Lecture 1: Intro and classifications

Question 0

what are the 5 main ways of classifying viruses?

Answer 0

1. virion architecture (nucleocapsid size, shape and symmetry) (enveloped vs naked)
2. nucelic acid and replication strategies
3. phylogenomics
4. antigenic relationships (serology)
5. biologic characteristics

Question 1

Koch’s postulates

Answer 1

1. agent must be present in every case of the disease
2. agent must be isolated from the host and grown in vitro
3. the disease must be reproduced when the pure cultivated agent is introduced into a healthy susceptible host
4. the same agent must once again be recoverable from the newly infected host

Question 2

virion =

Answer 2

completed infectious virus particle

Question 3

nucleocapsid

Answer 3

nucleic acid core enclosed in protein

Question 4

envelope

Answer 4

glycoprotein studded phospholipid membrane

Question 5

are enveloped viruses more or less fragile than non-enveloped viruses?

Answer 5

MORE!

Question 6

what are 2 examples of a symmetrical nucleocapsid?

Answer 6

icosehdral

helical

Question 7

what are 3 examples of a non-symmetrical nucelocapsid shape?

Answer 7

complex, filamentous, pleomorphic

Question 8

class I viruses

Answer 8

dsDNA genome

Question 9

class II

Answer 9

ssDNA genomes

Question 10

class III

Answer 10

dsRNA genomes

Question 11

class IV

Answer 11

ssRNA(+) genomes

Question 12

class V

Answer 12

ssRNA(-) genomes

Question 13

class VI and VII

Answer 13

reverse transcriptase

exist as RNA being able to change into DNA

Question 14

what is phylogenomics?

Answer 14

genomic sequencing

Question 15

antigenic relationships

Answer 15

the grouping of viruses into different subtypes or serotypes based on the host antibody response to various antigenic viral proteins

vaccination with one subtype (serotype) is unlikely to protect against others

Question 16

what are the categories used for grouping viruses based on biological properties?

Answer 16

enteric viruses
respiratory viruses
arboviruses
oncogenic viruses

Question 17

what does arboviruses mean?

Answer 17

“ARthropod-BOrne viruses” = arboviruses

viruses that undergo a natural vector-vertebrate-vector cycle

Question 18

generalized viral life cycle

Answer 18

attachment –> penetration –> uncoating –> replication –> transcription –> translation –> assembly –> release

Question 19

what are viral induced cellular changes

Answer 19

necrosis and apoptosis (cytopathic effect - observable degenerative changes in the cell)
cell transformation (to a cancerous state)
no discernible effect