13. Characterizing And Classifying Viruses, Viroids, And Prions

Question 0

Virus: extracellular state

___,___,___

Answer 0

Virion
Capsid
Envelope

Question 1

Virus

Answer 1

Minuscule, acellular, infectious agent usually having one or several pieces of nucleic acid (either DNA or RNA)

Question 2

Virus: intracellular state

Answer 2

Capsid removes

Virus exists as nucleic acid

Question 3

Virion

Answer 3

A virus when outside a cell

Question 4

Capsid

Answer 4

Protein coat surrounding a nucleic a core

Question 5

Envelope

Answer 5

Phospholipid membrane that surrounds the capsid of some virions

Question 6

Genetic material of viruses

Answer 6

Primary way scientists categorize and classify viruses

dsDNA, ssDNA, dsRNA, ssRNA

Question 7

How can viruses be specific for a host cell

Answer 7

Due to affinity of viral surface proteins for complementary proteins on host cell surface

Question 8

Structure & function of capsid

Answer 8

Composed of proteinaceous subunits called capsomeres.

Provide protection for viral nucleic acid

Question 9

Structure & function of viral envelope

Answer 9

All viruses lack cell membranes

Play role in host recognition

Question 10

Characteristics used to classify viruses

Answer 10

Type of nucleic acid
Presence/absence of envelope
Shape
Size
Relationship between viruses 
Named for special characteristics

Question 11

Lytic replication in bacteriophages

Answer 11

Viral replication usually results in death and lysis of host cell
-attachment, entry, synthesis, assembly, release

Question 12

Lysogeny

Answer 12

Modified replication cycle in which infected host cell grow and reproduce normally for many generations before they lyse

Question 13

Bacteriophage replication

Answer 13

Lytic, lysogenic

Question 14

Animal virus replication differs from bacteriophages because…

Answer 14

Presence of envelopes around some of the viruses

Question 15

3 mechanisms of entry of animal viruses

Answer 15

Direct penetration
Membrane fusion
Endocytosis

Question 16

Budding in animal viruses

Answer 16

Viral release where virions are extruded from host cell and acquire a portion of membrane which becomes viral envelope

Question 17

Latency of animal viruses

Answer 17

When animal viruses remain dormant in in host cells

Question 18

Neoplasia

Answer 18

Uncontrolled cell division in multicellular animal

Question 19

Tumor

Answer 19

Mass of neoplastic cells

Question 20

Malignant

Answer 20

Cancers: invade other tissues

Question 21

Metastasis

Answer 21

Process of tumors spreading

Question 22

Benign

Answer 22

Remain in one place, lass harmful

Question 23

Viruses cause 20-25% of human cancers. T/F?

Answer 23

True

Question 24

3 ways of culturing viruses

Answer 24

Media consisting of mature organisms Embryonated eggs Cell cultures

Question 25

Problems with culturing viruses

Answer 25

Have to grow in living animals or cells, ethical problems with housing animals, expensive to house animals, some viruses only infect humans and difficult to grow

Question 26

Viroids

Answer 26

Extremely small circular pieces of RNA that are infectious and pathogenic in plants (Not viruses because lack capsids) ONLY IN PLANTS

Question 27

Prions

Answer 27

Proteinaceous infective particles Do not contain nucleic acids like viruses Very different type of infection

Question 28

Diseases caused by prions

Answer 28

``` Creutzfeldt-Jakob Mad cow Chronic wasting disease Scrapie Kuru ```