Introduction to Virology Flashcards by Franchez Cassandra Escander

comprise an enormous proportion of our environment

viruses

How well did you know this?

Not at all

Perfectly

Current estimates of the number of individual viruses
on earth
- considerably exceed the total number of
stars in the known universe that is

100 sextillion

How well did you know this?

Not at all

Perfectly

biomass of bacterial viruses exceeds all of Earth’s
___by more than 1,000
-fold

elephants

How well did you know this?

Not at all

Perfectly

more than 10^30 ___particles in the world’s
oceans,

bacteriophage

How well did you know this?

Not at all

Perfectly

also known informally as a phage is a virus that infects and replicates within bacteria and archaea

bacteriophage

How well did you know this?

Not at all

Perfectly

average human body contains approximately 10^13
cells, outnumbered 10
-fold by ___ and as much as
100
-fold by ___particles.

bacteria
virus

How well did you know this?

Not at all

Perfectly

are loaded with myriad plant and
insect viruses, as well as hundreds of bacterial species
that harbor their own constellations of viruses.

intestinal tracts

How well did you know this?

Not at all

Perfectly

most devastating human diseases have been or
still are caused by

viruses

How well did you know this?

Not at all

Perfectly

deadly viruses

small pox
yellow fever
poliomyelitis
influenza
measles
AIDS

How well did you know this?

Not at all

Perfectly

Viruses are responsible for approximately __%
of the human cancer burden

How well did you know this?

Not at all

Perfectly

541–542 Pandemic

Plague of Justinian

How well did you know this?

Not at all

Perfectly

Plague of Justinian is caused by

Y. pestis

How well did you know this?

Not at all

Perfectly

1346–1350 pandemic causing 75-200M deaths

Black Death

How well did you know this?

Not at all

Perfectly

The Black Death is caused by

Yersinia pestis

How well did you know this?

Not at all

Perfectly

1899–1923 pandemic causing 75 million deaths

sixth cholera pandemic

How well did you know this?

Not at all

Perfectly

sixth cholera pandemic is caused by

vibrio cholerae

How well did you know this?

Not at all

Perfectly

1918–1920 pandemic causing 100 million deaths

spanish flu

How well did you know this?

Not at all

Perfectly

spanish flu is caused by

H1N1

How well did you know this?

Not at all

Perfectly

h1n1 is also sometimes known as

swine flu

How well did you know this?

Not at all

Perfectly

1957–1958 pandemic causing 1-4 million deaths

asian flu

How well did you know this?

Not at all

Perfectly

asian flu is caused by

h2n2

How well did you know this?

Not at all

Perfectly

1968–1969 pandemic causing 1 million deaths

Hong Kong Flu

How well did you know this?

Not at all

Perfectly

2009–2010 pandemic causign 151,700-575,400 deaths

swine flu

How well did you know this?

Not at all

Perfectly

swine flu is caused by

h1n1

How well did you know this?

Not at all

Perfectly

2020 pandemic causing 6,794,272 deaths

COVID-19

COVID-19 is caused by

SARS-Cov-2

____ account for an estimated 12% to 20% of cancers worldwide.

human tumor viruses

virus that cause Burkitt’s Lymphoma, Hodgkin’s Disease, and Nasopharyngeal Carcinoma

Epstein-Barr virus

virus that cause Cervical Carcinoma, Anal Carcinoma, Oropharyngeal Carcinoma, Penile Carcinoma

Human Papillomaviruses 16 and 18

viruses that cause Kaposi’s Sarcoma, Primary Effusion Lymphoma, Multicentric Castleman’s Disease

Kaposi's Sarcoma-Associated Herpesvirus

virus that cause Hepatocellular Carcinoma

Hepatitis B virus and Hepatitis C virus

virus that cause T-cell Leukemia

Human Adult T-cell Leukemia Virus Type 1 (HTLV-1)

virus that causes Merkel Cell Carcinoma

* Merkel Cell Polyomavirus

reduction of a wild animal population by selective slaughter

culling

2011 outbreak hit the entire ___ peninsula and resulted in the culling of nearly 3.5 million cattle, pigs and other animals in South Korea alon

Korean

culling of cattle, pigs, and other animals in south Korea was done to

prevent spread of swine flu

Specific for each invertebrates, vertebrates, plant, fungi, bacteria

host range and requirements

host range and requirements Requires specific ___ on the host cell

attachment

If there is no ___ ___complex, then there is no viral infection happening

attachment receptor

receptor sites for viruses

cell wall fimbriae flagella

are a;achments for animal virus.

cell membranes

orchid leaves has symptoms of ringspots resulting from a strain of ____

tobacco mosaic virus

Infected ___excrete more than 1013 calicivirus particles daily.

whales

Infected whales excrete more than 1013 ____particles daily.

calicivirus

viruses comprise 94% of all ____ ____-containing particles in the oceans …15 times more abundant than the Bacteria and Archaea.

nucleic acid

Viral infections in the ocean kill 20 to 40% of marine microbes daily…release essential nutrients that supply ___at the bottom of the ocean’s food chain, as well as carbon dioxide and other gases that affect the climate of the earth

phytoplankton

mice latently infected with some murine _____are resistant to infection with the bacterial pathogens Listeria monocytogenes and Yersinia pestis.

herspevirus

mice latently infected with some murine herpesviruses are resistant to infection with the bacterial pathogens ___ and ___

Listeria monocytogenes Yersinia Pestis

what is the term for cross-species infections of humans are occurring with increasing frequency

zoonotic

are recent examples of viral diseases to emerge from zoonotic infections.

ebola hemorrhagic fever SARS

zoonotic diseases can be spread through (5)

direct indirect vector-borne foodborne waterborn

Hand, foot, and mouth disease (HFMD) is caused by a virus in the enterovirus family, most commonly the

coxsackievirus A16

* Every cell in our body contains ___ DNA

viral

what viruses make up about 5 to 8% of our DNA

human endogenous retroviruses

how did human endogenous retroviruses make up 5 to 8 percent of our DNA

* from infections of germ cells that have occurred over millions of years during our evolution

it becomes part of a host's genome when it injects its DNA into the host's cells, especially germlike cells like sperm or eggs.

virus

* conservation of some of the viral sequences in ___ genomes suggests that they may have been selected for beneficial properties over evolutionary time

vertebrate

When researchers began to analyze the human genome, they found that about ___ percent of the genetic code that's there actually came from viruse

mechanism of virus when they infect humans

A virus injects its DNA into a host cell The virus uses enzymes to convert its RNA genes into DNA The virus uses enzymes to cut into the host's chromosomes The viral DNA embeds itself into the host's chromosomes The host cell copies its own DNA, including the viral DNA The viral DNA can be passed on to the next generation

non coding DNA and RNA sequences that are removed from a gene during the process of RNA splicing

introns

segments of DNA that are transcribed into RNA and become part of a mature messenger RNA (mRNA) molecule

exons

are important since it allows a single gene to code for multiple proteins with different functions, thus increasing the complexity of gene expression and adaptation within an organism; they can also act as regulatory elements influencing transcription and mRNA stability

intervening sequences

the process of removing non-coding regions of DNA, called introns, to produce a mature mRNA that codes for proteins.

splicing

studies that focus on viral ____ of cellular mechanisms have provided unique insights into cellular biology and functioning of host defenses.

reprogramming

led to the understanding that DNA carries the genetic information, a foundation of modern molecular biology

study of bacteriophages

Studies of ___viruses established many fundamental principles of cellular function, including the presence of intervening sequences in eukaryotic genes.

animal

study of ____(____) viruses revealed the genetic basis of this disease.

cancer (Transforming)

viral genomes as vehicles for the delivery of ___to cells and organisms for both scientific and therapeutic purposes.

genes

are to introduce genes into various cells and organisms to study their function has become a standard method in biolog

viral vectors

___ ___ are the foolproof methods to identify the microorganism

genetic studies

therapeutic use of viruses included

gene therapy vectors immunogens for vaccine oncolytic virotherapy novel therapeutic proteins

Virus in humans from ___ of animals than in ___

domestication hunting

Viruses in ___ tropic are endemic.

tropics

exposure to viruses more common in ___ than in temperate climates

tropics

Viruses established in what size of communities

large,settled

Less virulent viruses such as ___ (3) enter into a long term relationship with their hosts, first to become adapted to reproduction in the earliest human populations

modern retroviruses herpesviruses papillomaviruses

mycotymovirus has little to no effect on host fungus called

Fusarium graminearum

An image of “rabid” ___from an ancient Greek vase

hector

An Egyptian stele, or stone tablet… depicting a man with a withered leg and the “drop foot” syndrome characteristic of

polio

aws that outline the responsibilities of the owners of rabid dogs date from before 1000 B.C.

mesopotamian

probably endemic in the Ganges River basin by 500BC. and subsequently spread to other parts of Asia and Europe, has played an important part in human history.

small pox virus

smallpox virus … probably endemic in the ___River basin by 500BC. and subsequently spread to other parts of Asia and Europe, has played an important part in human history.

Ganges

Other viral diseases known in ancient times include

mumps influenza

suggested to have caused the scourge of the tropical trade - basis for legends about ghost ships, such as the Flying Dutchman, in which an entire ship’s crew perished mysteriously.

yellow fever

cultivation of marvelously patterned ___ , which were of enormous value in 17th-century Holland

tulips

inoculation of healthy individuals with material from a smallpox

variolation

fatality rate when variolated

1-2%

fatality rate of adults and babies with variola when naturally infected

25% (40% in babies)

variolation is widespread in which countries by the 11th century

China and India

variolation is introduced in ___ in 1721

England

variolation is introduced to the US army in 1776 by

George Washington

used cowpox infected material obtained from the hand of Sarah Nemes, a milkmaid from his home to successfully vaccinate James Phipps

Edward Jenner

first deliberately attenuated viral vaccine

Louis Pasteur

inoculated rabbits with material from brain of cow suffering from rabies and then used aqueous suspensions of dried spinal cords from these animals to infect other rabbits.

Louis Pasteur

resulting preparations caused mild disease (i.e., were attenuated) yet produced effective immunity against rabies

vaccination

a vaccine for __ ___ virus was developed in 1935, and an ___ vaccine was available in 1936.

yellow fever influenza

The word "vaccine" comes from the Latin word vacca, which means "cow". English physician Edward Jenner coined the term after he discovered that ___could prevent smallpox

cowpox

Koch's postulate 1

The organism must be regularly associated with the disease and its characteristic lesions.

koch postulate 2

The organism must be isolated from the diseased host and grown in culture.

koch postulate 3

The disease must be reproduced when a pure culture of the organism is introduced into a healthy, susceptible host.

koch postulate 4

The same organism must be reisolated from the experimentally infected host (Box 1.4).

“ failures of the paradigm that bacterial or fungal agents are responsible for all diseases led to the identification of a new class of infectious agents— submicroscopic pathogens that came to be called ___.

viruses

first virus to be discovered

tobacco mosaic virus

when did TMV discovered

1895

latter part of the 20th century, new methods developed to associate particular viruses with disease based on ____ evidence of infection.

immunological

virus cultivation cannot be used in culture-____methods, but instead culture-____methods

dependent independent

high-throughput nucleic acid sequencing methods and bioinformatics tools allow detection of viral genetic material directly in environmental or biological samples - approach called

viral metagnomics

Thus, “metagenomic Koch’s postulates” have been proposed (2)

(i) using molecular markers such as genes or full genomes to detects samples from diseased subjects from that of healthy control subjects (ii) inoculating a healthy individual with a sample from a diseased subject results in transmission of the disease as well as the molecular markers.

metagenomic koch's postulate 1 states (i) using ___ ____ such as genes or full genomes to detects samples from diseased subjects from that of healthy control subjects ;

molecular markers

metagenomic koch's postulate ii) inoculating a healthy individual with a sample from a diseased subject results in transmission of the ____ as well as the ____ markers.

disease molecular

in 1886, he showed that tobacco mosaic disease was transmissible

Adolf Mayer

in 1892, he i filtered sap of diseased tobacco and found that the agent passed through the porcelain filter – no identification

Dmitri Ivanowski

in 1898, he termed the submicroscopic agent responsible for tobacco mosaic disease contagium vivum fluidum - an infectious fluid

Beijenrick

when did Beijenrick term the submicroscopic agent responsible for tobacco mosaic disease

1898

tobacco mosaic disease is termed what by Beijenrick

contagium vividum fluidum

“infectious filterable agents comprised small particle" who stated in 1898

Friedrich Loeffler and Paul Frosch

came to the same conclusion regarding the cause of foot-and mouth disease; could be passed from animal to animal, with great dilution at each passage, the causative agent had to be reproducing and thus could not be a bacterial toxin.

Friedrich Loeffler and Paul Frosch

discovered viruses that cause chicken leukaemia in 1908

Ellerman and Bang

s discovered that solid tumours of chickens could be transmitted by cell-free filtrates - first indications that some viruses can cause cancer

Rous

– bacteria as host to viruses by

Twort

– discovered and named bacteriophages (bacteria eater) by

D'Herelle

isolated the tobacco mosaic virus

Wendell Stanley

extensively purified tobacco mosaic virus and showed it to be nucleoprotein containing ribonucleic acid (RNA).

Bawden and Pirie

worked with the viruses called bacteriophages (because they “eat” bacteria), in the early 1940s.

Max Delbruck Salvador Luria

found that phages infect bacteria and multiply within them until they filled the cells, which then burst open. They also found that the phages consisted entirely of DNA and protein, like chromosomes.

Max Delbruck Salvador Luria

phages consisted entirely of

DNA and protein (like chromosomes)

application of cowpox virus for vaccination agaisnt smallpox, inflammation origins of virology and immunology

Edward Jenner

Development of Rabies Vaccine

Louis Pasteur Emile Roux

first demo of filterable plant virus: tobacco mosaic virus

D. Ivanovsky M. Beijenrick

first demo of filterable animal virus: foot and moudh disease virus

F. Loeffler P. Frosch

first filterable plant virus

tobacco mosaic virus

first filterable animal virus

foot and mouth disease virus

first human virus

yellow fever virus

discovered yellow fever virus, first use of consent form for human clinical investigation, identify mosquito as transmitting agent, control of virus by elimination of mosquito breeding sites

J. Caroll J. Lazear A. Agramonte W. Reed C. Finlay W. Gorgas

first demonstration of leukemia causing virus retrovirus

V. Ellerman O. Bang H. Vallee H. Carre

leukemia causing virus

retrovirus

first report of virus causing immunosuppression

C. von Piquet

virus causing immunosuppression

c. Von Piquet

isolation of poliomyelitis irus

K. Landsteiner E. Popper

discovery of measles virus

J. Goldberger

first demonstration of a stolid tumor virus: Rous Sarcoma Virus

P. Rous

discovery of bacteriophages

F. Twort

Bacteriophages, plaque assay

F d'Herelle

used 16s rRNA gene for the three domains but viruses do not have.

Carl Woese

provide evidence that the association between viruses and their hosts is as ancient as the origin of the hosts themselves

amino acid sequences of viral and cellular proteins and that of the nucleotide sequences of the genes

says viruses have no relics of ribosomal proteins or having encoded enzymes for energy metabolism

genetic evidence

Analysis of the sequence relationship between various retro- viruses found in mammalian genomes demonstrates ____ of some types before major groups of mammals diverged.

integration

A hypothesis for DNA viruses as the origin of eukaryotic ___ ____

replication protein

viruses were presented entirely in negative things such as:

they could not be seen * could not be cultivated in the absence of cells and, * most important of all, were not retained by bacteria- proof filters.

key characteristic of viruses

: they are small parasites that require a host in which they replicate.

elative ease with which tobacco mosaic virus could be crystallized was a direct result of both its structural ___ and the ability of many particles to associate in __ ___

simplicity regular arrays

viruses are shaped as

helical or spherical

absolute dependence on a living host for reproduction: they are

obligate parasites

*Transmission of plant viruses by applying ___of an infected plant to a scratch made on the leaf of a healthy plant

extracts

Lab animals as tool for investigation; developments thru __ ___systems were used

cell culture systems

example of cell culture systems

bacterial cells cell lines

. viral genome comprises

DNA or RNA

as subject in the determination of DNA as carriers of hereditary information in Hershey and Chase's experiment

bacteriophage

process where viruses convert RNA to DNA (

reverse transcription

viruses convert RNA to DNA (reverse transcription) needs the enzyme

reverse transcriptase

directs the synthesis of viral components by cellular systems within an appropriate host cell

viral genome

In this phase, the virus exists outside of a host cell. It's essentially inert and doesn't show any signs of life

inanimate phase

Once a virus infects a host cell, it enters the

multiplying phase

. Infectious progeny virus particles, called

virions

, are formed by de novo self-assembly from newly synthesized components.

virions

being the vehicle for transmission

virions

viruses lack cellular characteristic and is therefore classified as ___

subcellular

size of viruses

20-1000 nm

virust particle

virion

virus Have few or no ____for metabolism – direct cell machinery for its own use

enzymes

genetic material of virus can be

DNA or RNA

virus can have ___ or ___ stranded RNA/DNA

single double

how many proteins does viruses code at most

viruses has ___ surrounding the n.a.

protein coat

viruses can have an envelope made of ___

phospholipids

viruses are ___, meaning they must be inside a host to multiply

obligate intracellular parasites

can viruses be grown on culture media?

can integrate to host genes - conversion to cancer cells

viral genes

units commonly used in descriptions of virus particles or their components are the ___ and the ___

nanometer and angstrom

viruses can be seen using what microscope

light (some) electron microscope (all)

etiologic agent of COVID-19

Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2)

size of SARS-CoV-2

140 nm

* Around the world, health officials have agreed that wearing ___can prevent the spread of the virus between individuals.

mask

…remove at least 95% of all particles with an average diameter of 300 nm or less

n95 masks

acellular infectious agents include

prions viruses

cellular microorganisms include

prokaryotes (archaea and bacteria) eukaryotes (algae, fungi, protozoa)

intracellular parasites? Typical Bacteria Rickettsias Chlamydias Viruses

TB - No R - Yes C - Yes V - Yes

intracellular parasite that is a bacteria

rickettsias and chlamydias

plasma membrane Typical Bacteria Rickettsias Chlamydias Viruses

T - Yes R - Yes C- Yes V - No

Typical Bacteria Rickettsias Chlamydias Viruses binary fission

T - Yes R- Yes C - Yes V - No

Typical Bacteria Rickettsias Chlamydias Viruses pass through bacteriological filters

T - no R - no C - Yes V - Yes

Typical Bacteria Rickettsias Chlamydias Viruses possess both DNA and RNA

T - Yes R - Yes C - Yes V - No

ATP generating metabolism Typical Bacteria Rickettsias Chlamydias Viruses

T - YEs R - Yes C - No V - No

Typical Bacteria Rickettsias Chlamydias Viruses ribosomes?

T - Yes R- Yes C - Yes V - No

Typical Bacteria Rickettsias Chlamydias Viruses sensitive to antibiotics

T - Yes R - Yes C - Yes V - No

Typical Bacteria Rickettsias Chlamydias Viruses sensitive to interferon

T R C - no V - yes

SarsCOV contain either __ or __ as genetic material

DNA or RNA