Prokaryotic Cells and Division

• What type of organisms are prokaryotes?

  Single-celled organisms
• What is an example of a prokaryote?

  Bacteria (like E. coli)
• What are the key structural features of prokaryotic cells?

  • Smaller and simpler than eukaryotic cells
  • No membrane-bound organelles
  • Cytoplasm contains smaller ribosomes
  • Cell-surface membrane made of lipids and proteins
  • Cell wall made of murein
• What is the function of the cell-surface membrane in prokaryotic cells?

  Controls movement of substances in and out
• What is the composition of the prokaryotic cell wall?

  Made of a polymer called murein
• What is murein?

  A glycoprotein in the cell wall
• What is the function of the flagellum in prokaryotic cells?

  Helps the cell move
• Do all prokaryotes have a flagellum?

  No, some have more than one
• Where is the DNA located in prokaryotic cells?

  Floats free in the cytoplasm
• What type of DNA do prokaryotic cells have?

  Circular DNA in one long strand
• What are plasmids in prokaryotic cells?

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

  Antibiotic resistance
• Are plasmids always present in prokaryotic cells?

  No, they are not always present
• What is the maximum size of prokaryotic cells?

  Less than 2 µm in diameter
• How do prokaryotic cells replicate?

  By binary fission
• 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 are produced
• How many times is the main DNA loop replicated during binary fission?

  Only once
• What are viruses classified as?

  Acellular entities
• What do viruses consist of?

  Nucleic acids surrounded by protein
• What is an example of a virus?

  HIV
• How do viruses replicate?

  By hijacking host cell machinery
• What are the steps of viral replication?

  1. Virus attaches to host cell
  2. Genetic material is released
  3. Host cell replicates viral components
  4. Viral components assemble
  5. Replicated viruses are released
• What do viruses use to attach to host cells?

  Attachment proteins
• Why can some viruses only infect specific cells?

  Due to different receptor proteins