Non-Coding DNA & Regulatory Genes (AQA A Level Biology): Revision Note

Non-coding DNA & regulatory genes

• It can be highly difficult to translate the genome of complex organisms into their proteome

• The proteome is not the same in all cells, and it changes over time based on conditions and signals

Non-coding DNA

• Proteins are made from the coding regions of the genome, via transcription and translation.

• Determining the proteome of humans is difficult as large amounts of non-coding DNA are present in human genomes

  • The full genome includes introns and repetitive sequences

  • It can be very hard to identify these sections of DNA from the coding DNA

  • Simply knowing the sequence doesn't tell you which regions are coding or expressed

Regulatory genes

• Regulatory genes control the expression of other genes

• These genes do not code for proteins directly, but they influence which genes are transcribed and translated

• The presence of regulatory genes and the process of alternative splicing in human genomes also affect gene expression and the synthesis of proteins

• The proteome is larger than the genome due to:

  • alternative splicing

  • post-translational modification of proteins

    • The modification of the RNA molecule after transcription but before translation occurs, which often takes place in the Golgi apparatus