Chapter 13 Exam 2

lysozyme, phage, 200

In the final stage, release, ____ digests the cell wall and releases _______ in a burst size (T4=)

degrades the host cells DNA host cells RNA polymerase

In the third stage, synthesis early proteins are 1. a nuclease that _____ and 2. proteins that modify ____

PrPc

cells produce normal form of prions

lysogenic conversion

change in the phenotype of a lysogen as a consequence of genetic material being carried by a prophage

type of nucleic acid, shape of virus, host infected and strandedness of nucleic acid

classification of viruses can be based on all of the following

nucleocapsid

complete complex of nucleic acid and protein packaged in the virion

viron

complete virus in its inert non-replicating form; also referred to as a viral particle

chronic infection

continuous, low-level production of new virus particles by animal host cells aka a person can transmit the virus to others in the absence of symptoms ex. Hep B

DNA, RNA or reverse transcribing viruses

in animal virus replication, there are 3 strategies for replication, what are they?

pores

in the fourth step of the filamentous phage cycle what do the other proteins form?

lysogen

infected host cell

PrPsc

infectious prion proteins

envelope

lipid layer

viral, chromosome

lysogeny is integration of the ____ genome into the host _____

hijack host

main goal of early proteins

plaque assay

method to determine the number of viral particles in a suspension using a monolayer of tissue culture cells, clear zones around uninfected cells are counted

naked virus

nucleocapsid that lacks envelope and is more resistant to disinfectants

endocytosis

plasma membrane surround the virion, forming a vesicle and the vesicle then releases

neural, neurons

prion proteins accumulate in _______ tissue: causing ____ to die

proteinaceous, protein

prions are _____ infectious agents composed solely of ___

apoptosis

programmed cell death, triggered by naked viruses

so it will not recognize its own promoters

purpose of the early protein that modifies the host cells RNA

transmissable spongiform encephalopathies

refer to all prion diseases because of their spongelike appearance of brain tissue

fusion

virus fuses with plasma membrane, naked viruses cannot use this process for entry

nucleocapsid, envelope, host attachment

enveloped viruses are a _____ enclosed in a ____ in a lipid layer with spikes that help with ______

1. template for mRNA 2. copies of genome

in the filamentous phage cycle, what are the complementary DNA strands used for

pores, coat, nucleocapsids

last step of the filamentous phage cycle involves phage DNA being excreted through ______, proteins ______ the DNA and form _________

prophage

latent form (integrated but doesnt cause disruption) of a temperate phage whose DNA has been inserted into the host's DNA

prions

linked to slow fatal human/animal diseases

partial immunity

lysogen is immune to superinfection; infection by same phage or similar

endocytosis

naked virus must use ____ to enter an animal cell because they have no lipid envelope and therefore cannot fuse to host membranes

nucleocapsid, disinfectants

naked viruses are a _____ only and are more resistant to ____

enveloped virus

nucleocapsid that has envelope

virus

obligate intracellular parasites, infectious agents but not alive

bacteriophages

only ___ trigger cell lysis by the production of a phage-encoded lysozyme

chronic, latent

persistent infections can either be ____or _____

prophage

phage DNA that is latently incorporated into the bacterial host genome

lytic phage

phage exits host and host is lysed (dies); a productive infection

capsid

protein coat that determines that determines the shape of a virus

infectious prion

resistant to proteases; become insoluble, aggregate; usually resistant to heat, chemical treatment

filamentous phage

single-stranded DNA phages that cause productive infections but the host cells are not killed by lysis (grow more slowly)

1. attachment 2. genome entry 3. synthesis of proteins and genome 4. assembly 5. release

stages of lytic phage

1. attachment 2. penetration and uncoating 3. synthesis 4. assembly 5. release

steps of animal virus replication

size

viruses are NOT classified according to?

nuclease to digest the host DNA protein that modifies host RNA polymerase

what are the early viral proteins produced in the T4 lytic cycle?

1. T4 capsomers 2. T4 tail fibers

what are the late viral proteins produced in the T4 lytic cycle?

1. acute 2. persistant

what are the two categories of animal virus infections?

integrate their genomes into the host genome

what can temperate (lysogenic) phages do that lytic phages cannot?

lytic infection

what does excision of a repressor protein in the lysogenic state result in?

inaccurate excision

what mistake in temperate phage replication cycle leads to specialized transduction?

packaging error of phage incorporating fragments of host DNA

what mistake leads to generalized transduction?

1. attachment 2. assembly 3. genome entry 4. release 5. biosynthesis of viral components

what steps do both temperate and lytic phages have?

tail fibers, bacterial receptors, cell wall

In the first stage (lytic) attachment, phage ___ ____ bind to ___ _____ on _____ ______ ex. T4

maturation, protein scaffolds

In the fourth stage, assembly or ____ some components spontaneously assembly while others require ___

fusion or endocytosis

In the penetration and uncoating step of an animal virus, what are the two ways of entry?

lysozyme, tail, genome

In the second stage (lytic), genome entry, phage enzyme ____ degrades the cell wall, ___ contracts to inject the _____

structural, capsid and tail

In the third stage (lytic), synthesis of late proteins that are ____ ; make up the ___ and ___ are synthesized

proteins, genome

In the third stage (lytic), synthesis of phage _____ and ______

replicates

a temperate phage takes the lysogenic path: the prophage now ______ with host chromosome

lyse, phages

a temperate phage takes the lytic path: lastly, the cells _____ , releasing new_______

lambda, attaches

a temperate phage takes the lytic path: phage _____ first ______ to a bacterium

linear, circularizes

a temperate phage takes the lytic path: second, the phage injects _____ phage DNA, it ______ and enter lytic cycle

replicates, synthesizes

a temperate phage takes the lytic path: third, the phage DNA ______ and ______ phage-encoded proteins

tumor

abnormal cell growth

partial immunity and lysogenic conversion

advantaged of temperate phage (2)

uncoating

after a virus enters the host cell, the nucleic acid separates from its protein coat

latent infection

after initial infection the viral genome can remain silent as a provirus (cannot be eliminated) and be reactivated later ex. cold sores

1. have their nucleic acid enter the host cell 2. have their nucleic acid replicate in the host cell

all phages must have the ability to do what two things?

phage induction

allows phage to escape damaged host

lysogenic infection

an infection that results in the integration of bateriopahge DNA into the chromosome of a bacterial host, no new particles are made

nucleus

animal DNA viruses replicate within the host cell's ____

surface proteins

antigenic drift occurs when mutations accumulate encoding for ___ ___ that can be recognized by the immune system; can result in a person being susceptible to a new variant arising later

segmented, reassortment

antigenic shift results when a ____ virus undergoes ____

lysogeny

bacteria that has prophage integrated into its chromosome

preventing phage attachment

bacterial defense in which bacteria can alter or cover its surface receptors to prevent infection ex. S. aureus makes protein A to cover phage receptors

viral oncogenes

can interfere with host control mechanisms and stimulate cell growth and tumor inducing

1. either DNA or RNA 2. linear, circular or fragmented 3. double or single-stranded

3 characteristics of a nucleic acid

1. icosahedral 2. helical 3. complex

3 shapes of viruses

1. lytic phage 2. temperate phage 3. filamentous phage

3 types of bacteriophages due to host relationship

DNA: DNA polymerase RNA: replicase RT: reverse transcriptase

DNA, RNA and RT, replicase or transcriptase?

HIV, reverse transcriptase

___ is described as a retrovirus because it replicates its RNA genome by using ____ ____ to produce a DNA intermediate

helical, icosahedral

___ viruses have capsomers arranged to form long cylinders, while capsomers of _____ viruses are arranged as a multifaceted, polygonal capsid

proto-oncogenes, tumor suppressor

___-____ and ____ ___ genes work together to stimulate or inhibit growth and cell division of a tumor

PrPsc, PrPc

_____ converts ______ folding to PrPsc

Creutzfeldt-Jakob disease, Bovine spongiform encephalopathy

______ and _________ are examples of prion-related diseases

repressor protein

_______ ________ maintain lysogenic state of the temperate phage

integrase

______directs the incorporation of phage DNA into a bacterial chromosome

temperate

a _____ phage is a bacteriophage that incorporates its DNA into the host genome as a prophage

protease

a phage-encoded enzyme that destroys repressor protein; allows prophage to be excised

DNA, chromosome, latent

a temperate phage takes the lysogenic path: after attaching and injecting phage DNA that circularizes, the phage______ integrates into host ________ by site specific recombination. The cell remains _______.

M13

filamentous phage (extrusion) uses ______ phage as a model

protein, F pili

first step of the filamentous phage cycle involves attachment to ______ on __ ______ of bacteria (E. Coli)

coat, cytoplasmic membrane

fourth step of the filamentous phage cycle involves m13 phage ______ protein molecule inserted into host __________ ____________

protease

how can a repressor protein be excised?

budding

how do most animal viruses release?

capsomers

identical subunits that compose capsids and determine the shape of a virus

type of genome of virus

in animal virus replication, there are 3 strategies for replication based on what?

RNA, DNA

reverse transcriptase uses a ____ molecule to make a complementary strand of _____

single stranded, cytoplasm

second step of the filamentous phage cycle involves _______ _________ DNA genome entering the _________

lytic, lysogenic, lambda

temperate phages can either be ____ or ____ and model phage is:

polymerase, complementary

third step of the filamentous phage cycle involves DNA ________ (of host) synthesizes _________ DNA strands for M13

plaque assays

used to quantitate phage particles in samples

spikes

viral glycoproteins that stick out from the viral envelope and attach to host cell receptors in an animal virus