Exam 2 Viruses

Question 1

What does virus mean and who named it

Answer 1

pasteur named it
Means poison

Question 2

What was the first virus discovered

Answer 2

The tobacco Mosaic virus in 1935

Question 3

All viruses are considered obligate blank blank

Answer 3

Intracellular parasites

Question 4

What are the two components that make up the structure of a virus

Answer 4

One type of nucleic acid either RNA or DNA but not both

Surrounded by a protein coat

Question 5

What does the host range of a virus refer to?

Answer 5

The spectrum of hosts that the virus can infect

Question 6

What does it mean to cross host range barriers?

Answer 6

The virus can cross to other species

Question 7

What are bacteriophage also known as phages?

Answer 7

Viruses that can affect bacteria

Question 8

Why must a bacteria interact with receptors?
What can receptors do?

Answer 8

In order for a virus to enter a cell, it must interact with receptors

However, receptors can change shape to accommodate the virus

Question 9

What are oncolytic viruses

Answer 9

Viruses that attack tumors

Question 10

What type of equipment determines a virus’s size?

Answer 10

An electron microscope and the size is typically 20 to 1,000 nanometers

Question 11

What is a virion?

Answer 11

A complete fully developed infectious particle

It’s made of a capsule and nucleic acid
It’s considered a fully developed virus

Question 12

What type of nucleic acid does a virus use?

Answer 12

Rna or DNA but not both

Question 13

What type of nucleic acid often makes him more virulent virus

Answer 13

Rna

Question 14

What is the shape of RNA versus DNA in a virus?

Answer 14

Rna is linear
DNA is circular

Question 15

What is a capsid

Answer 15

The protein coat on the outside of a virus

Question 16

What is a capsomere?

Answer 16

Subunits of the protein coat

Question 17

Why is the capsid arrangement important

Answer 17

It is used to identify the virus

Question 18

What is a virus envelope and how often do we see it

Answer 18

It is a covering over the capsid and some viruses have it but some do not

Question 19

What is the composition of a virus in chemistry terms

Answer 19

Phospholipid bilayer proteins and a few carbs

Question 20

What are the two ways of a virus being created by the host cell

Answer 20

Formed by the host cell membrane as the virus exits

Assembled by the host cell

Question 21

How does The new copies of the virus leave the cell in the lytic cycle

Answer 21

They rupture through the cell membrane

Question 22

How does the lysogenic cycle create new viruses?

Answer 22

The virus takes over the cell and the viral DNA or RNA tells the cell to make an outer coat for the new viruses

Question 23

What do the spikes do on a virus

Answer 23

Allow it to attach to the cell membrane of the host cell

Question 24

What is agglutination?

Answer 24

Clumping of the host cells via attachment to the spikes of a virus

Question 25

How does a non-envelope virus attach to the host cell?

Answer 25

The capcid attaches to the host cell and injects in the DNA or RNA but not the capsid

Question 26

What is the capsid?

Answer 26

The protein coat on the outside of the virus

Question 27

Define morphology

Answer 27

The shape of something

Question 28

What is the morphology of a helical capsid with example?

Answer 28

The capsid is a hollow of cylinder Examples are Ebola and rabies

Question 29

What is the morphology of a polyhedral capsid with example?

Answer 29

Icosahedron meaning 20 triangular faces and 12 corners Example is polio

Question 30

What is the morphology of an enveloped capsule with example?

Answer 30

It is usually spherical If it is helical, an example would be influenza If it is polyhedral, an example would be herpes

Question 31

What is making the influenza virus worse?

Answer 31

Mutation

Question 32

What is the name of the herpes virus

Answer 32

Hsv1 Herpes simplex virus 1 and herpes simplex virus 2

Question 33

In the taxonomy of viruses, what is symptomatology?

Answer 33

Classifying viruses based on the type of disease they cause

Question 34

What do we currently base our taxonomy of viruses on Three things

Answer 34

Nucleic acid type such as RNA or DNA Replication means such as lytic or lysogenic Morphology

Question 35

What taxonomy terms do we use when classifying viruses

Answer 35

Order family genus species

Question 36

What is considered a viral species?

Answer 36

Viruses that share the same genetic information and host range

Question 37

What are viral plaques?

Answer 37

Dead bacteria killed by viruses. Clear zones on a medium like a plate indicates area where virus has destroyed the bacteria

Question 38

What is needed for a virus to be replicated or cultivated?

Answer 38

Living cells

Question 39

What type of medium is a bacteriophage grown in?

Answer 39

A liquid medium or on a solid

Question 40

What is a theoretical count of viruses

Answer 40

An educated guess. Every plaque represents one virus Particle

Question 41

What is a plaque forming unit or PFU

Answer 41

How many plaque spots you have? It will report the theoretical count

Question 42

What is commonly used for isolation, cultivation and identification of animal viruses initially Then what did it change to? Finally, what is used now for this purpose?

Answer 42

Mice rats and guinea pigs initially It was changed to embryonated eggs Currently cell cultures are used

Question 43

How do you determine if a embryonated egg has a virus and how does a virus get in it?

Answer 43

You inject the virus into the eggs duck's goose or chicken, eggs or common Growth of the virus is signaled by death or damage to the fetus

Question 44

How is a cell culture for a virus created?

Answer 44

A slice of tissue is exposed to enzymes which break the cells apart so they are separated The cells are then suspended in the solution called a culture broth with nutrients to keep them alive

Question 45

How do you tell normal cells versus Cells infected with the virus in a cell culture

Answer 45

Normal cells adhere to the glass Viral infection causes the layer to degenerate and tear off the glass

Question 46

What are cytopathic effects?

Answer 46

Changes that occur from a viral infection

Question 47

When was the first virus link to cancer

Answer 47

1908

Question 48

What is a sarcoma

Answer 48

Cancer of connective tissue

Question 49

What is a adenocarcinoma?

Answer 49

Cancer of glandular epithelium meaning the glands

Question 50

What are three reasons why we may not think that viruses cause cancer?

Answer 50

Because they can lay latent Because they have a long incubation time after infection Because we think of cancer as not being contagious but viral diseases are

Question 51

What are oncogenes in viruses?

Answer 51

Cancer inducing genes in viruses

Question 52

What are mutagenic factors?

Answer 52

Factors that activate cancer-causing genes or oncogenes

Question 53

What is an oncogenic virus capable of stimulating?

Answer 53

Tumor production

Question 54

What percent of all cancers are caused by viruses as of right now?

Answer 54

10%

Question 55

What is transformation with regards to viruses and cancer

Answer 55

Tumor cells develop traits distinct from uninfected cells The virally infected cells develop new characteristics due to the viral infection and nothing else

Question 56

What are two examples of transformation that can occur?

Answer 56

Different shapes DNA abnormalities such as damage to the cell membrane

Question 57

Define latent

Answer 57

Dormant

Question 58

Define persistent or chronic

Answer 58

Something that develops slowly over a long period of time

Question 59

How many and what type of diseases do prions cause?

Answer 59

Nine known diseases All of them neurological

Question 60

What does prion stand for?

Answer 60

Proteinaceous infectious particle

Question 61

Why are plant viruses important and what are some of the signs?

Answer 61

They can hurt our economy Some signs are they are discolored won't grow or have stunted growth or wilting

Question 62

What are plant viruses cultivated in And how are they altered to allow the viruses to grow?

Answer 62

Protoplasts And spheroplasts where the cell walls are partially or completely removed

Question 63

What is a viroid and what type of living thing does it infect

Answer 63

It is a chain of RNA and it is only a plant pathogen