Virology

Question 1

What are some examples of common viruses ?

Answer 1

• ebola
  -HIV
• rabies
• SARS
• influenza

Question 2

Describe Viruses

Answer 2

• not cells, no organelles
• parasites
• small genomes
• inert outside of host

Question 3

What are some examples of virus transmission?

Answer 3

• respiratory route
• faecal-oral route
• sexual
• breach in the skin
• vector-borne

Question 4

How do viruses replicate ?

Answer 4

1. attachment to host cell
2. entry into host
3. transcription of viral genome
4. translation of viral mRNA into protein
5. genome replication
6. assembly of virus particles
7. released from host cell

Question 5

How do viruses attach ?

Answer 5

• binding by hydrogen bonds, ionic attractions and van Der Waals forces

Question 6

Where does attachment occur in viruses ?

Answer 6

between virus structures, such as spikes, knobs or glycoproteins and cell surface receptors

Question 7

What occurs during viral translation ?

Answer 7

• generates proteins for ; viral assembly (capsid proteins, spikes & scaffolding proteins)
  -packaging within virion (enzymes)

Question 8

How do viruses assemble ?

Answer 8

• simple virions may self-assemble
• larger virions assembled using scaffolding proteins

Question 9

How do viruses exit cells?

Answer 9

• enveloped virions –> virus capsid directed to modified membrane and buds off cell surface
• cell is left intact
• some leave via lysis of host cell

Question 10

What is the 1st category of diagnostic test ?

Answer 10

• Direct detection

Question 11

What are some examples of direct detection testing ?

Answer 11

• electron microscopy
• antigen protection
• direct detection of viral genomes (PCR)

Question 12

What is the 2nd category of diagnostic test ?

Answer 12

indirect detection
- example = cell culture - enumeration

Question 13

What is the 3rd category of diagnostic test ?

Answer 13

Serology

Question 14

Describe serology

Answer 14

• detection of antibody (using antigens)
• IgM in primary infection
• I gG in past or chronic infection

Question 15

What are some uses of viruses ?

Answer 15

• phage typing of bacteria
• sources of enzymes
  -pest control
• antibacterial
• gene therapy

Question 16

What are the main classes of antivirals ?

Answer 16

1. fusion inhibitors
2. reverse transcriptase inhibitors
3. nucleoside analogues
4. protease inhibitors
5. neuraminidase inhibitors

Question 17

What are some types of vaccine?

Answer 17

• live attenuated vaccines
• toxoids
• subunit vaccines
• inactivated vaccines
• recombinant/DNA vaccines
• mRNA vaccines