Exam 1 - Ch. 13 - Characterizing and Classifying Prions

Question 1

What causes the diseases that plague most of the industrial world?

Answer 1

Viruses

Question 2

What are some of the characteristics of viruses?

Answer 2

Miniscule, acellular, it either has DNA or RNA but never both.

Question 3

What does acellular mean?

Answer 3

No processes of life

Question 4

A virus in its extracellular state is called what?

Answer 4

A virion

Question 5

What does a virion look like?

Answer 5

Protein coat surrounding a nucleic acid core.

Question 6

What is the protein coat of a virion called?

Answer 6

capsid

Question 7

What is the outer structure of phospholipids that encloses the nucleocapsids of some viruses called?

Answer 7

envelope

Question 8

What does the capsid and/or envelope do for the virion?

Answer 8

Provides protection for the viral nucleic acid and means of attachment to host’s cells

Question 9

What happens to the virus once it is inside the host cell?

Answer 9

The capsid is removed and it simply exists as a nucleic acid.

Question 10

What is it called when the virus removes its capsid?

Answer 10

uncoating

Question 11

Viruses can be _____ or _____.

Answer 11

Specific or generalists

Question 12

Most viruses are ____.

Answer 12

Specific, only attack particular host cells

Question 13

What types of organisms are susceptible to a viral attack?

Answer 13

All types

Question 14

What are the 3 viral shapes?

Answer 14

Complex
Helical
polyhedral

Question 15

What viral shape is capsid of many shapes?

Answer 15

complex

Question 16

What type of virus shape is spiral?

Answer 16

helical

Question 17

What type of viral shape is a geodesic dome?

Answer 17

polyhedral

Question 18

What is the most common viral shape?

Answer 18

polyhedral

Question 19

What virus is famous for it’s bullet shaped capsid?

Answer 19

Rabies

Question 20

What shape is the bacteriophage?

Answer 20

complex

Question 21

3 Functions of the viral envelope.

Answer 21

Provides protection
Plays a role in host recognition.
Helps viruses enter hosts cells.

Question 22

A virus that has an envelope is called?

Answer 22

Enveloped virion

Question 23

A virus with no envelope is called?

Answer 23

Non-enveloped/naked virion

Question 24

The projections of viral glycoproteins on the envelope are called?

Answer 24

spikes

Question 25

Where does the viral envelope come from?

Answer 25

Acquired from host cell during viral replication or release.

Question 26

4 ways viruses are classified?

Answer 26

Type of nucleic acid, Presence of an envelope, Shape, size

Question 27

How are viruses named?

Answer 27

name of disease + virus

Question 28

What is special about viral replication?

Answer 28

They are dependent of hosts' organelles and enzymes to produce new virion.

Question 29

What viral replication cycle results in death and lysis of host cell?

Answer 29

Lytic replication

Question 30

What are the five stages of Lytic replication of a virus.

Answer 30

``` Attachment of virus to host. Entry into host. Synthesis of new nucleic acids. Assembly of new virions. Release of new virions. ```

Question 31

Modified viral replication cycle where infected host cells grow and reproduce normally for generations before the lyse.

Answer 31

Lysogeny

Question 32

What are temperate phage?

Answer 32

Inactive "hanging out - house guest"

Question 33

What are prophages?

Answer 33

Inactive phages.

Question 34

When phages carry genes that alter phenotype of a bacterium, it is called? (viral chromosome incorporates into host's cell.)

Answer 34

lysogenic conversion.

Question 35

Viral replication of animal viruses is same as basic replication as bacteriophages but there are some differences. (3)

Answer 35

Presence of envelope around some (a lot have). Eukaryotic nature of animal cells. Lack of cell wall in animal cells.

Question 36

Attachment of animal viruses is by what?

Answer 36

Chemical attraction

Question 37

Animal viruses do not have tails or tail fibers like bacteriophages, but the doe have what that helps them attach to host?

Answer 37

Glycoprotein spikes or other attachment molecules.

Question 38

3 mechanisms of entry of animal viruses?

Answer 38

Direct penetration Membrane fusion endocytosis

Question 39

Which mechanism of entry is the easiest?

Answer 39

Direct penetration

Question 40

What happens that is different in membrane fusion of virus?

Answer 40

Viral glycoprotein remain in cytoplasmic membrane.

Question 41

What is different about the process of budding in enveloped viruses?

Answer 41

It doesn't kill the cell.

Question 42

What is the process of budding in Enveloped viruses?

Answer 42

Virus obtains capsid and picks up glycoprotein on cell surface and buds of leaving host cell.

Question 43

When animal viruses remain dormant in host cells it is called?

Answer 43

Latent viruses or proviruses

Question 44

Is incorporation of previous into host DNA permanent?

Answer 44

YES

Question 45

What is the most common and inexpensive way to culture viruses in the laboratory?

Answer 45

In embryonated chicken eggs.

Question 46

What are other ways to culture viruses in lab?

Answer 46

In mature organisms (like bacteria, plants, and animals) and in cell (tissue) culture- cells isolated and grown on medium with a broth.

Question 47

What are proteinaceous infectious agents that lack a nucleic acid called?

Answer 47

prions

Question 48

Are prions easy to destroy?

Answer 48

No, they are very, very difficult to destroy!

Question 49

What are the ways to destroy prions?

Answer 49

Incineration and autoclaving in sodium hydroxide

Question 50

How does a prion cause disease?

Answer 50

Prion PrP converts cellular PrP into Prion PrP by inducing conformation change.

Question 51

What is the disease-causing form of Prion Pro?

Answer 51

B-Sheets (beta)

Question 52

What is normal form of cellular PrP?

Answer 52

a-helices (alpha)

Question 53

Where is the prion disease expression most predominant?

Answer 53

In the nervous system.

Question 54

What is the characteristic of the brain with a prion disease?

Answer 54

Large vacuoles form in brain - characteristic spongy appearance.

Question 55

What are 3 prion diseases that cause spongiform encephalopathies?

Answer 55

BSE - mad cow's disease vCJD - humans get from eating cows with disease Kuru