viruses

• How do prokaryotic cells compare in size to eukaryotic cells?

  Prokaryotic cells are much smaller than eukaryotic cells
• What is the size range of virus particles?

  From around 20 nanometers to around 300 nanometers
• Why can viruses not reproduce independently?

  Because they can only reproduce inside a host cell
• What is the first step in the life cycle of a virus?

  A virus particle attaches to the surface of a host cell
• What does a virus use from the host cell to reproduce?

  The host cell's enzymes
• What happens to virus particles after they reproduce inside a host cell?

  They leave the host cell to infect new host cells
• What is contained inside a typical virus particle?

  Genetic material, which can be either DNA or RNA
• What is the protein structure that contains the genetic material of a virus called?

  Capsid
• What role do attachment proteins play in a virus?

  They allow the virus particle to attach to and enter the host cell
• What is a lipid envelope in some viruses formed from?

  The host cell membrane
• How do scientists classify viruses in terms of cellular structure?

  Viruses are classified as acellular
• Why do scientists not count viruses as living organisms?

  Because they cannot reproduce independently
• What are the key structures found in all viruses?

  • Genetic material (DNA or RNA)
  • Protein structure (capsid)
  • Attachment proteins
  • Lipid envelope (in some viruses)
• What is the life cycle of a virus?

  1. Virus attaches to host cell
  2. Virus enters host cell
  3. Virus uses host cell's enzymes to reproduce
  4. New virus particles leave the host cell to infect new cells