AQA AS Biology

Revision Notes

4.1.1 Prokaryotic DNA

DNA in Prokaryotes

  • The DNA in prokaryotic cells is significantly different from the DNA found in eukaryotic cells
  • “Prokaryote” means “before the nucleus”
  • The DNA is double-stranded
  • Prokaryotes possess a single, circular chromosomal DNA molecule
    • It is sometimes referred to as a nucleoid
  • They also usually have one or more plasmids
    • Plasmids are very small circular DNA molecules
    • They usually only contain a few genes
    • Plasmids are more accessible for proteins required for gene expression and therefore contain genes that are required often, quickly and/or in emergencies
    • The genes for antibiotic resistance are often found in plasmids
  • The DNA within prokaryotic cells is not associated with any proteins
    • Eukaryotic DNA associates with histone proteins

Prokaryotic DNA, downloadable AS & A Level Biology revision notes

Image showing the arrangement of DNA within a prokaryotic cell.

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.
Close

Join Save My Exams

Download all our Revision Notes as PDFs

Try a Free Sample of our revision notes as a printable PDF.

Join Now
Already a member?
Go to Top