MCB 4503 Exam 1 (EU)

Identify which group(viral genome) is being described: i. The DNA must be converted into double stranded DNA ii. then cellular enzymes can do their normal thing and convert that into mRNA

(+)ssDNA

Which of the viral genomes have to go through some intervening step before the nucleic acid can be converted into messenger RNA

(+)ssDNA, (+)ssRNA(retroviruses), (+/-)dd/ssDNA

Identify which group(viral genome) is being described: i. Their genomes can actually be used as messenger RNA ii. Can be immediately translated once it is inside the cell

(+)ssRNA

Identify which group(viral genome) is being described: i. Don't use their nucleic acid as messenger RNA ii. Go through the process of reverse transcription, convert their RNA into DNA, and then that DNA gets converted back into messenger RNA

(+)ssRNA (retroviruses)

Which statement about viral RNA genomes is correct? Copying of (+)ssRNA during virus replication does not require a (-) strand intermediate (+)ssRNA genomes may be translated to make viral protein RNA genomes can be copied by host cell RdRp dsRNA genomes can be directly translated to make viral protein

(+)ssRNA genomes may be translated to make viral protein

mRNA is always + or -

+

Terms -mRNA is always the ___ strand -The DNA strand that is of equivalent polarity to mRNA is the ___ strand -mRNA can be translated by ____ into protein without any alteration

+ + ribosome

*flavivirus: dengue* -Entry: RME, => e____, viral rna enters c_________ -surface/cell receptors: c______ receptor, f____ receptor -what cells targeted? -*UNIQUE*: replicates on membrane vesicles of the e____ _______ -B cells fight Dengue, but they can actually make later infections worse bc of mutated dengue strains

-endosome -cytoplasm -cognate -fc -targets immune -ER

*Retrovirus steps* -enter through _________ -In the cytoplasm, ________ ________ transforms rna => dna -enters the ____, integrates into host genome using i_____ -integrase chops off bases at the end of viral dna -inegration into the host genome (can happen anywhere/is cite directed) -can integration be reversed?

-fusion -reverse transcriptase -nucleus -integrase -can happen anywhere -no, it is permanent

What kind of fusion is being explained below? 1) Virus going inside cell using a receptor 2) Virus tells membrane that "I am going to fuse with you, I am going to combine with you and just let myself in"

1) Receptor mediated endocytosis 2) Direct fusion

What are the four steps that the viral capsid undergoes?

1) viral attachment to the host cell 2) transport the viral genome 3) packaging of the nucleic acid 4) protection of the nucleic acid

5 steps of viral rep common to all virueses?

1. attach/entry 2. translate 3. replicate 4. assembly 5. release

*Virus structure and classification* 5 things that define a virus: 1. SIZE: they are really _______. They vary greatly in size. 20nm-600nm. ______ viruses tend to cause major diseases. Giant viruses = more similar to ______ than a virus. We use electron microscopes to view viruses, but can use ______ microscopes for giant viruses. 2. SHAPE: capsid = _______ coat. They can be i______ OR h_______ and then they can either be enveloped or not enveloped. Lastly, they can be Prolate/C____ shape (bacteriophage) 3. NUCLEIC ACID: can be ss DNA or ss RNA virus, they cannot be both! 4. TYPE OF HOST: Obligate intracellular Parasite (hacks onto other things to survive) 5. Does the virus have an envelope or is it naked

1. small, small, bacteria, light 2. protein... icosahedral or helical, complex

*viral particles have 3 axes of symmetry* 1. ___ fold axis 2. ____ fold axis 3. ___ fold axis

2,3,5,

*chronic phase of hiv infection* -lasts how many years? -the virus (inc/dec) and the t helper cells (inc/dec)

2-12 virus inc t helper dec

How long did SARS-1 last?

6 weeks

Which of the following are a purpose of the viral glycoproteins which protrude from the envelope? A)Recognition of the host cell B)Alteration of the host immune response C)Filling holes left by incomplete envelope formation D)The protruding proteins do not have a purpose.

A)Recognition of the host cell

What are the two phases of noroviruses?

Acute/symptomatic and persistent

What are the two co-receptor that are important for HIV?

CD4 and CCR5

What types of cells are infected by HIV?

CD4+ cells, macrophages, dendritic cells

What are the two co receptor that can be used by HIV

CXCR and CCR5

Why are viruses considered "robot hackers"

Can't make ATP or energy for themselves cant replicate because they don't have organelles Sneak into other cells that have organelles so they can replicate Are obligate intracellular parasites(hacks other things to survive)

What are the two variations of RME?

Clathrin mediated endocytosis and Cavelion mediated endocytosis

dengue replicates on the membrane vessicles of the ____

ER

How does dengue replicate in the cell?

ER membrane Virus buds off from the ER and this is where the virus is getting its envelope from They can take their enveloped form the outer membrane of the ER (different from other viruses( Virus is going to enter the cells naturally secretory pathway, pass through the Golgi apparatus and eventually leave the cell Restricted to envelope viruses

How is the envelope made? (What structures does it go through)

ER->Golgi->PM

Which virus has a unique form of membrane fusion?

Ebola Specific mechanism of entry is unknown Fusion protein bind specially to NPC1 inside the endosome Once inside it is inside an endoscope Ebola fuse with endosome membrane Will bind to specific protein inside endosome Will allow envelope of Ebola to fuse and release of genome

T.F Host enzymes cleave the viral polyprotein into individual proteins.

False

T.F gag-pol is made in more frequently than gag

False

T/F: Viruses do not encode proteins for assembly or packaging of that genome. Capsid proteins that are responsible for making that virus shell are encoded by all the host

False Protein encoded: Assembly packaging of genome a. All viruses encode proteins for assembly or packaging of that genome i. Capsid proteins that are responsible for making that virus shell are encoded by all viruses

T/F: Proteins are responsible for complete protein synthesis machinery

False Proteins NOT encoded: Complete protein synthesis machinery 1. Some viruses can encode a part of the protein synthesis machinery but they cannot encode all of it

T/F: Viruses encode proteins that are responsible for membrane synthesis

False Proteins NOT encoded: Membrane synthesis 1. Virus don't encode proteins that are responsible for membrane synthesis 2. Specially don't encode proteins that generate lipids 3. Which is why virus gets membrane from its host

T/F: Gapped circular dsDNA can be immediately converted into messenger RNA

False a. Even though they have dsDNA, they cant be immediately converted into messenger RNA

T/F: Viruses and host cells do not share genetic information with each other

False i. Supported by genetic similarity 1. Between study of viruses and host cell (they share a lot of genetic information) a. Would make sense that they probably originated from the cells in which they share these genetic similarities

T/F: A cell must be susceptible in order to entire infectious cycle to occur

False A cell must be susceptible AND permissive in order to entire infectious cycle to occur

Which protein (receptor or fusion) is being described? i. Found of surface of viral envelope ii. Signal is sent to cause conformational change and bind to cellular surface iii. At first it has a folded confirmation, and then it it unfolded once the viral receptor has linked to the correct place iv. Fusion protein will then hairpin to pull down and open up the membrane

Fusion protein

Fusion protein exposure is _____ on pH -Leads to ______ change -PH lowers and fusion proteins ___ -And a pore eventually opens and allows for release of genome into ____

Fusion protein exposure is dependent on pH -Leads to conformational change -PH lowers and fusion proteins unfold -And a pore eventually opens and allows for release of genome into cytoplasm

The cellular origins hypothesis of viral evolution can be supported by which of the following. Check all that apply. Genetic similarity between viruses and host cells. The presence of prions. The presence of plasmid

Genetic similarity between viruses and host cells. The presence of plasmid

What is one of the last thing transcribed in retroviruses that has to be spliced mRNA?

Glycoproteins that generate envelope proteins. This is rare and has no suppression stop codon, it is spliced

cervical cancer is caused by

HPV

In a ______ cycle, once the DNA gets incorporated into the bacterial chromosome, it can sit _____ in the DNA of the bacterium until the bacterial decided to replicate. This lead to the theory of _____.

In a lysogenic cycle, once the DNA gets incorporated into the bacterial chromosome, it can sit silently in the DNA of the bacterium until the bacterial decided to replicate. This lead to the theory of evolution.

What is the difference between an infect or and disease?

Infection: virus getting into host Disease: the effects there are when a virus does get in

What viral protein takes the newly generated DNA from the cytoplasm to the nucleus?

Intergrase

How many proteins do retroviruses package?

Intergrase RT (50-100 copies PER viral particle) Protease

In a mutli-step growth cycle, cellular infection (is/is not) synchronized

Is not synchronized

Why is splicing important?

It allows for coding and expression of different messenger RNA and different proteins all from the same region of the virus

Once Pasteur demonstrated that bacteria did not need a living host to grow. ______ took the same experiement and applied them to viruses. Ivanovsky & beijerinck:

Ivanovsky & beijerinck

Which scientist wanted to figure out how tobacco plant would get disease? What experiment did they run?

Ivanovsky & beijerinck: ExperimentL take leaf mixed with fluid and filter it. Bacteria would collect at the top of the filter. Viruses would be at the bottom (with the liquid). Provided that something smaller than a bacteria would cause the disease.

What happened when influenza was discovered?

Killed millions of people, the impact a flu virus can have

*WHO* made the germ theory of disease & discovered bacteria/microorgs CAUSE disease

Koch

Who developed and applied a set of criteria for identification of the agent responsible for a specific disease( a pathogen)

Koch

A vast new world of organisms too small to be visible to the naked eye was revealed through the microscope of _______.

Leeuwenhoek

Who developed a micorscope that could see protozoa, algae, and bacteria? AND he also (disproved/proved) spontaneous generation?

Leeuwenhoek disproved

intergration(intergrase) allows HIV infection to remain for _____ of the cell

Life

What envelopes the virus in retroviruses?

Lipid membrane and matrix proteins

What does the gag protein do?

Makes several polyproteins

How does HIV enter the cell?

Membrane fusion

A segment of an integral membrane protein that spans the lipid bilayer; often a-helical

Membrane spanning domain

Which of the following is not a protein encoded by the virus? A)Replication of genome B) Assembly/packaging of genome C) Regulation of replication timing D)Viral release and spread E)Modulation of host defences F)Membrane synthesis

Membrane synthesis

What is the term that describes how viral capsid have to be strong/stable enough to protect nucleic acid but unstable enough that they can come apart when a virus enters a cell

Metastability

The ______ is the community of microorganism that reside on or with thin the anatomical sites of an organism.

Microbiome

What does VP2 do in norovirus? How many of these are encoded?

Minor stureture protein inside capsid shell Few

Rank the coronaviruses from most deadly to least

Most: MERS, SARS-1, SARS-2

Rank the coronaviruses from most transmissible to least

Most: SARS-2, SARS-1, MERS

What are the three possible outcomes to viral infection?

No apparent change Cell Death Cell transformation

Which scientist performed the famous swan-neck flask experiment which provided passive exclusion of microbes from sterilized broth

Pasteur

This scientist demonstrated that bacteria did not need a living host to grow.

Pasture

All viruses must use cellular ____ to attach to the cell and enter the cell. The purpose of these ____ on the cell is not to be a receptor for the virus. Viruses have evolved to exploit these ___ for their own purpose.

Protein

A virus that is integrated into the host genome is called a ________.

Provirus

Viral DNA that has been incorporated tred into the host genome is called a _____

Provirus

When prepping for a one/mutli-step growth cycle, why is it important o have a mono layer of cells, allow, virus to attach, and wash cells.

Purpose: all viruses in the culture are synchronized

*Alphaviruses* -enter through R___ -makes a sub____ mRNA -Genome? -Enveloped? -has a 5' ______ and a p__ _ ____

RME linear, -subgenomic enveloped - 5' cap, poly a tail

Which enzyme is used by RNA viruses to synthesize mRNA? DNA-dependent RNA polymerase Ribonuclease Reverse Transcriptase RNA-dependent RNA polymerase

RNA-dependent RNA polymerase

Which enzyme is used by RNA viruses to => mRNA?

RNA-dependent RNA polymerase (RdRp)

The gal-pol precursor has what important coding region?

RT and intergrase

For what virus was the first deliberately attenuated viral vaccine developed? Who developed it?

Rabies virus, Pasteur

Something to know about MOI is that infection depends on ____ collision of viruses with cells

Random

What is the difference between RdRp and RT?

RdRp: makes mRNA from RNA template RT: Make dsDNA from RNA template

This way of getting into the cell is the most common. It has a specific receptor which binds with the cell and then the cell will engulf it. Viruses exploit these process to enter the cell

Receptor mediated endocytosis

What two proteins are required for membrane fusion?

Receptor protein, fusion protein

This theory of evolution is described here? i. Suggests viruses were once free-living organism that lost genetic information 1. some types of bacteria are also obligate intracellular parasites that have to be inside of a cell to replicate 2. They devolved into what we know now as mitochondria

Regressive hypothesis

Replication of viral dsDNA mimics host DNA replication a. Once dsDNA gets into the nucleus it _____ can be converted to mRNA b. Virus will use ____ cellular proteins (Host RNA polymerase II) c. Once mRNA is made, it can make ____ d. Some of those proteins can be used for the formation of a ____ viral particle e. Other proteins are going to go off and impact cellular process of some sort (things that will ____ viral infection) f. Others will go on and be involved in the replication of copying of the genetic martial

Replication of viral dsDNA mimics host DNA replication a. Once dsDNA gets into the nucleus it immediately can be converted to mRNA b. Virus will use host cellular proteins (Host RNA polymerase II) c. Once mRNA is made, it can make proteins d. Some of those proteins can be used for the formation of a new viral particle e. Other proteins are going to go off and impact cellular process of some sort (things that will increase viral infection) f. Others will go on and be involved in the replication of copying of the genetic martial

(Susceptible/Resistant/Permissive) A cell does not posses a functional viral receptor. Virus cannot bind, but if nucleic acid gets inside the cell it may or may not support replication.

Resistant

What type of virus is able to incorporate its own viral genome into the human genome? What happens if it becomes incorporated into the germ line?

Retrovirus DNA gets passed down from parent to child

How did RNA viruses cause tumor if it believed that only DNA can cause these changes?

Retroviruses made DNA and incorporated itself into the host genome

Which virus uses plagues on the capsid surface?

Rhinovirus on top of plateau that the virus uses to bind

This enzyme only encoded by the virus, they need this for replication of their genetic material

RpRp

what is the most variable part of the S protein

S1

What does S1 and S2 do?

S1: globular head, receptor binding, variable (tropism) S2: more conserved, promotes fusion (mediated fusion wit endosome)

What was the first emergent coronaviruses?

SARS-CoV-1

what was the reservoir and intermediate for SARS-1 and MERS?

SARS-CoV-1: reservoir= bat, intermediate= cat MERS: reservoir= bat, intermediate=camel

What does VPg do?

Serves as a primer for viral replication Helps with initiation of translation

In one step growth cycle, all cells go through the phases of infection ________

Simultaneously

What is the primary function of the virion, an infectious virus particle?

To protect the genome

The term for the one long protein that results from the translation of the picornavirus genome is... a. a pre-cleaved protein b. a polyprotein c. none of the answer choices are correct d. a poly-cistronic message

a polyprotein

What is the coronavirus replication cycle?

a. Attachment: s-protein (S1 domain) b. Entry: clathrin- mediated endocytosis i. S2 domain fusion with endosome c. Translation of 5' end of genome d. RTC formation i. Replication translation complex e. Genome replication and formation of subgenomic mRNA f. Translation of structural proteins g. Envelope proteins embedded in ER h. Formation of ERGIC i. ER Golgi compartment 1. Bud from ER -> Golgi ii. MRNA also comes here i. Maturation of viral particle j. Cellular release

HIV is mature (before/after) the viral particle buds off

after

HIV coreceptor is

ccr5

For which virus was the first deliberately attenuated viral vaccine developed? a)Vaccina virus b)Herpes virus d)Smallpox virus d)Rabies virus

d)Rabies virus

noro targets bcells, t cells, macrophages and d___

dendritic

3rd diagnostic test of hiv

rna/dna test

Crick and Watson found most virus particles to be r____ or s_____ shaped.

rod, sphere

What protein does the immune response target to neutralize coronavirus?

s protein

What type of genome of zika virus have? is it envelope?

ss(+)RNA strand, enveloped

a virus with a helical capsid is the t______ ____ ______

tobacco mosaic virus

T/F norovirus causes little damage to host

true

Jenner worked with cowpox and Pasteur termed this ____nation

vaccination

The ____ ____ is the nucelic acid-based repository of the information needed to build, reproduce, and transmit a virus

viral genome

Our body is colonized by a community of viruses aka a v____. But it is not understood.

virome

by particle what is most abundant on earth

virus

polio and noro are unique because they don't have a 5' cap but use a ____

vpg

Complements of the (+) strand is the (__) strand

-

*+ ss RNA viruses* 1. Picornaviruses & Flavivoruses: ---bind to receptor, enter through R___ ---Genome is i________ translated by r___________ -RNA dependent RNA pol makes copies of the genome where?

-RME -Immediately -Ribosome -on membrane vesicles

What are the primary ways HIV is transmitted?

-mostly through sex -mother to child -intravenous drug abuse -blood transufions -needle sticks

*Acute phase of hiv infection* -lasts how many weeks? -infects cells in lymph nodes, what-like symptoms? -there is a counterattack

12 flu

What is the current fatality rate for covid-19?

2.2%

When are HIV structural proteins processed (before or after virus is formed)?

After virus is formed

If you test positive for the antibody/antigen test, what test should you get next?

Antibody test

what coronavirus infects fish?

Bafinivirus

Where (location) is zika highly present? Time of day?

Brazil daytime

Endocytosis -vesicle fuses with caveosome -caveosome has neutral pH

Caveolin-mediated endocytosis

An organelle that is the main microtubule-organizing center.

Centrosome

What was the first oncogenic virus discovered?

Chicken infected

The _____ microscope allowed people to see a virus particle.

Electron

Influenza Does it have an envelope? How does it enter the cell?

Envelope i. exposes a fusion peptide 1. Once inside, lower pH causes exposure of fusion peptide which fuses with endosomal membrane and allows for the viral nucleic acid to be released

T/F dsRNA genomes can be DIRECTLY translated to make viral protein

F

T/F All capsid are one of one VP/subunit

False Some viruses have one VP and others will have multiple

T/F: once you are infected with dengue a first time you shouldn't have problems if you got reinfected

False These secondary infections with dengue are the most lethal than the first

Which receptor causes problems when getting reinfected with dengue? How

Fc the virus now has the ability to bind to a second receptor, which causes an increase number of infected cells and suppress antiviral immune response

What prodrome symptoms did SARS-1 and MERS cause?

Fever chills headache malaise myalgia

T/F Copying of the genome for picornaviruses and flaviviruses occur inside membranous vesicles

Flase Occurs on the surface of membranous vesicles

what family does zika belong to?

Flavi

FLAVIVIRUSES = L_______ genome. they are e_______. makes copies on _____ _____ PICORNAVIRUSES= N___-____ genome. they are non-_________. replicates in _____

Flavi: linear, enveloped, membrane vesicles picorna: non-enveloped, non-linear, replicate in cytoplasm

Which fam of + ss rna do not have poly a tails?

Flaviviruses

What are VP made of?

Folded polypeptide chains that come together to form a structure unit. EX: polio virus has VP1, VP2 VP3

What was the first disease discovered? Who discovered it?

Foot and mouth disease Leo flyer and Frisch

How are HIV envelopes proteins generated?

From spliced mRNA

How does the HIV envelope acquire its membrane?

From the external host cellular membrane (PM)

T/F Fusion protein exposure works independent of pH

Fusion Fusion protein exposure is dependent on pH

What enSome matures the viral particle after it has budded off?

Gag-pol

What does norovirus use to cause infection?

HBGA

How many copies of RNA does HIV what? What about normal retroviruses?

HIV: 1 copy normal: 2 copies

What shape is HIV? Normal retro?

HIV: Cone shaped Normal: Icosahedral

*uncoating of the viral Nucleic Acid occurs where* at or near the site of _________ ________ ________

Nucleic Acid replication

T/F all envelopes have glycoproteins

T

T/F: In a mutli-step growth cycle, you get smaller curves compared to a single-step growth cycle but eventually both will plateau

True

What enzyme in norovirus forms the capsid structure?

VP1

zika infected hosts (can/cannot reinfect others)

can

all helical animal viruses have what

envelopes

flaviviruses AND alphaviruses are (linear/nonlinear) and (enveloped/non enveloped)

linear enveloped

viruses are O______I________ parasites

obligate intracelllular

Embedded in the membrane are viral proteins, the great majority of which are glycoproteins that carry covalently linked sugar chains, or _______.

oligosaccharides

Norovirus is an example of ss + ____

rna

how many viruses encode to MODULATEhost immune response

some

Dengue forms what in the endosome

spikes

A ______ protein is a type of integral membrane protein that spans the entirety of the cell membrane.

transmembrane

The process in which the genome is exposed is called u_______

uncoating

packaging of nucleic acids is a (favorable/unfavorable) process

unfavorable

Noro virus RDRP can either use ____ or poly ___ to initiate rep

vpg poly a tail

what was the frist human virus

yellow fever

is there a - strand intermediate?

yes

*Flavivirus: Zika* -entry: mosquito virus (A____virus) -symptoms: fever, headache, muscle/joint pain, c______, r__________ -transmission: M______, M____ to C_________, S________, Blood ________ -hosts: -is there a vaccine? -Unique: infected hosts (can/cannot) reinfect others -Cells infected by zika: Keratino_____, fibro____, D____ cells -what can it cause in babies? m_______ -where in world? B______

-Arbovirus -conjunctivis, rash -mosquito, mother to child, sex, blood transfusion -Hosts: Humans -can -NO VACCINE -Can -keratinocytes, fibroblasts, dendritic cells -microcephalitis brazil

*ss + rna* - FIRST THING THEY DO: T__________ -make individual proteins or a long polyprotein? -have a (- or +) intermediate -alpha viruses have a stop codon, so they have to make ____genomic RNA

-TRANSLATION -polyprotein - (-) -subgenomic

do ss+rna bring in any enzymes? -where do they get their rnadrp? -what do they immediately do when they enter the cell (replicate/translate into proteins) -Replication MUST come (before/after) translation

-no -host -translate proteins -after

*poliovirus* -belongs to (flavi/picorna) -has a 5' V____ and a 3' P____ ___ ___

-picorna -5' VPG -3' poly A tail

*picornaviruses* -P_______, E_______, R________ -viral genome: ___ ______ -Envelope? Replication site?

-polio, entero, rhino -non linear -non-enveloped -replicate in cytoplasm

*norovirus* -forms a p_______ -it is +ssRNA, so it is i_______ t____ -genome? -enveloped? -fam? c_______ -it has many hosts, but it is host s_____ -infects i_____ cells -leading cause of g_____ -isolated or outbreaks? -5' has a v____ (like poliovirus) -does it have a poly a tail? -UNIQUE** its RNAdrp can use either v___ or poly__ tail to start replication -transmission?

-pore -immediately translated -linear -non enveloped -calci -specific -immune -gastroentroitis -outbreaks -vpg -yes poly a tail -vpg or poly a tail -fecal oral

Hershey-Chase Experiment -determined DNA was the heritable material -labeled ________ with ratioactive S (in supernatant) -labeled _________ with radioactive P (in pellet) -Radioactive (dna/protein) was found in progeny

-protein -dna -dna

Cellular pathogenesis: Disease can result from 1) Effects of the (virus/host) replication on the host 2) effects of the (virus/host) response fighting infection

1) virus 2)host

What are the 5 steps of infection that are common to all viruses? 1)______: attach to specific cell receptor. Virus can use the same for attachment and enter or use a different receptor. Must use a receptor. Two ways to enter is Receptor-mediated _____ and membrane ______. 2)______: viral RNA-> viral protein before any further steps occur 3)_____ (copying of the genome) 4) Assemble new viruses 5)Released

1)Attachment and entry, endocytosis, fusion 2) Translation 3) Replication 4) Assemble of new viruses 5) Released

What are the three common ways non enveloped viruses interact with host cells?

1)Groves/canyons in the capsid surface 2)Plateaus on the capsid surface 3)Knobs that protrude from the virus

viruses are responsible for what percentage of cancers

20%

*Viruses are linked to Cancer* -about what percent of cancer is caused by virus? -cervical cancer = p__________ virus -Karposi's sarcoma = H_________ virus -Liver cancer = Hepatitis ___ and C

20%papilloma herpes b

*HIV turning into aids* -when there are less than ____ t helper cells -symptoms at this point: fever, fatigue, weight loss, diarrhea, hiv inc., pneumonia, fungal infections, s_______, lym__________

200 sarcomas, lymphomas

How long can norovirus last after infection? what is this called?

3 wk to 2 months persistent

viruses are between 20 and ____ nm

600

viruses make up what percentage of the human genome

8%

what percent of human genome is of viruses?

8%

A temperate bacteriophage has both lytic and lysogenic cycles. In the _____ cycle, the phage replicates and lyses the host cell. In the ______ cycle, phage DNA is incorporated into the host genome, where it is passed on to subsequent generations.

A temperate bacteriophage has both lytic and lysogenic cycles. In the lytic cycle, the phage replicates and lyses the host cell. In the lysogenic cycle, phage DNA is incorporated into the host genome, where it is passed on to subsequent generations.

If you are infected with zika, how long should you avoid mosquitoes for?

A week

Which of the following is a protein encoded by the virus?

A)Viral release and spread B)Complete protein synthesis machinery C)Energy production D) Membrane synthesis

Uncoating of the viral nucleic acid occurs... A)at or near the site of nucleic acid replication. B)just outside the nucleus. C)outside the cell. D)just after viral entry and the nucleic acid is transported to the site of replication,

A)at or near the site of nucleic

One of the functions of the viral capsid is to.... A)attach to host cells. B)dampen host immune responses. C)arrange itself in the proper shape. D)grow as large as possible.

A)attach to host cells.

what does the spike protein bind to?

ACE2

*Viruses cause life threatening illnesses* -AIDS (H___) -In________ R_______ S_______ E______-

AIDS, HIV Influenza Rabies Sars Ebola

These are proteins encoded by (all/some/none) viruses 1. rep of genome 2. assembly package 3. amplify immune response

ALL

how many viruses encode to assemble/package the genome

ALL

What therapy is currently being used right now to treat HIV?

ART

What are some of the differences between acute and chronic phases of infection

Acute: R5 strain binds to CCR5. Gets into macrophages and T cells. Flu like symptoms. Immune system can still control. Will last 12 weeks Chronic: immune system is TRYING to control infection. Usually last 2 to 10 years. Virus increases and T cells decreases

When does the viral particle mature (before or after budding)?

After budding

Viral receptors on the cell surface.... A)All of the choices are correct B)Can bind directly to icosahedral virus capsid proteins C)Interact with glycoproteins of enveloped viruses D)Can be carbohydrate or protein molecules E)Have cellular functions

All

what are the three genera of coronaviruses

Alpha-human coronavirus (most common cause of cold 50%) Beta-SARS-CoV (SARS-CoV-1, MERS, SARS-Cov-2) Gamma ( avian, infects birds)

What happens in a one-step growth cycle chart at the end?

Amount of virus levels off eventually because there is no more live cells to infect and replicate

What kind of drift is being described here? i. Influenza viruses 1. Have 8 segments 2. With very replication there will be small changes in the nucleic acid 3. If these proteins change that means that the antibodies in my body won't recognize this new mutation that well

Antigenic shift

What kind of drift is being described here? i. More dramatic change ii. Two different strains infecting the same cell 1. Human and pig influenza affecting same cell 2. Union packing you can get mix of viral genome in one new viral genome iii. Cause widespread disease, cause large pandemic

Antigenic shift

Which type of viral evolution results in large changes to the viral genome? Lytic evolution Antigenic shift Progressive evolution Antigenic drift

Antigenic shift

At an MOI=1, which of the following statements is correct? a)there will be no eclipse period in the growth curve b)on average, approximately 1 virus was added per 1 target cell c) all of the choices are correct d)only 1% of the cells in the culture will be infected

B

Why is the microbiome beneficial to us?

Bacterial community that help our intestinal track(responsible for digesting our food) and helps out our immune system

Once the ______ was discovered, scientist realized that viruses can infect bacteria aka one microorganism can infect another

Bacteriophage

What are some ways that a virus can move from one individual to another (horizontal)?

Bloody secretions snot,fluids Feces (noravirus) Genitalia (HIV) Blood(HIV, rubella)

How many strand/s of viral DNA does RT make? What will happen to these strand/s?

Both strands will be integrated into the host cell

Why do most RNA containing viruses replicate in the cytoplasm? A)Because they don't possess the transport mechanisms to migrate to the nucleus. B)Because RNA can't get into the nucleus C)Because all of the cellular replication machinery they need is located cytoplasm D)None of the answer choices are correct.

C)Because all of the cellular replication machinery they need is located cytoplasm

ALL virons contain at least 1 protein coat (the c_____ or nucleocapsid that protects the NA genome)

CAPSID

What receptor triggers the extension of the fusion protein?

CCR5

What is the primary receptor for HIV?

CD4

Cells have no RNA-dependent RNA polymerases that can replicate the genomes of RNA viruses or make mRNA from RNA templates. One solution to this problem is that RNA virus genomes encode _______ RNA from RNA templates. The other solution, exemplified by retrovirus genomes, is ______ of the genome to dsDNA, which can be transcribed by host RNA polymerase.

Cells have no RNA-dependent RNA polymerases that can replicate the genomes of RNA viruses or make mRNA from RNA templates. One solution to this problem is that RNA virus genomes encode RNA-dependent RNA polymerases that produce RNA from RNA templates. The other solution, exemplified by retrovirus genomes, is reverse transcription of the genome to dsDNA, which can be transcribed by host RNA polymerase.

This theory of evolution is described here? i. Cells came first and then viruses ii. Viruses are deprived from bits of nucleic acids that somehow "escaped" 1. Slipped out of cellular homes from the cellular organism they were housed in 2. Nucleic acid are free and stayed intact and from there you get viruses that evolved 3. Plasmid a. Circular DNA found in prokaryotes 4. Explains why viruses are so specific a. because they come directly form the cells that they possibly are going to infect

Cellular Origin hypothesis (progressive hypothesis )

Viruses moving within the cell is an active process. Adenovirus subviral particles are loaded onto microtubules through interaction of the capsid protein, hexon, with dynein. The particles move towards the _____ and are then released and dock onto the nuclear pore complex, prior to viral genome entry into the nucleus.

Centrosome

Endocytosis -forms endosomes -endosomes acidifies -endosomes eventually fuse with lysosomes

Clathrin-mediated endocytosis

This theory of evolution is described here? i. Starting cells and viruses may have evolved together ii. Viruses defiantly must have appeared early in the history of life, before the 3 domains that cells diverge 1. Bacteria, vs arches vs eukaryotes

Co evolution hypothesis

What is the first step of retroviral intergration? What enzyme does it use?

Conversion of viral RNA into DNA using RT

What viruses are transmitted through mosquitoes?

Dengue fever, chikungunya fever

Which of the following does not play a role in virus entry and movement through a cell? A)Diffusion of virus particles in the cytoplasm B)Clathrin-mediated endocytosis C)Fusion of viral and plasma membranes D)Microtubule-mediated transport

Diffusion of virus particles in the cytoplasm

Dengue Does it have an envelope? How does it enter the cell?

Envelope i. -form spike-like structures 1. Fuse with endososmal membrane

What do envelope viruses use to attach to cells?

Envelope viruses attach to cells using producing viral glycoproteins

What are two types of alphaviruses?

Equine encephalitis Chikungunya

______ lead has lead to the formation of only seven major times of viral genome

Evolution

T.F retroviral ss+RNA genomes are immediately translated

False

T/F The structural subunits of viral capsids have identical bonding contacts

False

T/F A resistant cell has a viral receptor but will not support viral replication.

False

T/F Carbohydrates and proteins cannot be a cellular receptor

False

T/F Entry and movement through a cell is a passive event

False

T/F Once in the lysogenic cycle, bacteriophage can never switch back to the lytic cycle.

False

T/F Only a few enveloped viruses have viral proteins protruding from the envelope.

False

T/F The ability of viruses to grow and replicate outside of their host cells is a characteristic that makes them highly infectious and is important for transmission.

False

T/F The initial adherence of viruses to host cells are guided by electrostatic forces and are extremely specific.

False

T/F coronaviruses is one of the smallest of all ss(+) rna viruses

False

T/F once you get infected with norovirus you will have long lasting immunity

False

T/F: Endocytosis cannot occur without clathrin or cavelin

False

T/F: Influenza virus was discovered before the first oncogenic virus was discovered.

False

T/F Direct fusion does not have to use a receptor to enter the cell

False Both Receptor mediated endocytosis and Direct fusion use a receptor to enter the cell

T/F: For dengue fever, a high pH induces a variety of endosome escape mechanism (conformational change)

False Low pH

T/F: Viruses do not encode for proteins that are needed for releasing and spreading of those viruses after they've gone through the cycle of replication

False Protein encoded: Viral release and spread a. Genes responsible for releasing and spreading of those viruses after they've gone through the cycle of replication

T/F The goal of a virus is to cause death

False Viruses require a live host so they don't want to kill the cell. Most viruses (rhino viruses) don't cause death. If it does cause death it usually takes years (HIV)

T/F: You have to make subgenomic RNA after you make capsid and envelope proteins

False You have to make subgenomic RNA first and then you can make capsid and the velopme proteins

T/F: Yellow fever, west nile, zika are all dead end host

False Zika isnt

T/F: viruses can only use RME or membrane fusion

False can use both

T.F: there are moderate titers of virus shed in feces during the acute phase of norovirus

False high titer

T/F Envelope viruses interact with host cell receptors by using viral glycoproteins that are non-specific

False it is very specific

T/F Subgenomic mRNA encodes for viral nonstructural proteins

False structural proteins

T/F Noroviruses discriminates against young, old and immunocompromised

False It will infect anyone

T/F: In a one-step growth cycle not all cells have to be infected at the same time

False, all cells must be infected at the same time. If they are not then you get a Mutli-step growth cycle.

T/F The triangulation # is determined from th 3-fold axis of symmetry

False, it is the 5-fold

T.F HIV can only infect T cells

False, it primary infects T cells but it can infect other cell times too like macrophages and dendritic cells

What are the three shapes a capsid has?

Helical, icosahedral, complex

Who was the scientist response for finding out that DNA was a heritable genetic material? How did he do this?

Hershey Chase Used bacteriophages. Track radioactivity and saw that DNA is passed on from parent to offspring

Who designed an experiment that solved the question, What is the genetic material of the phage? Is it the material of the phage? DNA? Protein?

Hershey and Chase DNA is the genetic material

A ____(low/high) MOI must be used to generate a single one-step growth curve. A ____(low/high) MOI must be generate a mutli-step growth curve

High(5-10), low(0.1)

What are the three ways viruses can be transmitted from host to host?

Horizontal transmission (most common) Vertical transmission Zoonotic transmission

What does HIV use to replicate its genome (host or viral polymerase)?

Host polymerase

How is norovirus transmitted? Is it stable? Is it infectious? where does it usually spread?

How is norovirus transmitted? fecal-oral Is it stable? yes, can survive wks to months in water or oil Is it infectious? yes where does it usually spread? nursing homes, cruise ships

ssDNA a. First step: ssDNA has to be converted to _____ before it can be replicated and converted into messenger RNA (This uses cellular host ____ to do this process) b. Replication then happens the same way dsDNA replicates c. DNA ____ is used for copying the DNA genetic material (Get both negative and positive strand and either one of these can be incorporated into the new viral particle)

I a. First step: ssDNA has to be converted to dsDNA before it can be replicated and converted into messenger RNA(This uses cellular host proteins to do this process) b. Replication then happens the same way dsDNA replicates c. DNA polymerase is used for copying the DNA genetic material (Get both negative and positive strand and either one of these can be incorporated into the new viral particle_

*WHO* did tobacco mosaic disease & discovered something SMALLER than bacteria cause disease

I and B

Who associated microorganisms with disease? He created ______'s postulate (a set of criteria to identify an agent responsible for a disease) 1. org. REGULAR ASSOCIATION with disease 2. org. ISOLATION from diseased host & grown in culture 3. disease REPRODUCED when org is introduced to new host 4. same org must be REISOLATED from experimentally infected host

Koch

Who developed this criteria for identifying a pathogen? The bacteria must be present in every case of the disease. The bacteria must be isolated from the host with the disease and grown in pure culture. The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.

Koch Postulates

What portion of the new viral DNA has to get cut in half for it to be intergrated inot the host genome? Why?

LTR, catalyze the cleavage of DNA. Once cleavage happens then intergrase can bind viral and host DNA

What is a mechanism that uses the grooves and canyons in the capsid surface? Provide an example of a virus that does this

Lock and key type mechanism Poliovirus, has a five fold axis with protruding and grooves

What does the eclipse period look like for a one-step growth cycle? Why?

Low and doesn't grow, looks like there is little virus. Virus is in the cell and is replicating so it does not seem like there is INFECTIOUS virus outside.

What areas of the body does HIV enter and replicate

Lymph node, infects everything from there

Before generating a growth cycle you need to know the _____. (Number of viruses and number of cells that you are going to be infecting)

MOI

What is your MOI if you add 1000 viruses to 100 cells?

MOI of 10

This can be used by some very small viruses. They use it to sample extra cellular outside and for getting into cell

Macropinotosis

How do you prevent zika?

No vaccine precautions when traveling to areas with high mosquitoes bug spray all day long sleeve

What kind of bond do VP have?

Non covalent

The initial adherence of a virus to a cell is ______ and is guided by ______ forces. It is not a hard binding.

Nonspecific, electrostatic

What enzymes does norovirus encode for first?

Nonstructural proteins like RDRP, and protease

_____viruses are an example of viral +ssRNA, which can be directly ____. They have the most _____replication strategy. Although it does need ____, it does not package it into its capsid.

Noraviruses are an example of viral +ssRNA, which can be directly translated. They have the most efficient replication strategy. Although it does need RdRp, it does not package it into its capsid.

Which of the following viruses forms a pore in the endosomal membrane in order to release its nucleic acid into the cytoplasm? Check all that apply. Influenza Virus Norovirus Adenovirus Dengue Virus Poliovirus

Norovirus and polio

What is the multiplicity of infection (MOI)?

Number of viruses added per cell

What kind of parasites is a virus? Explain.

Obligate intracellular parasites Cant grow in an inanimate object, can only grow in a host

(Susceptible/Resistant/Permissive) A cell can replicate the virus. This does not guarantee that the virus has the receptor

Permissive

What is the difference between phagocytosis and endocytosis ?

Phago is done by immune cells and takes up large molecules Endo takes yo small particles and can be used for cell entry

____ assay can only quantify infection whole virus particles when preforming one/mutli-step growth cycle.

Plaque

The gag-pol complex is translated into a _____

Polyprotein

What does virus in latin mean?

Posion

______ of viruses is dependent on essentially random encounters with potential host and host cells. Viral ____ is critically depending on the production of large number of progeny virus particles which surfaces composed of many copies of structures that enable the attachment of virus particles to susceptible cells.

Propagation

The gag-pol complex is processed by the packaged viral ______

Protease

Retroviruses packages its own ____. Once it gets converted to ssDNA it used _____ enzymes to convert that into dsDNA. The DNA then goes into the nucleus and gets integrated into the host _____ (unique). Once this integration happens it is called a ____.

Retroviruses packages its own RT. Once it gets converted to ssDNA it used cellular enzymes to convert that into dsDNA. The DNA then goes into the nucleus and gets integrated into the host chromosomes (unique). Once this integration happens it is called a provirus.

Gapped circular DNA uses _______ to convert RNA to DNA. ______ is not an enzyme that is encoded by any host proteins, this is strictly a virtually-encoded enzyme.

Reverse transcriptase

What are the five things that define a virus?

Size, shape, envelope, Nucleic acid, type of host

How can pol continue to read the mRNA if there is a stop codon next to gag?

Stop codon can be skipped about 10% of the time

(Susceptible/Resistant/Permissive) A cell possesses the functional receptor for a virus. Virus can bind, possibly enter, but replication os not guaranteed

Susceptible

What determines the capsid shape?

Symmetrical order of viral proteins

When do symptoms occur in norovirus? what are they? what are the treatments? prevention?

Symptoms being within 24 hours of ingestion (Diarrhea, Nausea, Vomiting, Headache (dehydration) Self limiting infections; resolves within 18 to 48 hours Treatment (Oral rehydration, No drugs available Prevention( No license vaccine)

For zika, what are the: Symptoms: Incubation: Treatment: Spread:

Symptoms: mild fever and rash Incubation: few days to weeks Treatment: rest, water, acetaminophen Spread: transmitted mother to baby, mosquitoes, sexual contact

T/F + ss RNA genomes may be DIRECTLY translated to make viral protein

T

T/F There are some viruses that only encode 1 viral protein

T

T/F both lytic and lysogenic rep cycles integrate into host

T

What are the three encoding proteins that makes HIV genome more complex?

TAT, NEF, REV

The cellular origin hypothesis is also called the ______ hypothesis. This theory is based on the idea that these mobile genetic elements or _____, progressed overtime to gain the ability to exit and enter cells on their own

The cellular origin hypothesis is also called the progressive hypothesis. This theory is based on the idea that these mobile genetic elements or plasmids, progressed over time to gain the ability to exit and enter cells on their own

Which of the following steps is found in Dengue virus replication but not Poliovirus replication? a. The viral RNA forms a circle prior to joining with the replication complex b. The production of a (-) sense RNA intermediate c. Cleavage of viral proteins by a viral protease d. The production of (-) sense RNA using and RNA-dependent RNA polymerase (RdRp)

The viral RNA forms a circle prior to joining with the replication complex

There are no known host cell enzymes that can copy the genomes of RNA viruses. However, at least one enzyme, ________ , can copy an RNA template.

There are no known host cell enzymes that can copy the genomes of RNA viruses. However, at least one enzyme, RNA polymerase II, can copy an RNA template.

Which two viruses are an example of helical?

Tobacco mosaic virus and vesicular stomatitis virus

Which coronaviruses infect cattle and possibly humans? What disease does it cause? Why is this important

Torovirus Gastrointestinal (enteric disease) we can see how covid-19 also infects our gut by comparing it

What are the envelope glycoproteins?

Trans membrane and surface

Replication of viral dsDNA mimics host DNA replication ______ and ____ of the proteins must happen first because all copying of genetic material uses some sort of viral protein

Transcription, translation

What does TAT, NED and REV do?

Transport splice RNA out of nucelus, dampens the host immune response, helps with HIV pathogenesis

T.F Tumor formations result from permanent changes to the cell.

True

T.F after intergration, HIV relies solely on host proteins to replicate

True

T.F capsid remains intranet when converting RNA to DNA

True

T.F during viral intergration into host genome, host DNA gets duplicatied. This is permanent

True

T.F matrix and capsid proteins drive retrovirus budding from the cell

True

T.F most of the enzymes and proteins that the virus uses to replicate belong to the host cell

True

T.F once viral DNA gets incorporated into host genome it is permanent. This can happen anywhere

True

T.F processing of gag-pol occurs inside of the viral particle after budding

True

T.F s protein is important for binding and entry into the host cell

True

T.F: there are moderate titers of virus shed in feces during the persistent phase of norovirus

True

T/F ADE occurs when someone is infected with new dengue strain

True

T/F Nucleocapsid is a substructure and the capsid is naked

True

T/F Viral pathogenesis requires both infection and disease

True

T/F Young, old and immunocompromised are susceptible to death with norovirus

True

T/F a virus can have a single or multiple receptor proteins

True

T/F coronaviruses infect a wide range

True

T/F in a mutli-step growth cycle, only a small amount of cells are actually infected at first

True

T/F non enveloped RNA viruses utilize the low pH of the endosome to degrade the capsid

True

T/F noro is described as the perfect pathogen

True

T/F noroviruses have unique cellular tropism

True

T/F the envelope is always a lipid bilayer

True

T/F the more subunits, the larger the capsid

True

T/F" The lowering of internal pH is a major difference between endosomes and caveosomes.

True

T/F: (-)ssRNA viruses must package their own RdRp

True

T/F: A. The coevolution hypothesis assumes viruses came first

True

T/F: Ebola and SARS are examples of zoonotic infection

True

T/F: Edward Jenner, recognized the principle on which modern methods of viral immunization are based.

True

T/F: Gapped circular dsDNA uses the mRNA that was made using host transcriptional factors to copy its genome ( not the original one it came with)

True

T/F: If you dont have any HBGA then you are highly resistant to noro

True

T/F: Not all (+) RNA is mRNA

True

T/F: One step growth curve analysis can provide quantitative information about different virus-host systems

True

T/F: Picornaviruses and flaviviruses enter through RME

True

T/F: SARS-Cov-2 is more transmissible but less deadly

True

T/F: Some viruses use the same receptor for attachment and entry. Some viruses have separate receptors for attachment and separate for entry.

True

T/F: in a mutli-step growth cycle, its eclipse is much shorter then a one-step growth cycle

True

T/F: the initial adherence of a virus to a cell is a random event which helps if you have a lot of viruses

True

T/F: viruses are obligate intracellular parasites, the genome must enter a cell for the viral reproduction cycle to occur.

True

T:F/ Viruses benefit us by priming our immune system

True

T.F: Gapped circular dsDNA has a portion that is dsDNA and portion that is ssDNA and also have an RNA molecule woven in there

True First, the single portion of DNA needs to be repaired and converted into ds DNA i. This virus uses the host cellular enzymes to repair its genome ii. Once the genome is repaired, it can then go through the normal process of transcription and translation

T/F: Viruses have proteins that are responsible for regulating replication

True Protein encoded: Regulation of replication timing i. Herpes that can go latent inside of a cell ii. The genes that are responsible for latency cant be turned on as soon as the virus infects iii. The timing and expression of those genes is very important to whether or not the virus is causing an acute infection or whether the virus or causing a latent infection

T/F: All of the energy that a virus gets, it gets from a host cell

True Proteins NOT encoded: Energy production 1. Viruses don't produce enzymes can that generate ATP

T/F: Viruses can survive on an intimate surface and continues to be infectious and spread

True However it cannot grow and replicate

T/F: Viruses are responsible for encoding proteins that will modulate host defenses

True Protein encoded: Modulation of host defenses i. All viruses have proteins on their surface which 1. amplify the immune response 2. Cause the generation of antibodies 3. Recruitment of cytokines and T cells ii. Some viruses encode for proteins that dampen the immune response 1. Allow them to go into latency or hide from the immune system so they can cause more widespread disease

T/F: Every virus must encode some sort of its own genome replication machinery

True Protein encoded: Replication of genome

T/F The envelope always comes from host cell

True virus membrane is always host derived

non evenloped viruses being taken up by RME uses micro ____ to move the nucleic acid to the proper stop of replication

Tumbles

Retroviral integration results in ____ characteristic features

Two

*ss + rna* -how are ss + rna similar to mRNA? 5' and 3' U____, 3' P____ ___ ___, and protein on the ___ end

UTR poly a tail 5'

Does translation of the gag and pol protein happen with unspliced or spliced retrovirus? What about translation of envelope protein?

Unspliced: translation of the gag and pol proteins spliced: translation of envelope protein

What enzymes does the second open reading frame of norovirus encode for?

VP1, VP2, VPg, polyA tail

Virus receptor interactions are highly ______. Very different viruses can bind to the same receptor. Viruses of the same family can bind to different receptors.

Variable

_______ was the method of inoculation first used to immunize individuals against smallpox (Variola) with material taken from a patient or a recently _____ individual, in the hope that a mild, but protective, infection would result.

Variolation, variolated

Virus Transmission from mother to child

Vertical transmission

The process by which viruses cause disease is called _______

Viral pathogenesis

Capsid are made from viral structural proteins. Structure proteins are designed as VP (____ _____) or also called _____

Viral proteins, subunits

What does the burst/yield period look like for a one-step growth cycle? Why?

Virus increases exponentially. High grow of infected cells, cells burst, Viruses are. Being released from cell.

Cell death can be ____ induced(ex cell lysis, apoptosis) or ____ induced (result of the innate immune response and then adaptive immune response)

Virus, host

Why is viral attachment to host cells a two step process?

Viruses don't have any means of locomotion so there is the initial adherence and then the viral attachment which is mediated by binding of host receptor

How did Edward Jenner develop the modern vaccine? Who else developed it before him?

Women who worked with cows & got cowpox were immune from smallpox. Took scrapings of cowpox and put it on people. -Lady montague brought this process to england from china -variolation: took scrapings... blew into face of uninfected individual(CHINA)

What was the first human virus discovered? How was it transmitted?

Yellow fever (Transmitted bu mosquitoes to humans)

Does coronavirus have an envelope?

Yes

What happens if someone has CCR5 under expressed or expressive at low levels?

You can be resistant to HIV infection

What happens if you have a homozygous/heterozygous mutation to your CRCX4 or CCR5 cells?

You will have resistance/immunity

A cross-species infection is also known as a z_______ infection. Examples include: A____ and S____

Zoonotic - any infectious disease that may be transmitted from other animals, both wild and domestic, to humans or from humans to animals. AIDS, SARS

Which of the following are true of viral infection? a)The receptors molecules on the surface of the cell determine which type of cells the virus can infect b) Infected cells behave and function normally when infected by a virus c)Most viruses don't actually get inside cells but instead just inject their DNA d)Viruses only infect humans and animals but not other living things

a)The receptors molecules on the surface of the cell determine which type of cells the virus can infect

Identify which group(viral genome) is being described: i. The viral DNA gets converted into RNA ii. Goes through the process of RT to make ds DNA, which then can be converted into messenger RNA

a. (+/-)ds/ssDNA

Hoe does (-)ssRNA work?

a. RdRp is what is used for the conversion of the viral genome into messenger RNA, which will then get translated into proteins, and those can get used for the formation of the viral capsid or for copying of the genetic material b. They make more of the RdRp which not only copies from the (-)RNA to make (+)RNA, but it is also used in the conversion of that (+) into (-) strand c. -RNA is what

How are the nonstructural proteins processed? structural proteins?

a. Replication and transcription complex (RTC) i. 15-16 genes encodes in OTF1a-ORF1b ii. Non structural proteins b. Structural and accessory proteins translated from subgenomic mRNA

For ss (+) RNA viruses, which protein is responsible for copying the genome? a. The RNA-dependent RNA polymerase (RdRp) b. The Reverse Transcriptase c. DNA-dependent DNA polymerase d. The ribosome

a. The RNA-dependent RNA polymerase (RdRp)

What cells are infected during acute infection of noroviruses? epithelial?

acute: immune cells like t cells, dendritic cells, macrophages epithelial: epithelial cells

Protease packages the poly protein (before/after) budding

after

how many viruses encode for replication of genome

all

how many viruses encode to amplify immune reponse

all

following the antibody/antigen test, doctors will use

antibody test

*Diagnosis of HIV* -Best test: antibody/a_____ test -followd by: a________ test -also there is a rna/dna test

antibody/antigen antibody

best diagnosis test of hiv

antibody/antigen test

A antigenic (shift/drift) results in a LARGE change to the viral genome

antigenic shift

How is Zika transmitted?

arbovirus = transmitted through arthropods (mosquitoes)

An important function of the viral capsid is to a______ to host cells

attach

The first deliberately _____ viral vaccine was made by Louis Pasteur. After several passages, the resulting preparations caused mild disease (i.e. were _____) yet produced effective immunity against rabies.

attenuated

What are the complications with zika

baby born with microcephaly ( small head and brain)

by biomass what is most abundant on earth

bacteria

the complex capsid shape (prolate) belongs to b________ and re____

bacteriophage and reo

*History* 1. Leeuwenhoek: first to visualize microscopic orgs 2. Pasteur: bacteria are present/functional 3. Koch: microorgs are responsible for disease. Germ theory of disease 4. Ivanovsky & beijerinck: tobacco mosaic disease. something smaller than bacteria could cause disease! 5. Leoffler & Frosch: discovered first animal virus... foot and mouth disease 6. first human virus discovered 7. first oncogenic (cancer-causing) virus discovered 8. bacteriophage discovered... viruses can infect bacteria (one microorg can infect another) 9. electron microscope 10: influenza discovered 11. hershey-chase: proved that DNA was the heritable genetic bacteria (used b__________)

bacteriophages

Viral diseases impacted humanity long (after/before) they were understood. *know ancienct texts * dont know dates *know order in which things happened * know names & what they did * know details of experiement

before

Antigenic Shift is a (big/small) change

big

The yield from one cell is one iral generation; it was called the ____ because viruses literally ____ from the infected cell.

burst

Which of the following is an example of horizontal transmission? a) acquiring a viral infection during childbirth b) acquiring a viral infection by being bitten by a mosquito c) acquiring a viral infection from touching a contaminated door knob d)acquiring a viral infection after being bitten by a dog

c) acquiring a viral infection from touching a contaminated door knob

Prolate is a viral shape variant found in a)Mammalian viruses. b)Human viruses. c)Bacteriophages. d)Retroviruses. e) Plant viruses.

c)Bacteriophages.

What contributes to the cyclical nature of Norovirus outbreaks? a. Loss of herd immunity b. None of the answers are correct c. Viral evolution and the emergence of new viral strains d. Changes in seasons

c. Viral evolution and the emergence of new viral strains

Which of the following statements is TRUE. a. flaviviruses generate individual mRNAs for translation b.cellular enzymes are responsible for cleaving the polyproteins of Flaviviruses c.viral enzymes are responsible for cleaving the polyproteins of Flaviviruses

c.viral enzymes are responsible for cleaving the polyproteins of Flaviviruses

Norovirus is non-envloped and is in the c_____ fam

calci

First retroviruses discovered were c______

cancerous

*entry and movement through a cell is an ACTIVE event* -viruses (can/cannot) diffuse through other cellular membranes or through the cell once it enters

cannot

Regardless of their structural complexity, all virions contain at least one protein coat, the _____ or nucleocapsid which encases and protects the nucleic acid genome

capsid

what is a protein coat that can be icosahedral, helical, or prolate (bacteriophage) shape?

capsid

what structure aids in attachment, transporting the viral genome, packaging the nucleic acid, and protecting the nucleic acid

capsid

HIV primary receptor is

cd4

macrophages, t helper cells, and dendritic cells all have ___ receptors

cd4

*co receptors needed for hiv infection *

cdc4, ccr5

Which evolution hypothesis states that cells came first, viruses came second (cellular origin/coevolution)

cellular origin

what was the first oncogenic virus

chicken leukemia

*viral genomes vary widely in size* -____________________= smallest virus

circovirus

hepatitis are what shape of viral genome

circular gapped

Dengue fever receptors ___: used for normal virus replication ____: used for antibody-dependent enhancement

cognate Fc

dengue is flavi (enveloped) and has 2 receptors which are?

cognate, fc

bacteriophage and reovirus have a c___________ capsid shape

complex

the shape of HIV's nucleocapsid is a ______ shape. other retroviruses have one in the __________ shape

cone icosahedral

Binding of CD4 induces a _____ change int he viral envelope protein (fusion protein) to allow interaction with CCR5

conformational

Vaccina (vaccine) is derived from the word vacca, which means ___

cow

Noroviruses outbreaks occur in a ____ fashion. Usually in ____

cyclical, January

Which of the following statements are true of all viruses? a) They all possess the same type of nucleic acid b)All of the answers are correct c)They are all enveloped d)They all have a protein capsid that encases their genetic material

d)They all have a protein capsid that encases their genetic material

What causes death in norovirus?where does it occur?

dehydration developing countries

which flavivirus replicates on membrane vessicles of the ER?

dengue

*Which does NOT play a role in virus entry/movement thru a cell?* -mircorubule-mediated transport -fusion of viral and plasma membranes -diffusion of virus particles in cytoplasm -clathrin-mediated endocytosis

diffusion of virus particles in the cytoplasm

Viruses use cellular proteins to enter cell. Viruses have evolved to take advantage of cell receptors. Envelopes give viruses the option of endocytosis OR fusion aka _______ fusion

direct

*Virus benefits* 1. Major biological discoveries: proved that ____ is the genetic material. 2. New techniques: reverse __________ (Viruses encore this specific enzyme and it has lead to our understanding of how genes function), genome ________(retroviruses and understanding how they edit the host genome) 3. Curing disease: gene ________(curing disease), oncolytic viral ______ (cancer killing viruses) PRIME IMMUNE RESPONSE

dna transcription editing therapy therapy

retroviruses, like hiv, (do/do not) immediately translate

do not

small changes is antigenic _____

drift

Identify which group(viral genome) is being described: use host enzymes to convert its double-stranded DNA into messenger RNA using the cellular process of transcription

dsDNA

Which DNA genome, on entry into the cell, can be immediately copied into mRNA?

dsDNA

Which DNA genome, upon entry into the cell, can be immediately copied into mRNA? Linear ssDNA all types of DNA can be immediately copied to mRNA Circular ssDNA Gapped dsDNA dsDNA

dsDNA

ssDNA(can be - or +) must become ______ before it can be replicated in the cell

dsDNA

What are the three groups in the Baltimore system that can be immediately converted into mRNA using either host or cellular enzymes

dsDNA, ssRNA, (-)ssRNA, (+)ssRNA

dsRNA viruses must package an _____ Can be made up of (-/+) RNA needs to be converted into mRNA, in order to do that they need ____ , which comes from inside the viral particle. Package genetic material and ____

dsRNA viruses must package an RdRp Can be made up of both -/+ RNA needs to be converted into mRNA, in order to do that they need RdRp, which comes from inside the viral particle. Package genetic material and RdRP

Identify which groups(viral genome) are being described: genomes use viral enzymes that are packaged within the virus and come in with the virus to immediately convert their type of genome into messenger RNA

dsRNA, (-)ssRNA

The results of this experiment (one-step and multi-step) defined two new terms in virology: the ____ period, the phase in which infectivity is lost when virions are disassembled after penetrating cells; and the _____ period, the time it takes to replicate, assemble, and release a new virus particle before lysis.

eclipse, latent

viruses are very small and can be seen with what microscope

electron microscope

a nucleocapsid is just a capsid in an

envelope

some viruses have an ___________, derived from host cellular membranes.

envelope

Rhandoviruses Does it have an envelope? How does it enter the cell?

envelope i. envelope proteins change conformation 1. Fusion with endosomal membrane occurs early after entry 2. PH hasn't yet changed much and is often just below neutral at pH right around 6 3. When it reaches this pH the viral envelope begins changing and allows the fusion protein to be exposed 4. Once protein is exposed it fuses with the endosome and ultimately releases the viral nucleocapsid into the cytoplasm

flavi viruses are (non-enveloped/enveloped)

enveloped

retroviruses like hiv are (enveloped/non enveloped)

enveloped

*retroviruses* -are they enveloped? -lipid bilayer, matrix proteins, nucleocapsid -3 distinct proteins: i___, p___, r___ ____ -UNIQUE: how many copies of the ss+RNA do retroviruses have? -instead of generating 1 polyprotein like other +ssRNA, retroviruses generate__________ -protein order: g___, g____-___, e____

enveloped -integrase, protease, reverse transcriptase - 2 copies -several - gag, gag-pol, env

All _____ have viral glycoproteins protruding out ways. This is necessary for recognition of the host cell and to fuse with host cell (important for viral replication)

envelopes

In an icosahedral, all subunits interact with their neighbors in an identical (or ____ ) manner, just like the subunits of helical particles such as that of tobacco mosaic virus.

equivalent

dengue gets its envelope from the

er

By particle number, viruses _______any life form But by biomass, (bacteria/viruses) are #1

exceed bacteria

*WHO*for I and B (tobacco mosaic disease) where was the disease causing agent? (filtered liquid/bacteria solid on top)

filtered liquid

tobacco mosaic virus, the f_______ virus to be identified. (+ SS RNA)

first

Yellow fever, west nile, zika, dengue all belong to what fam

flavi

Yellow fever, west nile, zika, dengue are (flavivirus/picornavirus)

flavivirus

Calicivirus Does it have an envelope? How does it enter the cell?

form a pore in the endosomal membrane 1. Spike penetrates

retroviruses like HIV enter thru ______-

fusion

The precise mechanism by which lipid bilayers fuse is not completely understood, but the action of fusion proteins is thought to result in the formation of an opening called a ____ ____ , allowing exchange of material across the membranes

fusion pore

*membrane fusion is regulated by 2 sets of proteins* -successful viruses keep the protein folded -fusion protein + receptor protein -fusion protein undergo conformation change, then go into _____________ structure where membranes fuse

hairpin

tobacco mosaic viruses and rabies viruses have what capsid shape

helical

liver cancer is caused by

hep b and hep c

*gapped dna* -viral family: h____dnav_____ -starts as partially ds... has to be repaired before it is made into mRNA

hepadnaviridae

hershey and chase found that dna was

heritable

karposis cancer is caused by

herpes

HIV uses (its host/its own) proteins to replicate

host

envelopes always come from the h___

host

who does the envelope always come from

host

Viruses cannot grow without being inside a _____ cell. But they can survive without a ____ cell (wiping down surfaces)

host host

The receptor may determine the ____ _____ of a virus, i.e., its ability to infect a particular animal or cell culture

host range

what does coronavirus infect?

humans, domestic animals, avian species

What proteins does coronavirus have on the envelope? function?

i. S-glycoproteins ii. HE-glycoproteins: hemagglutinin-esterase (not essential; not all coronaviruses have it) iii. M-glycoproteins 1. Important for viral assembly iv. E-glycoproteins ( present in small amounts) 1. Important for viral assembly

the structure of HIV nucleocapsid is a cone other retrovirus nucleocapsids are ________

icosahedral

*icosahedral structure* - 20 triangles (faces) & 12 verticies (2,3 and 5 fold), 60 I______ subunits = minimum # needed for icosahedral

identical

Viron is an i_________ virus particle & it p______the genome.

infectious protects

Viral glycoproteins are ______ proteins firmly embedded in the lipid bilayer by a short membrane-spanning domain

integral membrane

_____ proteins include transporters, linkers, channels, receptors, enzymes, structural membrane-anchoring domains, proteins involved in accumulation and transduction of energy, and proteins responsible for cell adhesion.

integral membrane

What is the function of the polyA tail?

involved in genome replication

*WHO* is credited with development of vaccines

jenner

zika targets k_________,f____________,and d______ cells

keratinocytes, fibroblasts, dendritic

found protists

leeuenhoek

*WHO* incented microscope and identified protists

leeuwenhoek

HIV => aids when there are less than ____ ___ ____ cells

less than 200 t helper cells

Noroviruses are * (linear/non linear and enveloped / non enveloped)

linear non enveloped

*Viral Genomes* -___________________: (flaviviridae) one long strand of nucleic acid... can be one long or divided into segments -____________________(reoviridae).. -_____________________(circoviridae)... can be ds or ss -___________________(ds circular genome) ONLY VIRUS WITH BROKEN CIRCULAR GENOME : hepadnaviridae.. ds and ss portions of circles -_________________: both + and - rna in one long strand

linear segmented circular gapped ambisense

*WHO* discovered the first animal virus (foor and mouth disease)

loe and fro

what was an interesting symptom of covid-19

lost of taste/smell

symptoms of aids

lymphomas, sarcomas, pneumonia, fungal infections

The Baltimore Scheme - all viruses must make ____ before proteins are made -Once they make ____, they can translate proteins, and then replicate

mRNA

The use of which nucleic acid is common to all viral replication?

mRNA

DS DNAand DS RNA can immediately be made into _______. However, SS __ RNA's genome already acts as mRNA and can be immediately __________-

mRNA translated

SS + RNA acts as what and is immediately what

mRNA translated

*Two important principles of viral genomes* 1. all viral genomes must be copied to produce ______ _______that can be read by the host ribosomes. 2. there is unity in diversity: evolution has led to the formation of only ____ major types of viral genome

mRNA (messenger RNAs) 7

*HIV infects what cells* -cd4 cells, they are found on m___________, t_______, and d_______ cells - hiv is mature (after/before) the viral particle buds off

macrophages, thelper, dendritic after

*Flaviviruses (D.W.Z.Y.)* -entry: RME, fusion with endosomal m_______ -genome: l______, -do they have 5' cap? -do they have poly A tails? -Are they enveloped?

membrane linear yes no YES ENVELOPED

*ss + rna* - all replicate in the cytoplasm, but ss + rna specifically replicate on the m___________ v_______

membrane vesicles

SS + RNA rep occurs where in cytoplasm

membrane vessicles

Virus particles are _____ structures that have not yet attained the minimum free energy conformation

metastable

viruses are m________ structures that have not yet attained the minimum free energy conformation.

metastable

Composition and structure of viral genomes are (more/less) varied than archea, bacteria, and eukaryotes.

more

there are (less/more) ds dna viral families than ss dna

more

How is covid-19 more transmissible?

more efficient s protein cleavage aka replicate fast and overcome innate immune responses

The + strand RNA viruses are the (most/least) abundant

most

are all viruses pathogenic

no

does zika (flavivirus) have a vaccine?

no

is there a cure/vaccine for hiv

no

is there a vaccine for zika?

no

Does the genome of most viruses follow the "one gene, one mRNA" rule? -there (is single/ are multiple) proteins from a single viral genome *** CAN BE

no are multiple

*HIV* -cure or vaccine? therapy?

no cure, no vaccine antiretroviral therapy (slows the replication)

ebola, hep c, and zika have (a vaccine/no vaccine)

no vaccine

how many viruses encode for complete protein synthesis

non

how many viruses encode for energy production and metabolism

non

All virus-receptor interactions are n_____-c_________

non covalent

Adenovirus Does it have an envelope? How does it enter the cell?

non enveloped i. releases specialized proteins (protein VI) that disrupt the endosomal membrane 1. Protein 6, found on inner surface of capsid 2. Once pH drops the capsid disassembles 3. Protein 6 escapes and forms pore in membrane to allow viral genome into cell

structural subunits of the capsid are bonded ___-______

non-covalently

structural subunits bond ___-____

non-covalentyl

picorna viruses are non-_______-

non-enveloped

these are proteins encoded by (all/some/none) viruses 1. COMPLETE PROTEIN SYNTHESIS MACHIENERY 2. energy pdtn 3. metabolism

none

Picornaviruses (polio, entero, rhino) are (linear/nonlinear and enveloped/nonenveloped)

nonlinear non enveloped

what disease is the leading cause of gastroenteritis

noro

which virus can use rdrp to use iether VPG or poly a tail to start replication?

noro

inconvenient illness viruses Diarrhea (_______ &______), colds (________), warts/blisters (H____ and H____)

noro & rota rhino hpv and herpes

*Viruses cause incovenient illness* -Diarrhea (n_______ or r________) -colds (rhino_________) -warts, B______, cold s_________ (HPV, H______ virus)

notovirus, rotavirus, rhinovirus blisters, herpes

A _____ signal or sequence (NLS) is an amino acid sequence that 'tags' a protein for import into the cell nucleus by nuclear transport.

nuclear localization

Proteins that reside within the nucleus are characterized by the presence of specific nuclear targeting sequences. Such ____ signals are both necessary for nuclear entry of the proteins in which they are present and sufficient to direct heterologous, nonnuclear proteins to enter this organelle

nuclear localization

a capsid in an envelope is called a

nucleocapsid

A characteristic feature of a helical structure is that any volume can be enclosed simply by varying the length of the helix. Such a structure is said to be ____ . In contrast, capsids with icosahedral symmetry (described below) are _____ structures with fixed internal volume.

open, closed

noro occurs in outbreaks or isolated

outbreaks

What induced conformational changes in viral capsid?

pH

The receptor may direct the virus particle into endocytic pathways, where uncoating may be triggered by ____ pH or by the action of proteases. This brings the genome into the _____

pH, cytoplasm

DS RNA (packages/encodes) rna dep rna pol, while ss RNA + (packages/encodes) ir

packages encodes

antigenic shift leads to (pandemics/seasonal influenza)

pandemics

Virus entry into cells is not a ______ process but relies on viral usurpation of normal cellular processes, including endocytosis, membrane fusion, vesicular trafficking, and transport into the nucleus.

passive

*WHO* discovered bacteria, looked at the function of bacteria, did fermentation

pasteur

polio, entero, and rhino belong to what fam

picorna

virus means what in latin

poison

*Endocytosis CAN occur without clathrin or caveolin* -ex ______________ -forms an endosome once virus is in side, forms a pore

polio

*ancient viral evidence* -Egyptian: Crippled leg = _______ - Edward Jenner: developed modern ______. Women who worked with cows & got cowpox were immune from smallpox. Took scrapings of cowpox and put it on people. -Lady montague brought this process to england from china -variolation: took scrapings... blew into face of uninfected individual(CHINA)

polio vaccines

which 2 + ss rna viruses have a 5' vpg?

polio and noro

Animal cells cannot copy viral RNAs and make mRNA from them, so the RNA virus must encode NUCLEIC ACID_________

polymerase

dsDNA uses the host DNA _____ to copy their dsDNA

polymerase

SS +RNA make 1 long _______

polyprotein

What is the function of the s protein in coronavirus ?

promotes receptor binding and fusion

What must occur in order for viral envelopes to fuse with cellular membrane during entry? -the viral and cellular membranes must be p______ together -the fusion protein must go through a c________ change -the virus must bind its host c________ receptor

pulled conformational cellular

Life threatening viruses: (RAISE)

rabies, aids (HIV), Influenza, SARS, Ebola

zika can lead to r________ and conj_________, and what in babies

rash, conjunctivis, microcephaly

The r________ molecules on the surface of the virus determine which type of cells the virus can infect

receptor

By convention, the first cell surface molecule that is found to be essential for virus binding is called its _____ . Sometimes, such binding is not sufficient for entry into the cell. When binding to another cell surface molecule is needed, that protein is called a ______.

receptor, coreceptor

Gapped circular dsDNA must be ______ before translation

repaired

the antiretroviral therapy helps people with hiv by slowing what?

replication

Which types of viruses use reverse transcriptase (RT) in their replication cycle? Check all that apply. retroviruses ssDNA viruses ss(-) RNA viruses gapped, circular dsDNA viruses

retroviruses gapped, circular dsDNA viruses

*3 enzymes packaged in HIV virus* 1. R________ _______: rna => ss dna => ds dna 2. I_________: inserts proviral ds dna into nuc & host chromosome. 3. p________: packages the polyprotein into the viral particle after budding (maturation after budding off!!)

reverse transcriptase integrase protease

*replication of RNA viruses* -only RNA viruses have rna d_____ rna p___

rna dependent rna polymerase

Rna viruses encode _ _ _ _

rna dependent rna polymerase

cells have NO rna-dependent RNA pol that can replicate rna viruses or make mRNA from RNA templates. 1. solution is to have RNA virus genomes encode ______ ______ . 2. solution is to have r____- t______- of the genome to ds DNA which can then be transcribed

rna dependent rna polymerases (rdrp) reverse transcription

antigenic drift leads to (pandemics/seasonal influenza)

seasonal influenza

unlike other ss + rna, they do not make only 1 polyprotein, they make ________

several

Where VPg sit on the genome for norovirus? what does it minic?

sits on 5' end of the genome mimics 5' cap

Variolation was widespread in China and India, and was based on the recognition that _____ survivors were protected against subsequent bouts of the disease

smallpox

how many viruses encode to regulate the replication timing

some

these are proteins encoded by (all/some/none) viruses 1. reg of rep timing 2. virual release and spread 3. modulate host immune response

some

The viral attachment of a virus to a host cell is mediated by binding of host receptor and it is ______ . It can include one or more receptors.

specific

Which rna genome structure can -immediately be translated -copy genome ON membrane vesicles -have "-" intermediate - 1 mRNA => polyprotein

ss (+) RNA Viruses

retroviruses are what type of dna

ss + rna

which rna virus is most efficiend and can be directly translated

ss + rna

Retroviruses are ss (+/-) RNA. but they (do/do not) enter genome translation immediately

ss + rna do not

*ss ___ RNA can be directly translated* -ex: n____________ -most e__________ -it is rna so it ENCODES for _____ -*retrovirus encodes rna dependent rna polymerase BUT it also packages ______

ss + rna norovirus efficient rna dependent rna polymerase reverse transvriptase

*HIV error prone* -the virus will change and mutate => new s____ -what do you call host cell preference?

strains tropism

alphaviruses make _____ mRNA that code for ____ proteins

subgenomic structural

A cell that has a functional receptor for a virus but may or may not support viral replication is called _____

susceptible

Virus-receptor interactions can be either promiscuous or highly selective, depending on the virus and the distribution of the cell receptor. The presence of such receptors determines whether the cell will be ______ to the virus. However, whether a cell is _______for the reproduction of a particular virus depends on intracellular components found only in certain cell types.

susceptible , permissive

HIV targets what cells

t helper

*HIV infection* -infects primarily _______ cells -uses two receptors: primary = _______, coreceptor = _________ -entry method: f_______ -reverse transcriptase makes both strands of dna -integrase finds ___dna and takes it to the nuc, inserts HIV into host chromosome (life i_____________) -relies on (its own/ host proteins to replicate) -spliced mrna => polyprotein => packaged by p_______ (this occurs in the viral particle (before/after) budding

t-helper -cd4, ccr5 fusion -ds -infection -host -protease -after

*ss (+) RNA Viruses* -Genome is mRNA, immediately t__________ -Copying of genome occurs ON M________ V_________ -have a n________ intermediate -1mRNA => p____________protein

translated membrane vesicles negative polyprotein

The receptor plays an important role in ______, the process by which the viral genome is exposed, so that gene expression and genome replication can begin

uncoating

where does SARS-CoV-2 primary replicate?

upper respiratory track

Pasteur coined the term ______

vaccination

V__________: inoculation of healthy individuals with material from a viral substance... aka smallpox survivors were protected against subsequent risk of the disease. Lady Montague brought this from China to England.

variolation

this long polyprotein is cleaved by (host/viral) enzymes into individual proteins

viral

From ____ came the principle that the nucleic acid-based repository of the information needed to build, reproduce, and transmit a virus

viral genome

What information is not contained in viral genome?

• genes encoding a complete protein synthesis machinery (e.g., no ribosomal RNA and no ribosomal or translation proteins); note: the genomes of some large DNA viruses contain genes for transfer RNAs (tRNAs), aminoacyl-tRNA synthetases, and enzymes that participate in sugar and lipid metabolism • genes encoding proteins of energy metabolism or membrane biosynthesis • telomeres (to maintain genomes) or centromeres (to ensure segregation of genomes)

What are some gene products and regulatory signals required for viral genome?

• replication of the genome • efficient expression of the genome • assembly and packaging of the genome • regulation and timing of the reproduction cycle • modulation of host defenses • spread to other cells and hosts