chapter 5 objectives

Question 1

what does it mean to be filterable

Answer 1

they are smaller than bacteria and able to pass through filter designed to trap bacteria

Question 2

size of virus compared to microorganisms

Answer 2

20nm up to 1000nm

Question 3

6 characteristics of virus

Answer 3

10x number of bacteria/archae, ubiquitous, protein shell surrounds nucleic acid core, DNA or RNA (not both), high specificity/tropism, multiplication

Question 4

tropism

Answer 4

high specificity

Question 5

4 ways viruses are named

Answer 5

hosts and diseases they cause
structure
chemical composition
genetics

Question 6

3 methods to grow viruses

Answer 6

Egg culture
Cell culture
Animal inoculation

Question 7

2 types of viral capsids

Answer 7

made of a protein subunits called capsomeres
helical viruses and and icosahedral viruses

Question 8

enveloped vs naked viruses

Answer 8

enveloped: surrounded by an envelope and nucleocapsid
naked: only composed of nucleocapsid

Question 9

importance of viral surface proteins

Answer 9

pikes help a virus attach and penetrate into its host cell

Question 10

types of nucleic acids viruses contain

Answer 10

DNA: single-stranded or double stranded
RNA: can be double stranded, but usually single stranded
+ RNA, -RNA

Question 11

virion

Answer 11

fully developed viral particle

Question 12

5 step life cycle of viruses

Answer 12

adsorption, penetration/uncoating, synthesis, assembly, release

Question 13

adsorption

Answer 13

invasion of a cell with virus

Question 14

penetration/uncoating

Answer 14

cell membrane penetrated by whole virus through endocytosis/direct fusion

Question 15

endocytosis

Answer 15

entire. virus engulfed by cell

Question 16

direct fusion processes

Answer 16

envelope merges directly with cell membrane

Question 17

synthesis

Answer 17

replication and protein production
DNA–>nucleus
RNA–>cytoplasm

Question 18

assembly

Answer 18

put together parts manufacture during synthesis process

Question 19

release

Answer 19

the number of viruses released by infected cell

Question 20

cytopathic effect

Answer 20

virus-induced damage to the cell that alters its microscopic appearance, ex. inclusion bodies (compacted viruses)

Question 21

acute infection

Answer 21

sudden onset of a disease and can also be resolved rather quickly

Question 22

persistent infection

Answer 22

latent or chronic;
latent:cell harbors the virus and is not immediately lysed
chronic: virus remains and multiplies at low low levels

Question 23

transforming infection

Answer 23

characterized by increased rate of growth and changes in chromosomes or cell’s surface

Question 24

oncogenic virus

Answer 24

cancer-causing virus
ex. hepatitis B virus

Question 25

5 stages of t-even bacteriophage replication

Answer 25

adsorption: binding bacteriophage to host cell
injection of phage DNA
synthesis of phage
assembly
release

Question 26

lysogenic cycle

Answer 26

condition which the host chromosome carries bacteriophage

Question 27

lytic cycle

Answer 27

cells lyse to release new viruses

Question 28

lysogenic conversion

Answer 28

when bacterium acquires a new trait from its template phage

Question 29

3 noncellular infectious agents

Answer 29

prions, satellite viruses, viroid

Question 30

prion vs virus/bacteria

Answer 30

prions not containing nucleic acids and are made entirely of misfolded proteins

Question 31

reason why antiviral drugs are more difficult to design than antibacterial drugs

Answer 31

replication of viruses, rapid genetic variability, lack of specific viral targets, complexity of viral life cycle