Eukaryotes and prokaryotes

• • cells of animals, plants and fungi are called eukaryotic cells
  • cells of bacteria are called prokaryotic cells
  • cells of bacteria do not have a nucleus
  • their DNA is present in the cytoplasm of their cells
  • it is found in a loop
  • bacteria can also have much smaller circles of DNA called plasmids
  • these are able to move from one cell to another
  • they provide genetic variation
• Eukaryotic cells

  • size = most are 5 μm – 100 μm
  • outer layers of cell = cell membrane - surrounded by cell wall in plants and fungi
  • cell contents = cytoplasm, cell organelles include mitochondria, chloroplasts in plants, and ribosomes
  • genetic material = DNA in a nucleus - plasmids are found in a few simple eukaryotic organisms
  • type of cell division = mitosis
• Prokaryotic cells

  • size = most are 0.2 μm – 2.0 μm
  • outer layers of cell = cell membrane - surrounded by cell wall
  • cell contents = cytoplasm, ribosomes - no mitochondria or chloroplasts
  • genetic material = DNA is a single molecule, found free in the cytoplasm - additional DNA is found in one or more rings called plasmids
  • type of cell division = binary fission
• Archaea

  • microorganisms which are similar in size and structure to bacteria but are genetically different
  • prokaryotic