AQA A Level Biology

Revision Notes

4.2.1 The Genome

The Genome

  • A gene is a length of DNA that codes for a polypeptide/protein
  • A genome is the complete set of genes present in a cell
  • The full genome is present within every cell of an organism, but not every gene is expressed in every cell. Which genes are expressed depends on the cell type
  • The proteome is the full range of proteins that a cell is able to produce
  • The proteome is usually larger than the genome of an organism
    • This due to the large amount of post-translational modification of proteins (often in the Golgi apparatus)
    • Each gene is also capable of producing multiple different proteins via alternative splicing

Genome and Proteome, downloadable AS & A Level Biology revision notes

Image showing the increasing complexity of the proteome from the genome. Processes such as alternative splicing and protein modification enable the large number of proteins to be produced.

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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