virus & prions

Question 1

what are general properties of viruses?

Answer 1

small, RNA or DNA genome, metabolically inert- no ribosomes/protein synthesis, some have enzymes

Question 2

what is a capsid?

Answer 2

protein shell made up of capsomers

Question 3

what is an envelope?

Answer 3

lipid membrane around some viruses

Question 4

what are the 5 modes of virus transmission?

Answer 4

inhalation-resp. tract
ingestion-GIT
inoulation-abrasion, mucous membranes, tranfusions, transplants, injections, bites
congenital-mother to fetus
sexual transmission

Question 5

what are 3 effects of a virus on a cell?

Answer 5

cell death-cytopathic effect
transformation- cancerous
latent infection- remain in cell with no obvious effect

Question 6

what are the 6 stages of wiral replication?

Answer 6

attachment, penetration, uncoating, synthesis of viral components, assembly, release

Question 7

what is antigenic drift?

Answer 7

minor change- point mutations, epidemics, type A,B and C

Question 8

antigenic shift

Answer 8

major change, recombination, pandemics, only type A

Question 9

what are the 6 links in the chain of infection?

Answer 9

the infectious agent
the reservoir
the portal of exit
the mode of transmission
the portal of entry
the susceptible host

Question 10

what is a prion?

Answer 10

infectious agent devoid of nucleic acid

Question 11

what is a prion disease due to?

Answer 11

accumulation of abnormal form of natural protein