Post-transcriptional modification of RNA, downloadable AS & A Level Biology revision notes

The RNA molecule produced from the transcription of a gene contains introns that must be removed before translation can occur.

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.
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