viruses and subviral particles

Question 1

virus genetic information can be …

circular or linear
single or double stranded
DNA or RNA

Answer 1

it can be all of those things!

Question 2

__________ is the protein coat of a virus and may be surrounded by an envelope composed of phospholipids

Answer 2

capsid

Question 3

the envelope is sensitive to what?

Answer 3

heat
detergents
dessication

Question 4

(enveloped / nonenveloped) virsues are easier to kill

Answer 4

enveloped

Question 5

T / F - viruses can reproduce independently

Answer 5

false

Question 6

viruses must express and replicate genetic information within a __________

Answer 6

host cell

Question 7

do viruses have ribosomes?

Answer 7

no

Question 8

___________ are released to infect additional cells after a virus has taken over a host cell

Answer 8

virions

Question 9

bacteriophages specifically target ___________

Answer 9

bacteria

Question 10

how do bacteriophages attack bacteria?

Answer 10

inject their genetic material, leaving the remaining structures outside the infected cell

Question 11

in addition the the capsid, what other structural features does a bacteriophage possess?

Answer 11

tail sheath
tail fibers

Question 12

____________ can act like a syringe, injecting genetic material into a bacteria

Answer 12

tail sheath

Question 13

_____________ help the bateriophage recognize and connect to the correct host cell

Answer 13

tail fibers

Question 14

___________ sense implies that the genome may be directly translated to functional proteins by the ribosomes of the host cell (just like mRNA)

Answer 14

positive sense

Question 15

_____________ sense uses an RNA strand that acts as a template for synthesis of a complementary strand, which can then be used as a template for protein synthesis

Answer 15

negative

Question 16

negative sense RNA viruses must contain a ________ in the virion to ensure the complementary strand is synthesized

Answer 16

RNA replicase

Question 17

_____________ are enveloped, single stranded RNA viruses that synthesize DNA from RNA

Answer 17

retroviruses

Question 18

retroviruses must contain a ____________ to ensure the transcription of DNA from RNA

Answer 18

reverse transcriptase

Question 19

what is a common example of a retrovirus?

Answer 19

HIV

Question 20

T / F - without the proper receptors a cell is essentially invisible to a virus

Answer 20

true

Question 21

______________ viruses fuse with the plasma membrane of a cell, allowing entry of the virion into the host cell

Answer 21

enveloped

Question 22

____________ viruses fuse with the membrane and enter the cell intact

Answer 22

enveloped

Question 23

after infection, ____________ of viral genetic material must occur in order for the virus to reproduce

Answer 23

translation

Question 23

________ only insert their genetic mateiral into the cell, leaving their capsid outside the host cell

Answer 23

bacteriophages

Question 24

most DNA viruses must enter the _____________ in order to be transcribed into mRNA

Answer 24

nucleus

Question 25

___________ viruses stay in the cytoplasm wgere it is directly translated into proteins by host cell ribosomes

Answer 25

positive sense RNA viruses

Question 26

___________ viruses require synthesis of a complementary RNA strand (via RNA replicase) which can then be translated to form proteins

Answer 26

negative sense RNA viruses

Question 27

DNA formed through reverse trascription in _____________ travel to the nucleus where it can be integrated into the host genome

Answer 27

retroviruses

Question 28

three types of viral progeny release processes

Answer 28

1. cell death, results in spilling of the viral progeny
2. host cell lyses as a result of being filled with a large number of virions
3. extrusion, virus can leave the cell by fusing with its plasma membrane

Question 29

why is lysing a host cell actuall disadvantagous for a virus?

Answer 29

the virus can longer use the host cell to carry out its life cycle

Question 30

a virus using extrusion, which keeps the host cell alive for continued use is said to be in a ________ cycle

Answer 30

productive

Question 31

___________ cycle is when a bacteriopahge maxmizes the use of the cell’s machinary with little regard for the survival of the host cell

Answer 31

lytic

Question 32

T / F - viruses in the lytic phase are termed virulent

Answer 32

true

Question 33

_____________ cycle is when the virus will be replicated as the bacteria reproduces because it is a part of the host’s genome

Answer 33

lysogenic

Question 34

although a virus may remain integraed into the host genome, what may cause the provirus to leave the genome and revert to a lytic cycle?

Answer 34

environmental factors

radiation
light
chemicals

Question 35

___________ are infectious proteins that cause disease by triggering misfolding of proteins

Answer 35

prions

Question 36

T / F - prions are living things

Answer 36

false

Question 37

what type of misfolding is most commonly caused by prions?

Answer 37

conversion of a protein from a alpha helix to a beta sheet

Question 38

what is the side effects of prion diseases?

Answer 38

insolubility of protein
reduced ability for cell to degrade the protein
protein aggregate forms
interferes with cell functions

Question 39

____________ are small pathogens consisting of a short circular single stranded RNA that infects plants

Answer 39

viroids