Prokaryotes, eukaryotes and viruses

• Organisms containing cells that have membrane-bound organelles, with the DNA in chromosomes within the nucleus

  Eukaryotes
• Single-celled organisms lacking membrane-bound organelles, such as a nucleus, with its DNA free in the cytoplasm

  Prokaryotes
• Not made of cells (acellular), have no organelles, no chromosomes and no cytoplasm, can only replace using a host cell

  Virus
• Typical features of a prokaryote ...

  1. Small cells
  2. 70S ribosomes
  3. No membrane bound organelles
  4. DNA free in cytoplasm
  5. No nuclear envelope
  6. Plasmids are present
  7. Peptidoglycan cell wall
  8. No mitochondria, instead use a mesosome which is a folded region of the cell membrane
• Typical features of a eukaryote ...

  1. Larger cells
  2. 80S ribosomes
  3. Membrane bound organelles are present
  4. DNA contained within the nucleus
  5. Nucleus has a double membrane
  6. No plasmids
  7. If the cell wall is present, it is composed of cellulose
  8. Mitochondria are used for aerobic respiration
• Structure of a virus ...

  1. Contains a capsid which is a protein coat
  2. Nucleic acid contains genetic material