Virus Structure And Classification

Question 0

3 basic gene modules

Answer 0

Capsid proteins
Replicon (encodes nucleic acid polymerase and accessory proteins to copy genome)
Multifunctional proteins that interact with host (not packaged into virion)

Question 1

Properties of viruses

Answer 1

Bit bigger than ribosomes
Associated with all life forms so no evolutionary tree, high genetic diversity
Obligate intracellular parasites

Question 2

Capsid structure

Answer 2

Protein shell encapsulating nucleic acid genome
Helical symmetry
Icosahedral symmetry

Question 3

Virion structure

Answer 3

Particle encoded by a virus genome
Infected host is virus
All virions have capsids but only some have envelopes (from host lipid bilayer)

Question 4

Virus classification

Answer 4

Host cell kingdom (euk 'plant, insect animal' or prok)
Genome type (RNA or DNA, single or double stranded)
Virion structure (enveloped or naked, helical, icosahedral or complex)

Question 5

Virion components

Answer 5

Nucleocapsid: core of nucleic acid and protein coat (capsid)
Tegument: mix of viral and host proteins between envelope and capsid to use to infect cells (Herpes)
Matrix: within capsid
Glycoprotein: embedded in envelope, glycosylated
Spike/fiber: not embedded, not glycosylated