virology final

edward jenner

developed smallpox vaccine

enveloped/non-enveloped virus is more stable

non-enveloped;naked

what are the steps of the infectious cycle

1. attachment and entry

2. translation

3. nucleic acid replication

4. assembly

5. release

steps of the replication occur _____

simultaneously

+ssRNA

can go straight into mRNA

-ssRNA

needs to be replicated into +ssRNA for translation; aka retrovirus

baltimore classification classified by _____

nucleic acids

leaky scanning

ribosomes skip the first AUG codon and initiate translation at a downstream AUG

what is a result of leaky scanning?

shorter proteins + allows multiple viral proteins to be made from a single mRNA

ribosomal frameshifting

the ribosome slips back a base and then proceeds --> reading frame is shifted, and a different protein is produced

RNA splicing

removal of introns and joining of exons to form mature mRNA

translational readthrough

ribosomes ignore a stop codon (e.g., UAG) and continue translating

subgenomic RNA

making smaller RNA from larger RNA

mRNA editing

changes in nucleotide seq by addition/deletion/modification of base --> protein translation changes --> changes structure and function of protein

quarantine

separation of healthy individuals exposed to infection

what is the purpose of quarantine?

prevent potential spread during incubation period

isolation

separation of infected individuals from healthy population

what is the purpose of isolation?

prevent direct transmission

endemic

diseases that are persistent in the population at moderate or steady state levels

epidemic

unusually high number of cases in excess of the normal expectation of a similar illness in a population

pandemic

worldwide epidemic

what is a zoonotic disease?

jumps from animals to humans

examples of zoonotic disease

ebola, hep C, influenza, HIV

vector-borne disease

transmitted to humans by vector(mosquito, flea, tick, etc)

example of vector-borne disease

yellow fever

example of non-zoonotic diseases

polio, measles, herpes, variola

examples of non-human viruses

TMV and CTV (plant viruses) and bacteriophage

name 3 innate immune cells

phagocytes, NK(natural killer) cells, dendritic cells

what are the key cells of adaptive immunity?

B cells and T cells

what are the 2 types of T cells?

MHC I: CD8+: cytotoxic killer T cells

MHC II: CD4+: helper T cells

ELISA is used for detecting ______

antigens and patient antibodies

PCR is used to detect ____ for ___ viruses

viral nucleic acids; DNA

plaque assay equation

# of plaques/dilution factor x amount plated in mLs

bacteriophage

virus that infect bacteria

glassy transformation

bacteriophage lyse bacteria in a colony(burst cells) --> colony becomes clear

what are the 4 steps of the one-step growth curve?

1. innoculation = innoculum of virus binds to cells

2. eclipse = virions penetrate the cells

3. burst = host cells release many viral particles

4. burst size = # of virions released per bacterium

what are the 4 steps of bacteriophage infection?

1. adsorption

2. penetration

3. translation and transcription coupled

4. assembly and release

what is a holin?

enzyme used to create pores in inner membrane of host --> allow enzyme to facilitate bacteriophage release

biofilm

permanently attached communities of bacteria

______ can be used to destroy biofilms

bacteriophage

CRISPR role in bacteria

immunity defense

lysogenic conversion

bacteriophage alters phenotype of bacterium and makes it pathogenic(toxic)

lytic phase

bacteriophage kills host cells by lysis/bursting

lysogenic phase

incorporates own DNA/genome into bacterial genome

chimney sweep carcinoma

children exposed to soot --> developed warts and tumors

rous sarcoma virus(RSV)

retrovirus that induces tumor in chickens

examples of oncogenic viruses

hep B(HBV), hep C(HCV), human pap(HPV), epstein-barr(EBV), kaposi's sarcoma-associated herpes(KSHV), human T-lymphotopic 1 and 2(HTLV 1 & 2)

SV40 does ______ replication

bidirectional

in-vivo characteristic of cancer cells

immune evasion

molecular mechanism of cancer cells

retroviruses

cancer

abnormal cells divide without control

matastasis

cell/clump of cells separates from tumor and spreads to another location

cell transformation

the change in the morphological, biochemical, or growth properties of a cell

oncogene(c-onc)

gene that has potential to convert normal cell to cancerous/transformed cell

viral oncogene(v-onc)

viral gene responsible for the oncogenicity of the virus

proto-oncogene

genes that promote normal growth and division of cells

tumor supressor genes

suppress/inhibit conversion of normal cell to cancer cell

what happens when tumor suppressor genes are turned OFF

cause cancer

chronic inflammation/ hep C(HCV) leads to _____

liver cancer

_____ vaccine was the first vaccine to prevent cancer

HBV

HPV transmitted by

sexual contact

gardasil 9 is what type of vaccine

HPV VLP(virus like particle) vaccine

VLPs are NOT infectious because ___

they lack the virus' DNA

monkeypox: zoonotic or not zoonotic?

zoonotic

monkeypox transmission

direct contact with infected animals/person

cowpox: zoonotic or not zoonotic?

zoonotic

____ was used as germ warfare

smallpox

smallpox eradication

mass vaccination + containment via "ring vaccination"

ring vaccination

quickly identifying new cases and vaccinate everyone around

smallpox aka _____

variola virus

vaccina virus

virus used in smallpox vaccine

T/F: variola virus and vaccina virus are the same thing

false

members of poxvirus

smallpox, cowpox, monkeypox, molluscum contagiosum (MCV)

T/F: cholera and scrapie are NOT viral diseases

true

main method of transmission of herpes

direct intimate contact

once HSV integrates into neuron it becomes an ____

episome

acyclovir

herpes drug (HSV-1)

herpesviruses subtypes

EBV, HSV1/2, KSHV/HHV-8, VZV(varicella zoster virus)/HHV-3

how to protect against herpes outbreak?

avoid direct contact + antivirals

HSV-1 affects ____

mouth/oral facial region

which types of influenza occurs in humans and which occurs in animals?

humans: influenza A,B,C

animals: influenza A and D

which influenza strain affects cattle?

influenza D

influenza A viruses are divided into subtypes based on 2 proteins on the surface of the virus called ______

hemagglutinin (HA) and neuraminidase (NA)

what is antigenic drift?

respsonsible for seasonal/localized influenza epidemics due to mutations which are introduced into HA or NA becasue of RdRP's lack of proofreading capability

what is antigenic shift?

2 or more different strains of a virus(one human and one nonhuman) combine to form a new subtype having a mixture of the surface antigens of the original strains

2 influenza subtypes in current circulation

H1N1 and H3N2

influenza host cell receptors

sialic acid receptors

prions

infectious proteins

causative agent of prions

misfolded protein PrPSc --> induces misfolding of normal protein

T/F: prions have an evelope

false

what do viruses have that prions don't

genetic material(DNA/RNA), envelopes, capsid

what do prions have the viruses don't

misfolded host protein, extremely resistant to heat, disinfectants, UV, and proteases

prions transmitted by:

ingestion of contaminated tissues, medical procedures or inherited PRNP gene mutations

transmissible spongiform encephalopathies(TSE)

group of brain and nervous system diseases

what kind of virus is HIV

RNA reverse transcribing virus aka retrovirus

which HIV is more dangerous?

HIV-1 because its transmissible and can mutate more rapidly to AIDS

HIV transmission

sexual contact

HIV+ means:

person has HIV in their body; DOES NOT mean they have AIDS/are infectious

HIV receptor

CD4 receptors

HIV treatment benefits

lowers viral load and patient can live normal life