Prokaryotes vs. Eukaryote Cells

Prokaryotic cells

  • Prokaryotes are the most ancient forms of life on Earth, including true bacteria and the archaebacteria (now called archaea)

  • These cells lack organelles, but they have circular DNA

  • Size: Very small; 0.1 – 10 μm, or 10x smaller than eukaryotic cells

  • Diversity: Unknown number of species; maybe a few thousand to a million

  • Major groups (see below for groups covered in BOT III: Plant Diversity)

Prokaryotic Groups

Eukaryotic cells

  • Eukaryotes appeared around 2 billion years ago, as simple algae

  • These cells have membrane-bound organelles present, including a nucleus

  • Size: Small, but not nearly as small as prokaryotes; 10 – 100 μm long

  • Diversity: 7 – 10 million species

  • Major groups (see below for groups covered in BOT III: Plant Diversity)

Eukaryotic Groups

  • Archaeplastida: plants, red algae, and green algae

  • Chromalveolates: water molds, diatoms, brown algae and dinoflagellates

  • Excavates: Euglena, Giardia

  • Unikonts: fungi, animals, slime molds

What about viruses?

  • Viruses don't have cells, but learn more about them here