Prokaryotes and viruses

• What type of DNA do all prokaryotic cells have?


  Naked circular DNA
• Where does the DNA in prokaryotic cells float?

  In the cytoplasm
• What type of ribosomes do prokaryotic cells have?


  Smaller ribosomes
• What is a key feature of prokaryotic cells regarding their membrane?

  They have a plasma membrane
• What is the composition of the cell wall in prokaryotic cells?


  Made of murein
• What are prokaryotic cells classified as?


  Microorganisms
• What is the function of pili in bacteria?


  To stick to host cells or other bacteria
• What is a plasmid?


  A loop of DNA
• What is the role of restriction endonuclease in recombinant DNA technology?


  To cut the plasmid backbone
• What happens when a staggered cut is made at the recognition site of DNA?


  Sticky ends are created
• What is required for sticky ends to combine?

  Same restriction enzyme must be used
• What forms when sticky ends combine?

  Recombinant DNA
• What can be done with recombinant DNA in bacteria?


  It can be replicated and proteins can be harvested
• How do prokaryotic cells divide?

  By binary fission
• What are the steps of binary fission in prokaryotic cells?


  1. DNA molecule replicates
  2. Two copies attach to different parts of the cell membrane
  3. Cell elongates and DNA pulls to opposite poles
  4. Septum forms dividing the cell
  5. Plasma membrane and cell wall materials accumulate around septum
  6. Cell pinches in two and splits
  7. Two identical daughter cells are formed
• How does binary fission differ from mitosis and meiosis?


  Binary fission does not involve a spindle apparatus or centrioles
• What do prokaryotic cells lack?


  A nucleus
• Do prokaryotic cells have membrane-bound organelles?


  No, they do not
• What structures do prokaryotic cells lack that are found in eukaryotic cells?


  Centrioles
• What is the primary difference between prokaryotic and eukaryotic cells?


  Prokaryotic cells are smaller and lack a membrane-bound nucleus, while eukaryotic cells are larger and have a membrane-bound nucleus.
• What are the main structures of a bacterial cell?

  • Cell wall
  • Capsule
  • Cell surface
  • Circular DNA
  • Plasmids
  • Ribosomes
• What is the role of the cell wall in bacteria?


  The cell wall acts as a physical barrier to some substances and protects against DNA damage.
• What is the role of the capsule in bacteria?


  The capsule is made of mucilage, providing protection against mechanical damage and promoting attachment to other cells.
• What is the role of the cell surface in bacteria?

  The cell surface is differentially permeable, controlling the entry and exit of chemicals.
• What is the role of circular DNA in bacteria?


  Circular DNA contains the genetic information necessary for the replication of bacteria.
• What is the role of plasmids in bacteria?


  Plasmids possess genes that may aid survival, such as enzymes to break down antibiotics.
• How is the organization of DNA different between prokaryotes and eukaryotes?


  Prokaryotic DNA is not associated with proteins, while eukaryotic DNA is associated with proteins called histones.
• How is the structure of DNA different between prokaryotes and eukaryotes?


  Prokaryotes have rings of DNA called plasmids, while eukaryotes do not have plasmids.
• How are organelles different between prokaryotes and eukaryotes?


  Prokaryotes do not have membrane-bound organelles, while eukaryotes do.
• How are photosynthetic organelles different between prokaryotic and eukaryotic cells?


  Prokaryotes contain chlorophyll in their membranes, while eukaryotes have chloroplasts (in plants and algae).
• How do ribosomes differ between prokaryotes and eukaryotes?


  Prokaryotes contain 70s ribosomes, while eukaryotes contain 80s ribosomes.
• How do cell walls vary between prokaryotes and eukaryotes?


  Prokaryotic cell walls are made of peptidoglycan in bacteria, while eukaryotic cell walls are made of cellulose in plants and are usually not found in fungi.
• How does the capsule vary from prokaryotes to eukaryotes?


  Prokaryotes have a mucilagenous outer layer, while eukaryotes do not.
• What is the typical size range of viruses?


  Viruses are generally between 20-300 nm.
• What is the basic structure of a virus?

  A virus is a cellular non-living particle composed of nucleic acid (DNA or RNA) contained within a protein coat called a capsid.
• Where do viruses reproduce?


  Viruses reproduce inside a host cell.
• How do different viruses allow for viral uptake?


  Viruses use attachment proteins to identify and attach to a host cell.
• Why do viruses not undergo cell division?


  Viruses do not undergo cell division because they are not living organisms.
• How do viruses replicate?


  Viruses replicate by attaching to a cell, injecting genetic information, and using the cell's metabolic reactions to create new viruses.
• What is the process by which viruses reproduce?


  Viruses reproduce only inside a host.