Biol 240 Topic #5: Viruses

Front 1

Viruses have "" humans....

Back 1

Viral diseases have plagued humans since before we ever knew what they were.

Front 2

"" began as a science in the "" by "".

Back 2

Virology began as a science in the late 1800s by Dimitri Ivanoski.

Front 3

Felix D'Herelle discovered... (Coined term "")

Back 3

Felix D'Herelle discovered bacteriophages (Coined term Plaque)

Front 4

Walter Reed and his colleagues showed that....

Back 4

Walter Reed and his colleagues showed that yellow fever was a virus transmitted by mosquitoes in 1901.

Front 5

Viruses can be defined as...

Back 5

Viruses can be defined as intracellular obligate parasites.

Front 6

Viruses are typically "" and "" nm in size.

Back 6

Viruses are typically 10 and 100 nm in size.

Front 7

A viruses genome is typically "" to "" nucleotides long.

Back 7

A viruses genome is typically a few thousand to 200,000 nucleotides long.

Front 8

(genome size exception) Megavirus chilensis has a genome >"" megabase pairs and encodes "" proteins

Back 8

(genome size exception) Megavirus chilensis has a genome >1.2 megabase pairs and encodes 1200 proteins.

Front 9

The Mimivirus can be "" nm (smallest size of "") in diameter with a "" megabase pair genome coding for "" proteins.

Back 9

The Mimivirus can be 400 nm (smallest size of bacteria) in diameter with a 1.2 megabase pair genome coding for 979 proteins.

Front 10

Pandoravirus has a genome of "" megabase pairs and a "" diameter.

Back 10

Pandoravirus has a genome of 2.5 megabase pairs and a 1 micron diameter.

Front 11

Viruses can have "" or "" DNA or "" ....

Back 11

Viruses can have single or double-stranded DNA or RNA which can be linear or circular.

Front 12

A viruses protein shell ("") (all...) located...is composed of....

Back 12

A viruses protein shell (capsid - all viruses have this) located around the genome is composed of many capsomere proteins.

Front 13

A viruses "" and "" combined is termed... (all...)

Back 13

A viruses capsid and genome combined is termed nucleocapsid. (all viruses)

Front 14

Some viruses have an extra possible "" which come from...

Back 14

Some viruses have an extra possible envelope layer which come from the host cell.

Front 15

Capsids often exhibit either....

Back 15

Capsids often exhibit either helical or icosahedral configurations.

Front 16

The capsid of a virus can also take on...

Back 16

The capsid of a virus can also take on irregular or complex shapes.

Front 17

An Enveloped virus is defined as ...

Back 17

An Enveloped virus is defined as a virus with a plasma membrane surrounding the nucleocapsid.

Front 18

A naked virus (unenveloped virus) is defined as...

Back 18

A naked virus (unenveloped virus) is defined as a virus with no plasma membrane surrounding its nucleocapsid.

Front 19

What are the 6 steps of Viral Replication?

Back 19

1) adhere (stick to host cell through RECEPTOR in the form of protein or polysaccharide not PHOSPHOLIPID)

2)enter (loses the envelope)

3) uncoat (release genome)

4) synthesis (express and replicate genome)

5)assembly (create new virus particle)

6)exit (new particles leave cell - gets new envelope)

Front 20

The process of .... Is the most important part of the viral replication cycle.

Back 20

The process of entering the host cell Is the most important part of the viral replication cycle.

Front 21

When a virus enter a host cell, the "" vary depending on the host cell.

Back 21

When a virus enter a host cell, the mechanisms used vary depending on the host cell.

Front 22

the two mechanisms a virus uses to enter an animal host cell are...

Back 22

1) endocytosis

2) membrane fusion

Front 23

The mechanism a virus uses to enter a plant host cell often depends on...

Back 23

The mechanism a virus uses to enter a plant host cell often depends on the damaged required onto the plant tissue to open a spot in the cell wall.

Front 24

A virus entering a bacterial host cell is similar to a "" where the ... Also, no "" is required

Back 24

A virus entering a bacterial host cell is similar to a hypodermic syringe where the DNA is injected directly into the cell. No ATP is required

Front 25

The lytic bacteriophage replication cycle can be described as ...

Back 25

The lytic viral replication cycle can be described as the phage enters, replicate, and lyse the host cell.

Front 26

The lysogenic bacteriophage replication cycle can be defined as...

Back 26

The lysogenic viral replication cycle can be defined as

1) the phage integrate their genome into host cell genome, becoming a "prophage".

2) phage genome is replicated along with host cells genome until stress.

Front 27

What is the difference between Temperature phage and lytic phage?

Back 27

Temperature phage can be both lytic and lysogenic. Lytic phage are only lytic.

Front 28

(Where did viruses come from?) Coevolution hypothesis states...

Back 28

(Where did viruses come from?) Coevolution hypothesis states viruses originated about the same time as other microves and have beeen coevolving with them

Front 29

(where did viruses come from?) Regressive Hypothesis states....

Back 29

(where did viruses come from?) Regressive Hypothesis states viruses are previously alive organisms that have evolutionarily regressed into host-dependent particles.

Front 30

(where did viruses come from) Progressive Hypothesis states...

Back 30

(where did viruses come from) Progressive Hypothesis states viruses originated from genetic material that gained the ability to replicate and be transmitted semi-autonomously.

Front 31

What are the four general steps of cultivating bacteriophage?

Back 31

1) small volume of susceptible bacterial host cell added to phage sample.

2)mixture is added to molten nutrient agar and quickly mixed.

3) agar mixture poured into nutrient agar base and allowed to solidify.

4)plaques appear aftee sufficient incubation .

Front 32

Cultivating bacteriophage is much trickier to work with... Because... And...

Back 32

Cultivating bacteriophage is much trickier to work with bacteria Because very small and need specific hosts.

Front 33

In cultivating animal viruses, ... Is used to grow ....

Back 33

In cultivating animal viruses, tissue culture of host cells Is used to grow targets for the viruses.

Front 34

(cultivating animal cells) the tissue culture of host cells must be kept... And....

Back 34

(cultivating animal cells) the tissue culture of host cells must be kept sterile And bacteria free.

Front 35

Method for cultivating animal viruses have only been in place since the...

Back 35

Method for cultivating animal viruses have only been in place since the 1950s.

Front 36

Modern "" couldn't exists without...

Back 36

Modern Virology couldn't exists without cultivating animal virus methods.

Front 37

The method of cultivating animal viruses were mainly developed from a ... known as...

Back 37

The method of cultivating animal viruses were mainly developed from a first human cell line known as HeLa cells.

Front 38

Viral purification usually begins with... The viruses are then...

Back 38

Viral purification usually begins with simple filtration to remove large cells and cellular debris. The viruses are then purified and concentrated with centrifugation.

Front 39

(viral purification) what are the three steps of differential centrifugation?

Back 39

1) begin with low speed centrifugation.

2)transfer supernatant and centrifuge at medium speed.

3)transfer supernatant and centrifuge at high speed.

Front 40

(virus purification) gradient centrifugation depends on ... The viruses have much...

Back 40

(virus purification) gradient centrifugation depends on the different densities of viral components and particles. The viruses have much higher densities than other particles.

Front 41

(virus purification) what are the three steps of gradient centrifugation ?

Back 41

1)tube successfully filled with layers of decreasing concentrations of sucrose.

2) suspension containing virus is layered on top.

3) preparation is centrifuged .

Front 42

Viral quantification is not...or...

Back 42

Viral quantification is not easy or straightforward.

Front 43

Viral Quantification is usually measured as a...

Back 43

Viral Quantification is usually measured as a titer, or concentration of a virus preparation.

Front 44

What are the four method of Viral Quantification ?

Back 44

1) direct count

2) hemagglutination assay (specific to human viruses)

3) plaque assay

4) endpoint assay

Front 45

(viral quantification ) in the direct count method, a... Used to...

Back 45

(viral quantification ) in the direct count method, a electron microscope is used to visualize a known volume of material.

Front 46

(virus quantification) in the direct count method, viruses within a known volume of material are ... And..

Back 46

(virus quantification) in the direct count method, viruses within a known volume of material are counted And scaled up to determine titer.

Front 47

(virus quantification ) the direct count method requires an... And doesn't differentiate between...

Back 47

(virus quantification ) the direct count method requires an expensive, specialized microscope And doesn't differentiate between infectious and non infectious viral particles.

Front 48

(viral quantification) the Hemagglutination method exploits....causing....

Back 48

(viral quantification) the Hemagglutination method exploits traits of some viruses (mostly human viruses) to stick to red blood cells, causing them to form a gel mat.

Front 49

(virus quantification) the hemagglutination is ...,...,..., and no...is required.

Back 49

(virus quantification) the hemagglutination is cheap, easy, fast and no microscope is required.

Front 50

(virus quantification ) using the hemagglutination method, some viruses.... Also, it doesn't differentiate ....and doesn't give a...

Back 50

(virus quantification ) using the hemagglutination method, some viruses won't do this . Also, it doesn't differentiate viable/ non viable viruses and doesn't give a virus count.

Front 51

(Virus quantification)What are the two main steps of the Plaque Assay method?

Back 51

1) virus is diluted and placed on target cells

2) plaques are counted to determine plaque-forming unit (PFU) titer of original suspension.

Front 52

The Plaque Assay method is useful in... and...

Back 52

The Plaque Assay method is useful in bacteriophages and plant viruses.

Front 53

(Endpoint Assay) A tissue culture infectious dose 50 (TCID 50) is the amount of virus needed...

Back 53

(Endpoint Assay) A tissue culture infectious dose 50 (TCID 50) is the amount of virus needed to induce a CPE (cytopathic effect) in 50% of cultured cells.

Front 54

(Endpoint Assay) A lethal dose 50 (LD 50) is the amount of virus needed...

Back 54

(Endpoint Assay) A lethal dose 50 (LD 50) is the amount of virus needed to kill 50% of test animal subjects.

Front 55

What are the Five types of Virus naming ?

Back 55

1) Simple letter/number combinations

2) Organism(s) they infect

3) Location of discovery

4) Appearance

5) Disease caused

Front 56

ICTV stands for...

Back 56

ICTV stands for International Committee on Taxonomy of Viruses

Front 57

ICTV (International Committee on Taxonomy of Viruses) is used to classify viruses based on: (7)

Back 57

ICTV (International Committee on Taxonomy of Viruses) used to classify viruses based on:

1) Order

2) Family

3) Subfamily

4) Genus

5) Species Morphology

6) Genome Structure

7 Biological Features

Front 58

The Baltimore Classification System is a virus classification system based around...

Back 58

The Baltimore Classification System is a virus classification system based around mRNA production methods.

Front 59

The Baltimore Classification System separates viruses into...

Back 59

The Baltimore Classification System separates viruses into Seven classes.

Front 60

The Baltimore Classification system was developed by...

Back 60

The Baltimore Classification System was developed by Nobel Laureate David Baltimore.

Front 61

( Virus Identification) The first step in virus identification is.... then afterwards ....

Back 61

(Virus Identification) The first step in virus identification is Electron Microscopy then afterwards visual observation on viral morphology (not infallible)

Front 62

Nucleic Acid Analysis for virus genome can be done through both ... and...

Back 62

Nucleic Acid Analysis for virus genome can be done through both PCR and reverse-transcriptase PCR.

Front 63

Nucleic Acid Analysis (PCR and Reverse Transcriptase PCR) is used to identify.... and also study...

Back 63

Nucleic Acid Analysis (PCR and Reverse Transcriptase PCR) is used to identify viruses by genome sequence and also used to study viral evolution patterns.

Front 64

What are Five features of Viroids?

Back 64

1) Consist of only naked RNA.

2) Extremely small (less than 400 nucleotides)

3) High degree of internal complementarity

4) resistant to ribonucleases

5) so far, only observed to cause disease in plants.

Front 65

Prions are ..... particles.

Back 65

Prions are Proteinaceous infectious particles.

Front 66

What are three features of Prions?

Back 66

1) Bodily composition of just protein. No nucleic acid, no genes,.

2) are a variety of different "infectious" agents

3) Responsible for transmissible spongiform encephalopathies (TSE), such as mad cow disease and creutzfeld - jakobs disease in humans.

Front 67

Prions "" is still unclear. They are though to revolve around conversion of...

Back 67

Prions replication method is still unclear. They are thought to revolve around conversion of protein conformations from normal to abnormal form over time.

Front 68

(Virology Today) "" and "" are closely involved.

Back 68

(Virology Today) Virology and Medicine are closely involved.

Front 69

How is virology and medicine closely involved ?

Back 69

1) cancer-causing oncoviruses

2) cancer-destroying oncolytic viruses

3) gene therapy

Front 70

(Virology Today) Virology continues to be involved in...

Back 70

(Virology Today) Virology continues to be involved in examination of emerging global diseases.

Front 71

How did virology begin through Dimitri Ivanoski in the 1800s ?

Back 71

How did virology begin through Dimitri Ivanoski in the 1800s ?

Dimitri isolated infectious tobacco mosaic virus in filtered, bacteria-free fluid.

Front 72

All viruses have "" made mostly .... They are usually only a few "" up to..

Back 72

All viruses have a genome made mostly of nucleic acid. (not all cause of prions) They are usually only a few genes until a few hundred genes.

Front 73

Ameoba is the collective host cell.... and ""

Back 73

Ameoba is the collective host cell of Megavirus Chilensis, Mimivirus, and Pandora virus and X-bacteria.

Front 74

"" shape is common for RNA viruses. This is because RNA is... and the capsid...

Back 74

Helical shaped capsid is common for RNA viruses. This is because RNA is very sensitive in the environment and the capsid covers and protects the RNA.

Front 75

Helical capsids are exactly.... - exact relation

Back 75

Helical capsids are exactly the length of the RNA genome. - exact relation

Front 76

What are 3 features of icosahedral capsid?

Back 76

What are 3 features of icosahedral capsid?

- Soccer ball shaped

- Very hard for capsid molecules to build icosahedral shape.

- Different planes of symmetry are possible.

Front 77

The "" is a common bacterial virus (especially ""). Its... into host.

Back 77

The T4 bacteriophage is a common bacterial virus (especially E.Coli). Its tail helps inject DNA into host.

Front 78

An enveloped virus obtains the envelope as..... The virus only needs the envelope...

Back 78

An enveloped virus obtains the envelope as it leaves the host cell. The virus only needs the envelope when it leaves one host and gets into another - THATS IT!

Front 79

(Viral Replication) Viruses are extremely familiar....such that...

Back 79

(Viral Replication) Viruses are extremely familiar with their host cell such that they know where to attach to.

Front 80

(Entering Cell) HIV almost always binds to "" on "" cells.

Back 80

(Entering Cell) HIV almost always binds to CD4 receptors on T cells.

Front 81

What is the relation of Entering animal cells between Naked and Enveloped viruses? Is ATP required?

Back 81

What is the relation of Entering animal cells between Naked and Enveloped viruses?

- Naked virus can only do Endocytosis

- Enveloped virus can do both Endocytosis and Membrane fusion.

-No ATP is required.

Front 82

What are different ways Plant tissue can be damages (so virus can enter) ? (5)

Back 82

What are different ways Plant tissue can be damages (so virus can enter) ? (5)

- insects feeding on plants ****

- wind damage

- hail/rain damage

- fire damage

- human-induced damage

Front 83

What is 3 step process of Entering Bacterial Cell for viruses? Is ATP required?

Back 83

What is 3 step process of Entering Bacterial Cell for viruses? Is ATP required?

1 - tail fibers attach to bacterial cell surface

2- virus injects core into the plasma

3- then genome is transferred.

No ATP is required.

Front 84

"" only infect bacteria.

Back 84

Bacteriophage only infect bacteria.

Front 85

All viruses rely on host... ("" activity) ("" --> "")

Back 85

All viruses rely on host for TRANSLATION (ribosome activity) (mRNA --> proteins)

Front 86

SARS, also known as ... is caused by...

Back 86

SARS, also known as severe acute respiratory syndrome is caused by a new coronavirus.

Front 87

(Nucleic acid analysis) Nucleic acid analysis is the most...

Back 87

(Nucleic acid analysis) Nucleic acid analysis is the most powerful approach in identifying a new virus.

Front 88

Give a brief description of CRISR - Cas system in bacteria

Back 88

Give a brief description of CRISR - Cas sytem in bacteria

When a bacterial cell is exposed to virus and it doesn't die, then CRISPR will identify this virus and the NEXT time the virus comes around the bacteria eliminates the virus.