Characterizing and Classifying Viruses, Viroids, and Prions

Question 1

describe polyhedral morphology

Answer 1

D20 dice

Question 2

Describe nucleic acid for viruses

Answer 2

DNA or RNA

Question 3

What is the name for viruses that infect bacteria?

Answer 3

bacteriophage

Question 4

Distinguish between a segmented genome and a genome that has only a single nucleic acid molecule.

Answer 4

single strand in line or in circle
segmented in separate pieces in their own capsule, allows for a lot of mutation

Question 5

define envelope

Answer 5

A covering of lipids, carbs, and protiens. Sometimes comes from the host cell’s cell membrane

Question 6

What are latent infections?

Answer 6

viruses that lie dormant in the body. Can become integrated in host chromosome as a “provirus” (HIV)
non integrated-chickenpox and herpes

Question 7

Name the viruses given in class that are associated with human cancers.

Answer 7

HPV, hep B, Epstein Barr, Human Herpes Virus 8

Question 8

What determines that host range for a virus?

Answer 8

receptors on the host cells that the virus can interact with

Question 9

Define prion.

Answer 9

infectious proteins

Question 10

Describe the lysogenic cycle of bacteriophage lambda.

Answer 10

bacteriophage injects DNA in bacteria, DNA is integrated into bacteria and proliferates. Can move to lytic cycle due to UV light or stress. Prophage is the name for integrated DNA

Question 11

What is another name for viral particles?

Answer 11

virions

Question 12

describe enveloped morphology

Answer 12

has an envelope

Question 13

Describe the following methods used to cultivate animal viruses.
a. embryonated eggs
b. tissue culture
c. plaque assay (what is a plaque?)

Answer 13

A. injected into the membrane of the eggs to use the cells present
B. tissue broken down into cells into a single layer and virus is added
C. plaques show where viruses have destroyed the cells. Corresponds to single virion in mixture.

Question 14

What special enzyme do retroviruses carry with them and what does it do?

Answer 14

reverse transcriptase, convert their RNA to DNA

Question 15

Define viroid.

Answer 15

made of RNA in a free solution

Question 16

define capsid

Answer 16

protein coat that covers the nucleic acids

Question 17

Describe how animal viruses are classified.

Answer 17

genome structure
morphology
envelope or no
body system they affect
taxonomy

Question 18

define nucleocapsid

Answer 18

combo of the genetic material and the capsid, sometimes intertwined

Question 19

describe complex morphology

Answer 19

classic virus with tail fibers and base plate

Question 20

Distinguish between benign and malignant tumors.

Answer 20

benign- abnormal growith in a localized region
malignant- abnormal growth that damages tissues and has the potential to metatisize.

Question 21

What diseases are caused by prions?

Answer 21

mad cow disease, scrapies, variant creutzfeldt-jakob disease, chronic wasting disease in deer and elk

Question 22

Name some characteristics that viruses, prions, and viroids share. How are they different?

Answer 22

acellular
RNA or DNA
obligate intracellular parasites
lots of reasons different

Question 23

describe helical morphology

Answer 23

nucleic acid encapsulated by capsid that resembles a compressed helix, long rod shape.

Question 24

How does the multiplication of animal viruses differ from the multiplication of bacteriophages? How is it the same?

Answer 24

Entry can be DNA insertion (naked viruses only), membrane fusion (envelope virus), endocytosis.

Uncoating of virus protein capsule if entire virus enters the cell

transcription can vary based on RNA or DNA, reverse transcriptase

Assembly is less complex

animal viruses do not lyse cells, they take over the cell metabolism and cell components die.

Question 25

What type of organisms are infected by viroids agents?

Answer 25

plants

Question 26

Describe penetration in the lytic cycle for T-even bacteriophages

Answer 26

phage injects its nucleic acids into the bacteria

Question 27

describe maturation/assembly in the lytic cycle for T-even bacteriophages

Answer 27

creation of mature viruses inside cell

Question 28

Describe attachement in the lytic cycle for T-even bacteriophages

Answer 28

Only happens in host range organisms and connect via H bonds with tail fibers

Question 29

What is unique about the cultivation of bacteriophage?

Answer 29

it's easier than animal virues.

Question 30

What causes hemagglutination?

Answer 30

spike proteins

Question 31

How are prions infectious?

Answer 31

bind to healthy proteins and convert it to an infectious version

Question 32

define spikes

Answer 32

projections from the envelope that may or may not be present. used for attachment to the host

Question 33

List five ways in which viruses are different that other infectious agents.

Answer 33

acellular have DNA or RNA obligate intracellular parasites have host range have protein coating over nucleic acids

Question 34

Do segmented viruses have a single nucleic acid molecule?

Answer 34

no they have multiple

Question 35

describe biosynthesis in the lytic cycle for T-even bacteriophages

Answer 35

viral nucleic acid is replicated and produces proteins needed for virus creation

Question 36

describe release in the lytic cycle for T-even bacteriophages

Answer 36

viruses burst from cells because of sheer number or secretion of lysozyme