DifferencesProkaryotes are much smaller than eukaryotic cells. Prokaryotic cells are 0.5-5 microns in diameter compared to eukaryotic cells which are approx 50-100 microns. Another difference is that prokaryotes do not have a nucleus but all eukaryotes do. Prokaryotes use circular DNA plasmids whereas eukaryotes use linear chromosomal DNA. Prokaryotic ribosomes are smaller than eukaryotic ribosomes.
SimilaritiesThey both use DNA to store the genetic code and share the central dogma of biology: e.g. DNA --> RNA --> Protein. Pro- and Eukaryotes both use the same codons within DNA. In both ATP is used as the universal energy currency. RNA is translated into proteins in the cytoplasm in both, prokaryotes and eukaryotes. Both have access to the same 20 naturally occurring amino acids, and often use the same enzyme cofactors, such as: Iron Ions or Acetyl-CoEnzyme A.