Ch 13 (Viruses, Viroids, and Prions)

Question 1

What are the characteristics of viruses?

Answer 1

Small, acellular, infectious, DNA or RNA

Question 2

What do viruses depend on the host for?

Answer 2

Metabolic pathway & reproduction/replication

Question 3

What happens if the virus is in the environment?

Answer 3

No growth or response

Question 4

What is a virion?

Answer 4

Extracellular state. Has nucleocapsid, phospholipid envelope.

Question 5

What is the nucleocapsid made of?

Answer 5

Protein (capsid) and nucleic acid

Question 6

True or False. Viruses have both DNA and RNA.

Answer 6

False.

Question 7

True or False. Viruses infect specific host cells and why? Example?

Answer 7

True, due to complimentary proteins. Ex: HIV and T cells

Question 8

What are generalist viruses? Example?

Answer 8

Infect many cells. Ex: West Nile Virus

Question 9

What is capsid made of

Answer 9

Capsomeres (protein subunit)

Question 10

What is the viral envelope made of?

Answer 10

Phospholipid bilayer and proteins.

Question 11

What are glycoproteins in the envelope used for?

Answer 11

Attach to host cell & host recognition

Question 12

Which viruses are more fragile, enveloped or naked?

Answer 12

Enveloped due to phospholipid bilayer

Question 13

What is an example of an enveloped virus? Non enveloped?

Answer 13

Envelope is flu and non enveloped is cold

Question 14

True or false, a cold is more severe than the flu.

Answer 14

False. Enveloped viruses are more severe

Question 15

What are the five steps of lytic replication.

Answer 15

Attachment, entry, synthesis, assembly, and release.

Question 16

Explain the steps of lytic replication (Attachment)

Answer 16

viral protein bind w/ host cell receptor

Question 17

Explain the steps of lytic replication (Entry)

Answer 17

Lysozyme break cell wall. Nucleic acids and enzymes enter.

Question 18

Explain the steps of lytic replication (Synthesis)

Answer 18

Enzyme degrade host chromosome, hijack host cell enzymes. Viral particle synthesis.

Question 19

Explain the steps of lytic replication (Assembly)

Answer 19

Viral particle assembly

Question 20

Explain the steps of lytic replication (Release)

Answer 20

Viral particle release, host cell is lysed (die)

Question 21

What is lysogeny in bacteriophage?

Answer 21

Reproduction where virus is dormant and integrate into bacterial chromosome

Question 22

What are the steps of lysogeny?

Answer 22

Attach, entry, integrate, cell division, and induction

Question 23

What’s the difference between the lytic cycle and lysogeny?

Answer 23

Lytic cycle = dead host; lysogeny = living host

Question 24

True or false, lysogeny is a continuation of the lytic cycle.

Answer 24

True

Question 25

True or false, if the virus is induced during lysogeny, it continues the lytic cycle.

Answer 25

True

Question 26

How do animal viruses attach?

Answer 26

Glycoproteins & chemical attraction

Question 27

What is chemical attraction in animal viruses

Answer 27

Viral protein bind w/ cell receptor

Question 28

How do viruses infect cells?

Answer 28

Uncoat and release nucleic acid in cell

Question 29

What are the 3 mechanisms of entry for animal viruses and describe them.

Answer 29

Direct penetration, membrane fusion, and endocytosis

Question 30

How are enveloped animal viruses released?

Answer 30

Budding

Question 31

How are naked animal viruses released?

Answer 31

Exocytosis or lysis

Question 32

What is a retrovirus?

Answer 32

Has reverse transcriptase, RNA virus

Question 33

What is a prophage?

Answer 33

inactive bacteriophage (during integration)

Question 34

What is lyosgenic conversion?

Answer 34

Phage change phenotype of bacterium

Question 35

What are proviruses?

Answer 35

Latent/dormant animal virus

Question 36

T/F Proviruses can go through induction.

Answer 36

False, incorporation is permanent

Question 37

What is neoplasia?

Answer 37

Unctrolled cell division

Question 38

What is a the difference between benign and malignant tumor

Answer 38

Can't spread vs Can Spread

Question 39

What is metastasis?

Answer 39

Tumor travels and invades throughout body

Question 40

What is the oncogene theory

Answer 40

Protoocogene is off and repressor is on until virus is inserted (changes promoter to oncogene and causes uncontrolled cell division)

Question 41

What is the 2 hit theory

Answer 41

How viruses might cause cancer (activate protooncogene and damage receptor protein)

Question 42

What does the protooncogene do?

Answer 42

Promote cell growth and division

Question 43

What does the oncogene do (Hint zombie)

Answer 43

Makes cells that should be dead to come to proliferate

Question 44

How are viruses cultured in the lab?

Answer 44

Organisms (bacteria, plants, animals), chicken egg, & cell tissue

Question 45

What are viroids

Answer 45

Small ssRNA, infects plants, no caspid

Question 46

What happens when a viroid infects a plant?

Answer 46

Prevents translation (no protein), plant enzymes degrade dsRNA

Question 47

What are prions

Answer 47

Protein viruses. NO NUCLEID ACID

Question 48

What is cellular PrP protein

Answer 48

normal, alpha helices

Question 49

What is a prion PrP

Answer 49

Disease causing, beta-sheet

Question 50

What happens if cellular PrP interacts w/ prion pRp

Answer 50

Cellular PrP misfolds & changes to priont PrP

Question 51

What are the 3 spongiform encephalopathies?

Answer 51

BSE (Bovine spongiform encephalitis), vCJD (variant Creutzfeldt-Jakob disease), Scrapie

Question 52

How are prions treated?

Answer 52

incineration, autoclave, prionenzyme