Prokaryotic cells and viruses

• What are prokaryotic cells different from?

  Eukaryotic cells
• What is a key structural difference between prokaryotic and eukaryotic cells?

  Prokaryotic cells lack membrane-bound organelles
• What is the structure of a prokaryotic cell?

  • Single-celled organisms
  • No nucleus
  • No membrane-bound organelles (except mesosome)
  • Cell wall made of peptidoglycan
  • DNA floats freely in cytoplasm
• What is the main component of the prokaryotic cell wall?

  Peptidoglycan
• What is murein in prokaryotic cells?

  A glycoprotein associated with carbohydrates
• What is the function of the flagellum in prokaryotic cells?

  Enables movement
• Do all prokaryotic cells have a flagellum?

  No, some have more than one
• How is the DNA arranged in prokaryotic cells?

  One long circular strand
• What is the role of the capsule in some prokaryotes?

  Protects from immune system attacks
• What are plasmids in prokaryotic cells?

  Small loops of DNA
• What can plasmids contain genes for?

  Antibiotic resistance
• How small are prokaryotic cells?

  Less than 2 μm in diameter
• How do prokaryotic cells compare in size to eukaryotic cells?

  Prokaryotic cells are much smaller
• What are the learning objectives regarding prokaryotic cells?

  • Smaller than eukaryotic cells
  • No internal membrane-bound organelles
  • Single circular DNA molecule and plasmids
  • Cell wall contains murein
  • May have plasmids, capsule, and flagella
• What is the process by which prokaryotic cells reproduce?

  Binary fission
• What happens during binary fission?

  DNA and plasmids replicate before division
• What are the steps of binary fission in prokaryotic cells?

  1. Circular DNA and plasmids replicate
  2. Cell enlarges, DNA moves to poles
  3. Cytoplasm begins to divide
  4. Two daughter cells form
• What are viruses classified as?

  Acellular and non-living
• What is the basic structure of a virus?

  Nucleic acid surrounded by protein
• How do viruses replicate?

  Host cells replicate virus particles
• What is a capsid?

  A protein coat of a virus
• What is the role of viral attachment proteins?

  They help viruses cling to host cells
• How do viruses compare in size to bacteria?

  Viruses are smaller than bacteria
• What are examples of viruses?

  • HIV (causes AIDS)
  • Influenza (causes flu)
  • Rhinoviruses (cause colds)
• What is the function of the immune system in relation to bacteria?

  Attacks bacteria
• What is the significance of plasmids in prokaryotic cells?

  They can be passed between prokaryotes
• How does the replication of viruses differ from that of prokaryotic cells?

  Viruses use host cells for replication