Viruses

Question 1

What is the genetic material of a virus

Answer 1

called its genome and can be made up of RNA or DNA

Question 2

what is a naked vs envaloped virus

Answer 2

Enveloped viruses typically have glycoproteins that protrode from the envelope important for attachment + entry

Question 3

what structure protects the genome in a virus and what is it made of

Answer 3

Capsied which is made of capsomeres

can be helical, polyhedral, bullet or spherical

Question 4

What is the nucleocapsid

Answer 4

Combo of capsid and genome together

Question 5

What is a + sense virus and - sense virus

Answer 5

Positive- can use their genomes to make proteins as soon as they are in host cytosol (mRNA)

Negative- RNA must first be converted to + sense by RNA dependent RNA polymerase before it can be translated

Question 6

What is a class 1 virus and ex

Answer 6

Ds DNA virus

herpes

Question 7

What is a class 2 virus and ex

Answer 7

ssDNA viruses

parvovirus

Question 8

What is a virus called that integrates itself into human genome

Answer 8

Provirus (usually DNA viruses can do this)

Question 9

What is a class 3 virus and ex

Answer 9

ds RNA virus

rotavirus

Question 10

What is a class 4 and 5 virus and exs

Answer 10

4- ss RNA (+)- hep a

5- ssRNA (-)- influenza, ebola

Question 11

What is a class 6 virus and what can they do

Answer 11

(+) ss RNA virus with reverse transcription step

The RNA can be converted to DNA then be inserted in the host dna

Question 12

What is a class 7 virus and what can they do

Answer 12

DNA virus with reverse transcription step
(hep b)

can integrate into human genome

Question 13

Hwo does a virus attach

Answer 13

Viral ligands bind to attachment receptors on target cell

Question 14

What are the 2 ways a virus can enter

Answer 14

Fusion- enveloped viruses can fuse w host cell plasma membrane

Receptor mediated endocytosis- Viral pro goes in via a endosome and then can fuse with the endosome membrane

Question 15

What is uncoating of a virus

Answer 15

Process where viral capsid pro deteriorate so viral genome can be released

Question 16

How does DNA and RNA viruses replicate in the host cell

Answer 16

DNA- in hosts cell nucleus
RNA- in cytosol

both use hosts nuclear import machinary

Question 17

How do viruses egress (leave)

Answer 17

via budding (uses host cell membrane), cell lysis (kills cell) or exocytosis (energy dependent)

Question 18

What are cytopathic effects

Answer 18

The damaged incurred by infection by virus

ex. holes in monolayer, rounding of infected cells etc

Question 19

lytic cycle of bacteriophage

Answer 19

Phage infects cell
virus dna multiplys and new phage particles made
Cell lyses releasing phages

Question 20

Lysogenic cycle of bacteriophage

Answer 20

phage infects cell
phage dna icorporates into host dna
as cell divides the phage dna is passed to offspring
(can move into lytic cycle after)

Question 21

What is susceptibility, permissivity and tropism

Answer 21

Susceptibility- refers to whether a virus can bind to a cellular receptor and enter cell

Permissivity- refers to ability to replicate in a cell

Tropism- range of cells susceptibe to infection