30 - Antiviral Medications

Question 1

Viruses are (blank) parasites

Answer 1

obligate intracellular parasites, meaning they rely on host biosynthetic machinery to reproduce

Question 2

When not inside an infected cell, viruses exist as independent particles called

Answer 2

virions

Question 3

Virions consist of:

Answer 3

double or single stranded DNA or RNA

a protein coat (capsid)

some also possess a lipid envelope derived from the host cell, which, like the capsid, may contain antigenic glycoproteins

Question 4

What is viral range?

Answer 4

group of cell types that a virus can infect

Question 5

A virus that infects only bacteria is called

Answer 5

bacteriophage

Question 6

Viruses can be classified based on the shape of their capsid. These shapes include (3)

Answer 6

Helical viruses

Icosahedral viruses

Complex viruses

Question 7

What is latency?

Answer 7

Some viruses can remain dormant in organisms

Question 8

Degree of pathogenicity is called

Answer 8

Virulence

Question 9

Ability of viruses to cause disease is called

Answer 9

pathogenicity

Question 10

The life cycle of viral replication includes:

Answer 10

absorption, penetration, replication,
release

Question 11

DNA replication and transcription

Answer 11

occur in the nucleus

Question 12

Protein translation (mRNA -> protein) occurs in

Answer 12

cytoplasm

Question 13

Viral DNA is often integrated into the host genome and transcribed into mRNA by:

Answer 13

host DNA-dependent RNA polymerase (pox virus is an exception)

Question 14

Viral genome replication requires

Answer 14

DNA-dependent DNA polymerase

Question 15

Double stranded RNA viruses require

Answer 15

RNA-dependent RNA polymerases

so viruses must make itself

DNA NUCLEOUS RNA CYTOPLASM

Question 16

The virus RNA-dependent RNA polymerase acts both as a (blank) to transcribe mRNA and a (blank) to replicate the viral genome

Answer 16

transcriptase

replicase

Question 17

What do retroviruses have?

Answer 17

RNA genome that directs the formation of a DNA molecule (RNA -> DNA -> mRNA -> protein)

Question 18

What enzyme copies viral RNA into DNA?

Answer 18

reverse transcriptase

Question 19

Anti-viral drugs are (blank)

Answer 19

virustatin - only active against replicating viruses and do not affect latent virus

Question 20

Acyclovir is an anti-herpes drug. What is it composed of?

Answer 20

nucleoside analog (fake DNA binding block) which viruses incorporate into their genomes during replication

lacks a hydroxyl group important for forming the backbone of the DNA molecules (DNA chain termination)

the life cycle of the virus is halted because the newly synthesized DNA is inactive

Question 21

The first phosphate group is added by the herpes simplex virus called (blank) which has an affinity for acyclovir that is about 200 time that of the mammalian enzyme

Answer 21

thymidine kinase

Question 22

Acyclovir resistance in herpes simplex virus can result from:

Answer 22

impaired production of viral thymidine kinase

altered thymidine kinase substrate specificity

altered viral DNA polymerase

Question 23

What is HIV

Answer 23

human immunodeficiency virus (HIV) is a lentivirus, a family of retroviruses that lead to chronic persistent infection with gradual onset of clinical symptoms

Question 24

What does HIV infect?

Answer 24

human immune cells (CD4+ T cells)

When CD4+T cells decline below a critical level, cell mediated immunity is lost and the body becomes susceptible to opportunistic infections (AIDS)

replication is constant following infection

Question 25

Anti-viral HIV drugs target viral infection at (blank) levels

Answer 25

multiple (fusion, transcription, integration into host genome, and virion release)

Question 26

Highly active antiretroviral therapy (HAART) involving drug combinations can:

Answer 26

slow or reverse the increases in viral RNA load that normally accompany progression of disease

Question 27

HIV infection begins with attachment of HIV envelope proteins called (blank) to CD4 and CCR5 receptors on surfaces of T cells

Answer 27

gp120

Question 28

Maraviroc is:

Answer 28

CCR5 receptor antagonist (interferes with HIV binding to T cell)

Question 29

HIV reverse transcriptase enzyme synthesizes:

Answer 29

DNA from HIV RNA using nucleosides in the host T-cell

Question 30

What are nucleoside reverse transcriptase inhibitors (NRTI)?

Answer 30

small molecule drugs that are similar to the host cell nucleosides, and are incorporated into new HIV DNA chain as if they were endogenous nucleoside

Question 31

Because NRTIs lack a (blank) attachment of the next nucleoside is impossible. This is called (blank)

Answer 31

3' hydroxyl group on the ribose ring chain termination

Question 32

What is Raltegravir?

Answer 32

antiviral medication used to treat HIV Inhibits integrase

Question 33

What is integrase? What do integrase inhibitors block?

Answer 33

Viral enzyme that inserts viral genome into the DNA of the host cell block the action of integrase to inhibit HIV proliferation

Question 34

Assembly of infectious HIV virions is dependent on (blank). This viral enzyme cleaves precursor proteins to form the final structural proteins of the mature virion core

Answer 34

aspartate proteases

Question 35

What is amantadine

Answer 35

Medication with antiviral and dopaminergic properties It inhibits an early step in replication of the influenza A virus M2 protein functions as a proton ion channel required at the onset of infection to permit acidification of the virus core, which in turn activates viral RNA transcriptase Amantadine blocks proton transfer through M2, thus blocking acidification and the initiation of viral transcription

Question 36

Amantadine is prophylactive against (blank) virus infection and can reduce duration of symptoms if given within 48 hours after contact

Answer 36

influenza A not B

Question 37

What is zanamivir?

Answer 37

inhibitor of neuraminidases produced by influenza A and B These enzymes cleave sialic acid residues from viral proteins that enables virus to be released from the host cell By interfering with these actions, neuraminidase inhibitors impede viral spread

Question 38

Pathogenicity

Answer 38

virus ability to cause disease

Question 39

Virulence

Answer 39

degree of infection