Module 7

Question 1

when were viruses first identified
with what disease

Answer 1

1892
tobacco mosaic disease

Question 2

5 characteristics of viruses

Answer 2

genetic element in protein shell (capsid)
DNA or RNA not both
double, single stranded
segmented or non segmented
naked or enveloped

Question 3

why are viruses not considered to be living

Answer 3

do not have cellular components/metabolism
fully dependent on host for energy and protein synthesis

Question 4

name of the extracellular form of a virus

Answer 4

viron

Question 5

type of microscopy to see viruses

Answer 5

TEM

Question 6

viral genome components

Answer 6

dna or rna
1000-2.5 mega base pairs
7-1000 proteins

Question 7

capsid

Answer 7

made up of 1 or more protein subunits called capsomeres
can be self assembling or require host involvement

Question 8

2 primary symmetrical shapes of viruses

Answer 8

rod with helical symmetry
spherical with icosahedral symmetry

Question 9

what is width and length dependent on in helical symmetry

Answer 9

width: size/packaging of capsomeres
length: nucleic acid strand length

Question 10

icosahedral symmetry geometry

Answer 10

20 triangular faces and 12 vertices
simple and most effective assembly

Question 11

example of a complex virus shape

Answer 11

icosahedral head with helical tail
complex means no symmetry

Question 12

naked virus components

Answer 12

capsid
nucleic acids

Question 13

enveloped virus components

Answer 13

membrane
capsid
nucleic acids

Question 14

how are phospholipid layers derived in viruses

Answer 14

from host during exocytosis

Question 15

fibrils

Answer 15

peptidoglycan like polymers on amoeba viruses

Question 16

spike proteins

Answer 16

on the surface of viruses
one type to bind
one type to release

Question 17

enzymes in bacteriophages

Answer 17

lysozyme like
cut away enzyme to get new DNA in

Question 18

enzymes in RNA viruses

Answer 18

replicate RNA without template

Question 19

enzyme in retroviruses

Answer 19

reverse transcriptase (RNA–>DNA)

Question 20

why are viruses not on the tree of life

Answer 20

they do not have rRNA

Question 21

writing virus names

Answer 21

species is italic
viral is not italic

Question 22

name of virus classification system

Answer 22

baltimore classification

Question 23

factors affecting how a virus infects a host

Answer 23

host
baltimore classification
type (naked/enveloped)

Question 24

process of phage infecting bacteria (five)

Answer 24

attachment (binding to specific surface receptors)
penetration (viral DNA enters host cell)
biosynthesis (phage DNA replicates, phage proteins are made)
maturation (new phage particles assembling)
lysis (cell lyses releasing baby phages)

Question 25

steps of a one step growth curve (three)

Answer 25

inoculation (binding) eclipse ( virions penetrate the cell) burst (host cell releases viral particles)

Question 26

burst size

Answer 26

number of virions released per bacterium

Question 27

what type of viruses exhibit a one step growth curve

Answer 27

lytic viruses as they lyse out all at once

Question 28

gram + receptors

Answer 28

flagellum PIP CWPS LTA WTA

Question 29

gram - receptors

Answer 29

flagellum pili porin LPS CPS EPS

Question 30

infection process of temperate phages into bacteria (four decriptive steps)

Answer 30

phage infects bacteria phage DNA incorporated cell divides and passes on incorporated DNA prophage DNA is excized under stress so it can spread

Question 31

what is a lysogen

Answer 31

bacteria with a phage integrated into its bacterial genome or as a plasmid

Question 32

what is lysogenic/phage conversion

Answer 32

phage changes the bacteria's (lysogen's) phenotype

Question 33

viral infection of eukaryotes process (six steps)

Answer 33

attachment (virus binds to target cell) penetration (cell engulfs virus through endocytosis) uncoating (viral content is released inside the cell) biosynthesis (viral RNA enters nucleus, replicated) assembly (new phage particles made) release (viral particles are released without killing the cell)

Question 34

lytic infection

Answer 34

cell must be lysed to release

Question 35

types of persistent infection, describe

Answer 35

latent-virus is dormant and reactive to stimuli chronic-virus is not eliminated, continuous production

Question 36

types of cancer infections, describe

Answer 36

direct-inactivation of safeties indirect- chronic infection

Question 37

antigenic drift

Answer 37

change in some of the spike proteins

Question 38

antigenic shift

Answer 38

combination of two viruses spike proteins to make a new virus

Question 39

how do viruses acquire their envelopes

Answer 39

during the release phage while budding off

Question 40

in order to grow viruses you need

Answer 40

living host cell host cell type that support infection (receptor) conditions to grow host quantification of virus (plaque for lytic virus)

Question 41

plaque is only found

Answer 41

in lytic viruses

Question 42

how to quantify number of viral genome in a cell without a microscope

Answer 42

qPCR

Question 43

in DNA the positive strand is the negative strand is

Answer 43

+: sequence=mRNA, cant be translated -: sequance to use as a template to make an mRNA sequence

Question 44

in RNA the positive strand is the negative strand is

Answer 44

+: template for translation -:cannot be template

Question 45

in DNA you need ___ strand to make mRNA

Answer 45

negative

Question 46

in RNA you need ___ strand to make protein

Answer 46

positive

Question 47

BC1

Answer 47

double stranded DNA virus

Question 48

BC2

Answer 48

single stranded DNA virus

Question 49

BC3

Answer 49

double stranded RNA virus

Question 50

BC4

Answer 50

positive sense RNA virus

Question 51

BC5

Answer 51

negative sense RNA virus

Question 52

BC6

Answer 52

reverse transcribing RNA viruses

Question 53

dsDNA virus processes

Answer 53

go through replication go through transcription (neg temp, pos mRNA), translation

Question 54

ss DNA virus process

Answer 54

must replicate first then can replicate or go through transcr and transla

Question 55

dsRNA virus process

Answer 55

go through replication go through transcr, transla

Question 56

+ sense RNA virus process

Answer 56

pos strand replicates, replicates again pos strand can go through translation

Question 57

-ve sense RNA virus process

Answer 57

neg strand can replicate x2 neg stand can transcribe then translate

Question 58

reverse transcribing RNA virus process

Answer 58

goes through reverse transcription then replication after, it can replicate or go through transcr and transla