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Flashcards in Viruses Deck (7)
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What are viruses?

Nucleic acid contained within a protective protein coat. Can infect prokaryotes and eukaryotes.


What are the 2 main differences between viruses and bacteria?

1. Antibiotics have no effect 2. Cannot replicate outwith a cellular environment (obligate intracellular parasites; lack critical components for replication)


Label the parts that make up a virus:


A - genome

B - capsid

C - envelope

D - envelope glycoprotein


Describe the components of a virus

  1. Genome - viral nucleic acid
  2. Capsid - virus-encoded proteins. Protects genome and facilitates binding/entry of virus into cells
  3. Nucleocapsid - genome and capsid collectively
  4. Envelope - lipid bilayer derived from cellular membranes during replication in cell. Not all viruses have these.
  5. Envelope glycoproteins - Provide viral function, antigens recognised by immune system


What shape are viruses?


Icosahedral or helical


What are the features of an icosahedral virus?


  • 20 faces, faces are equilateral triangle
  • Some are enveloped eg. herpes virus
  • Some are not enveloped e.g. FMD


What are the features of a helical virus?

  • Simple
  • Small genomes
  • Provide protection for the genome without need to encode multiple capsid proteins