Fungal Groups

• What are viruses composed of?

  DNA or RNA wrapped in a protein coat
• Why are viruses considered detached fragments of genetic material?

  They have evolved over time with protective coats
• Why do viruses pose a classification problem?

  They have both living and non-living features
• What are the "living" characteristics of viruses?

  • Composed of nucleic acids
  • Show inheritance and evolution
  • Studied by biologists with binomial names
• What classification problem do viruses pose?

  They have both living and non-living features
• What are the "living" characteristics of viruses?

  • Composed of nucleic acids
  • Show inheritance and evolution
  • Studied by biologists with binomial names
• What are the "non-living" characteristics of viruses?

  • Cannot reproduce independently
  • Genetic material is RNA or DNA
  • Not composed of cells
  • No metabolism of their own
  • Do not maintain homeostasis
  • Do not grow, assembled in mature form
• How are viruses best described?

  As 'active' or 'inactive'
• What are the "non-living" characteristics of viruses?

  • Cannot reproduce independently
  • Genetic material is RNA or DNA
  • Not composed of cells
  • No metabolism or homeostasis
  • Do not grow, assembled in mature form
• How many people did the 1918 influenza pandemic kill?

  20 – 50 million people
• How do viruses reproduce?

  They cannot reproduce independently of a host
• How do viruses survive outside of a host cell?

  They can survive but cannot reproduce
• How many deaths did HIV cause in 2018?

  1-2 million people
• What is the estimated death toll from Hepatitis in 2018?

  1.3 million people
• What is the impact of the 1918 influenza pandemic?

  It killed 20-50 million people worldwide
• How many deaths did Covid-19 cause by 2023?

  6.75 million people
• How many deaths did HIV cause in 2018?

  1-2 million people
• How many deaths from measles were reported in 2018?

  140,000 deaths
• What is the estimated death toll from Hepatitis in 2018?

  1.3 million people
• How many deaths did Covid-19 cause by 2023?

  6.75 million people
• What is the 'escaped gene theory' regarding viruses?

  Viruses evolved from rogue fragments of genetic material
• What do viroids consist of?

  Circular molecules of RNA without a protein coat
• What is the estimated death toll from measles in 2018?

  140,000 people, mostly children
• Why do scientists think viruses do not have a common ancestor?

  Most scientists believe in polyphyletic origin
• What is the 'escaped gene theory' regarding viruses' origin?

  Viruses evolved from rogue genetic material fragments
• What did Dmitri Ivanovsky discover about the tobacco mosaic virus?

  It remained infective after passing through filters
• What are viroids?

  Circular RNA molecules without a protein coat
• What is the significance of the 19th century in virus research?

  Biologists suspected viruses existed due to diseases
• What did Wendell Stanley find when he prepared an extract of TMV?

  It behaved as a chemical rather than an organism
• Why can't viruses be seen with a light microscope?

  They are smaller than 20-250 nm
• What is the basic structure of a virus?

  Nucleic acid core surrounded by a capsid
• What is a virion?

  The complete virus particle
• Why do viruses not fossilize?

  They are believed to lack a common ancestor
• What do glycoproteins on the viral envelope do?

  Bind to specific receptor molecules on host cells
• What is the basic structure of a virus?

  Nucleic acid core surrounded by a capsid
• How do some viruses enter host cells?

  By injecting genetic material or endocytosis
• What shapes can viruses have?

  Cylinder, sphere, polyhedron, or complex
• What types of nucleic acids can viruses have?

  DNA or RNA, single or double-stranded
• What is a virion?

  The complete virus particle
• What role do glycoproteins play in viruses?

  They bind to host cell receptors for entry