Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PMCOL 200 > Antivirals > Flashcards

Antivirals Flashcards

1
Q

What are viruses?

A

Obligate intracellular parasites (rely on a host cell to reproduce)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do viruses exist outside on infected cell?

A

Virions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How many proteins can viruses encode?

A

~4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do virions consist of? (3)

A

dsDNA or ssDNA, lipid envelope (from host cell) and protein coat/capsid (both can contain antigenic glycoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How big are virions approx?

A

1/100 of a bacterium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the viral range?

A

Group of cell types/species that virus can infect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a virus that only infects bacteria?

A

Bacteriophage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are viruses that infect plants and animals?

A

Plant viruses and animal viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Can animal viruses infect other (cross) phyla?

A

No, but may affect closely related species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How are viruses classified? Diff categories?

A

Shape of capsid; helical, icosahedral, complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is pathogenicity?

A

Ability of viruses to cause disease (not all cause disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is virulence?

A

Degree of pathogenicity (intensity of disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is virus latency?

A

Ability to remain dormant in an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the virus that causes chicken pox and shingles?

A

Varicella zoster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does chicken pox exhibit latency?

A

Can remain dormant in body and remerge later in life as shingles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are people chronically infected and serve as reservoirs of infectious virus?

A

Carrriers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are 4 stages of virus life cycle?

A

Absorption, penetration, replication, release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What determines virus range and initiation of infection process?

A

Proteins on surface of virus (antigen) that bind to protein receptors in host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What occurs once virus has access to host cytoplasm?

A

Viral DNA or RNA crosses pmemb to to cytoplasm or nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What occurs to viral DNA or RNA once inside host cell?

A

Interacts w/ host machinery to translate DNA/RNA into viral proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the 4th stage of a viral life cycle (release)?

A

Newly synthesized virion particles are release to continue infection cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 2 types of viruses?

A

RNA or DNA viruses, can be double stranded or single stranded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How does a DNA virus transcribe and translate its specific proteins in a host?

A

Viral DNA incorporates genome w/ host’s (in nucleus) and is transcribed into mRNA w/ host DNA-dependent RNA polymerase, mRNA in translated into viral proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Are DNA viruses usually ds or ss?

A

Double stranded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are poxviruses able to do?

A

Can replicate in hosts cytoplasm as they carry their own DNA-dependent RNA pol (are a DNA virus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is required for viral genome REPLICATION?

A

DNA-dependent DNA pol (from host)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How does a RNA virus transcribe and translate its specific proteins in a host?

A

Require an RNA-depended RNA pol (RNA -> mRNA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the 2 purposes of RNA-dependant RNA pol?

A

Transcriptase (transcribe mRNA) and replicase (replication)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Where do most RNA viruses complete their replication? Exception?

A

Host cell cytoplasm; influenza in nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are retroviruses?

A

Viruses that have RNA genome (ss) that directs DNA formation from RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is reverse transcriptase?

A

Viral enzyme that turns viral RNA into DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is reverse transcriptase aka?

A

RNA-dependent DNA pol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What occurs to viral DNA from a retrovirus?

A

Is integrated w. Host DNA and transcribed in mRNA and translated into proteins (by host enzymes)

34
Q

T/f: most retroviruses immediately kill their host cells

A

False, infected host cells can continue to replicate w/ proviral DNA

35
Q

What is an ex of a retrovirus?

A

HIV

36
Q

What is the best/cheapest/effective what to prevent viral infections?

A

Vaccinations

37
Q

Approx. how many infections are their vaccines for?

A

13 (14 w/ COVID?)

38
Q

What can vaccines contain? (4)

A

Live-attenuated (cant replicate) or killed viruses, viral proteins or mRNA (antigens)

39
Q

How do vaccines work?

A

Cause host to generate antibodies for virus to decr response to 2nd infection

40
Q

How do antiviral drugs work?

A

Exert actions at several stages of viral life cycle (treat after infection)

41
Q

What are 5 targets of antiviral drugs?

A

Stages of viral life cycle: viral entry, nucleus acid synthesis, protein synthesis, viral packaging, and virion release

42
Q

What can antiviral combination therapy allow for?

A

Incr clinical effectiveness and prevent/delay resistance

43
Q

What does “anti-viral drugs are virustatic” mean?

A

Only work against replicating viruses (not latent/dormant)

44
Q

What is acyclovir?

A

Anti-herpes drug that is a nucleoside analog (fake DNA building block) which viruses incorporate into genome during repl’n

45
Q

How does acyclovir cause DNA chain termination?

A

Lacks an -OH group that is needed for chain elongation of the DNA backbone

46
Q

What is the result of acyclovir causing chain termination?

A

The virus life cycle is halted since newly synthesized DNA is inactivated

47
Q

Why does acyclovir only affect viral DNA if humans also rely on guanine (its NT analog)?

A

Herpes thymidine kinase has affinity 200x greater for acyclovir vs mammalian thymidine kinase (specificity)

48
Q

What must occur to acyclovir before it can be incorporated into viral DNA?

A

Phosphorylated into acyclovir-triphosphate, herpes thymidine kinase adds first phosphate group (host has own thymidine kinase)

49
Q

What 3 ways can herpes simplex virus have acyclovir resistance?

A

Impaired viral thymidine kinase production (decr acyclovir phos’n and DNA incorp.), altered thymidine kinase substrate specificity (phos’n of thymidine vs acyclovir), altered viral DNA pol (integrates normal NT vs acyclovir)

50
Q

What is HIV?

A

Human immunodeficiency virus; a retrovirus (lentivirus) that causes chronic/persistent infection w/ gradual onset symptoms

51
Q

Which cells and receptors does HIV infect?

A

T cells; CD4+

52
Q

What occurs when CD4+ T cell levels decline below a critical level after HIV infection?

A

Host loses cell-mediated immunity and is susceptible to opportunistic infections (AIDS)

53
Q

T/f: there is a period of viral latency after HIV infection

A

False, repl’n is constant after infection (wo/ treatment)

54
Q

T/f: anti-viral HIV drugs only target one step of viral life cycle

A

False, drugs can target multiple levels (fusion, transcription, integration, viral release)

55
Q

Currently, how many antiretroviral drugs are used to treat HIV?

A

Usually 3 or more together

56
Q

What is highly active retroviral therapy (HAART)?

A

Drug combinations that can slow/reverse viral RNA production (HIV disease progression)

57
Q

What occurs at the beginning of HIV infection?

A

Gp120 (HIV envelope proteins) bind to CD4 and CCR5 receptors on T cells

58
Q

What are entry inhibitors for HIV?

A

Antivirals that interfere w/ binding, fusion, and entry of HIV virion into human call

59
Q

What is maraviroc?

A

CCR5 receptor antagonist that interferes w/ HIV binding to T cell

60
Q

What is reverse transcriptase?

A

HIV enzyme that converts viral RNA into DNA using host nucleosides (RNA dependent RNA pol)

61
Q

What are nucleoside reverse transcriptase inhibitors (NRTIs)?

A

Small molecule drugs that resemble host nucleosides and are incorporated into new HIV DNA (by reverse transcriptase)

62
Q

How do NRTIs cause chain termination?

A

NTRIs lack 3’-OH on ribose ring (prevent elongation)

63
Q

What provides NTRIs w/ viral specificity? (Ie. don’t affect mammalian transcription)

A

Mammalian RNA (DNA to RNA) and DNA pols (DNA to DNA) are distinct enough from viral reverse transcriptase (RNA to DNA)

64
Q

What is integrase?

A

Viral enzyme that inserts viral/HIV DNA into host genome

65
Q

What are integrase strand transfer inhibitors (INSTs)?

A

Block activation of integrase and inhibit viral DNA incorporation into host genome (inhibits HIV proliferation)

66
Q

What is an ex of a INST?

A

Raltegravir

67
Q

What are aspartase proteases?

A

Viral enzymes that are required for assembly of HIV virions (cleave precursor proteins for mature virion core)

68
Q

What are HIV protease inhibitors?

A

Antivirals that bind to and inhibit aspartase proteases (active site ligand analog) that prevents new HIV from becoming mature

69
Q

T/f: HIV protease inhibitors are usually used w/ reverse transcriptase inhibitors

A

True

70
Q

What is amantadine?

A

Anti-influenza drug that inhibits uncoating of influenza A virus (early step in replication)

71
Q

What is the M2 protein?

A

Proton pump that permits acidification of virus core to allow activation of viral RNA transcriptase (onset of infection)

72
Q

How does amantidine affect M2?

A

Blocks proton transfer through M2, blocking acidification and viral transcription

73
Q

T/f: amantidine is prophylactive against influenza A not B

A

True

74
Q

T/f: amantidine and block infection or reduce symptoms of influenza if given w/ 48 hours after contact

A

True

75
Q

What is a resistant influenza A virus mutant?

A

H3N2

76
Q

What is a more cost-effective strategy against influenza?

A

Vaccination

77
Q

What is a possible treatment against influenza in high-risk/immunocompromised patients?

A

Seasonal prophylaxis using anti-viral drugs (if vaccine cant be administered)

78
Q

What is zanamivir?

A

Anti-influenza drug that inhibits neuroaminidases produced by influenza A and B

79
Q

What are neuroaminidases?

A

Enzymes that cleave sialic acid residues from viral proteins that enable virus to be released from host cell

80
Q

How do neuroaminidase inhibitors (zanamivir) provide anti-influenza action?

A

Prevent viral spread (prevent release from host cell by neuroaminidases)

PMCOL 200 (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions