65/66 Intro to Virology

Question 1

a complete virus particle is called a what?

Answer 1

virion

Question 2

nucleic acid surrounded by the protein coat is what?

Answer 2

caspid (formed from identical protein subunits = caspomeres)

Question 3

4 general forms of human viruses?

Answer 3

1. protein iscosahedron (naked caspid)
2. protein icosahedron enclosed by lipid-protein envelope (derived from cell membrane)
3. helical protein coil enclosed by lipid protein envelope
4. complex (poxvirus)

Question 4

is the naked icosahedral caspid stable or labile?

Answer 4

stable - can spread easily

Question 5

are enveloped viruses stable or labile?

Answer 5

labile - disrupted by acid/deterents/drying/heat

Question 6

DNA viruses?

Answer 6

herpseviridae
hepadnaviridae
papillomaviridae
polyomaviridae
adenoviridae
parvoviridae
poxviridae

Question 7

major difference between -ssRNA and +ssRNA viruses?

Answer 7

-ssRNA must carry TNA pol in virus

Question 8

major steps in viral replication?

Answer 8

1. recognition
2. attachment
3. penetration (entry)
4. uncoating
   5 macromolecular synthesis
   a. early mRNA and early regulatory proteins
   b. genome replication
   c. late mRNA and structural proteins
   d. post-translational modification of proteins
5. assembly
6. budding (if enveloped)
7. release

Question 9

VAP re: viral replication?

Answer 9

binding of virus attachment protein (VAP) to cellular receptor is a passive, kinetic process

enveloped viruses have VAPs, termed envelop proteins or spike proteins on the envelope surface

non-enveloped viruses have VAPs on the caspid, usu at most exposed points

Question 10

eclipse period of viral growth?

Answer 10

entering virus disassembled, new virions not yet observable

Question 11

MOI?

Answer 11

multiplicity of infection = ratio of infectious virus units (PFU) to cells at START

Question 12

latent period re: viral growth?

Answer 12

time before any virus released

Question 13

burst size?

Answer 13

ratio of infectious virus particles RELEASED (PFU) to cell number

Question 14

adenovirus?

Answer 14

dsDNA genome

naked icosahedral

respiratory tract infections, conjunctivitis, hemorrhagic cystitis, and gastroenteritis

lots of serotypes

Question 15

poxvirus?

Answer 15

dsDNA genome

large, complex structure w/cytoplasmic replication

smallpox (variola virus) and smallpox vaccine (vaccinia virus)