Antiviral II

Question 1

T or F: Viruses are intra cellular parasites..

Answer 1

True

Question 2

Do viruses possess both DNA AND RNA ?

Answer 2

No, they have either or.

Question 3

What are the steps for DNA virus replication?

Answer 3

Attachment, entry and uncoating, DNA synthesis via replication, expression of genes(capsid protein), maturation, release.

Question 4

What primary difference is found in retrovirus replication vs dna replication?

Answer 4

RNA VIRUS enters and undergoes dsDNA synthesis with reverse transcriptase sand integrates itself, becomes a provirus.

Question 5

Most of the clinical pharmacological inhibitors are involved in what process of the host cell?

Answer 5

Genome replication and gene expression.

Question 6

What is the main target for inhibition of viral genome replication ?

Answer 6

Viral DNA-dependent DNA polymerase

Viral RNA-dependent RNA polymerase

Viral RNA-dependent DNA polymerase (Reverse Transcriptase)

Question 7

Nucleoside analogs are used to target thymindine kinase and DNA Pol but must be converted from prodrug to its active form . What is the active form ? What converts it ?

Answer 7

Acyclo-guanosine triphosphate.

Thymindine Kinase

Question 8

A poor substrate for human cellular TK and DNA Pol is ?

Answer 8

Acyclovir

Question 9

Thymindine kinase phosphorylates acyclovir because ?

Answer 9

Tk is promiscuous and will phosphorylate anything that is looks like a nucleoside.

Question 10

Review : Slide 11 describes the key features of acyclovir triphosphate which is the effector of inhibition of DNA pol. When incorporated, what occurs to the phosphate and the enzyme

Answer 10

Acyclovir triphosphate becomes monophosphate and changes the conformation of the enzyme , DNA pol.

Question 11

Acyclovir serves as a chain inhibitor because it lacks a 3’ hydroxyl group. What does it also alter ?

Answer 11

It alters the catalytic site of the enzyme, DNA Pol.

Question 12

Resistance is mostly due to mutation in either .
A. TK
B. DNA POL
C.  Both
D. Neither

Answer 12

C. Both

Question 13

Which mechanism is most common?
A. TK deficient mutant
B. TK low producer mutant 
C. Mutant that produces an altered TK. 
D. NEITHER

Answer 13

A. Selection of TK-deficient mutant

Question 14

DNA poly. Resistance is mediated by mutation enhancing the excision of the analog after? (The most common feature)

Answer 14

It has been incorporated into DNA chain

Question 15

Valacyclovir a valine ester has a good oral bioavailability what other two prodrugs have a good oral bioavailability?

Answer 15

Famciclover and Valganciclovir

Question 16

Which acyclovir derivative is most toxic due to its addition of the 3’ CHOH group?

Answer 16

Valganciclovir

Question 17

T or F. Cidofovir is approved for HIV PATIENTS.

Answer 17

True

Question 18

HIV Genome organization includes all the following, which one of them is derived from polyproteins A and B?

LTRs
Phi sequence - packaging of RNA into mature viral particles.
gag- the interior core of the viral particle
Pol- protease
Env

Answer 18

Gag and pol

Question 19

Similar to herpesviruses, What infections does HIV form ?

Answer 19

Latent

Question 20

There are no drugs for latent infections caused by HIV but which target is not actively used by anti-HIV drugs?

A. Viral fusion
B. Reverse transcription
C. Maturation
D. Integration

Answer 20

D. Integration

Question 21

Lamivudine is less toxic than AZT. What does it inhibit!?

Answer 21

HIV and Hepatitis B reverse transcriptase.

Question 22

Emtricitabine inhibits HV RT, WHAT GROUP DISTINGUISHES IT FROM LAMIVUDINE ?

Answer 22

Contains that 5-fluoro-group

Question 23

Reasons why we need to make a cocktail of different drugs? Which is missing?

1. Low efficacy of each drug alone
3. -
4. Multiple resistance mutations decrease the fitness of the virus

Answer 23

2. Mutations conferring resistance to one drug do not confer resistance to others
3. Mutations at the different sites can adversely affect one another

Question 24

Anti-SARS nucleoside analogs cause delay of chain termination, what drugs do so?

Answer 24

Remdesivir and Molnupiravir

Question 25

To inhibit both viral DNA and RNA polymerase this drug does not require the activation of viral or cellular TK What drug is this?

Answer 25

Foscarnet

Question 26

Efavirenz, nevirapine and delavirdine all inhibit

Answer 26

HIV RT.

Question 27

T or F: Nevirapine binds on the backside of RT and changes the shape of the active site, blocking its action and works well with AZT

Answer 27

Yes, it works great with Azidothymidine.

Question 28

The main target of viral maturation is essential in all of these except?
A. Essential for HIV replication
B. Point Mutation inactivates the enzyme
C. Conserved/Odd substrates
D. Unique enzyme
E. The enzyme can be used in large quantity
F. Synergistic relationship

Answer 28

F. Synergetic relationship

Question 29

What is the main target for viral maturation?

Answer 29

HIV protease

Question 30

Ritonavir is an HIV protease inhibitor that affects?

Answer 30

Viral maturation

Question 31

Recall: Ritonavir is going to bind competitively and?

Answer 31

change the active site.

Question 32

Inhibition of viral gene expression involved which protease inhibitors?

Answer 32

HCV(Hepatitis C) NS3 /A4 protease inhibitors.

Question 33

Inhibtion of viral gene expression involved which protease inhibitors?

Answer 33

HCV(Hepatitis C) NS3 /A4 protease inhibitors.

Question 34

The HCV
polyprotein and
anti-HCV protease
inhibitors

Answer 34

Telaprevir, Boceprevir, Simeprevir, and Paritaprevir.

Question 35

Nirmatrelivir inhibits SARS-COVID2, what kind of inhibition is this for antivirals.

Answer 35

Viral gene expression

Question 36

Nirmatrelivir is a

Answer 36

Viral gene expression

Question 37

What are the modes of action for nucleoside analogs? 3

Answer 37

Inhibit nucleosides by competing for substrates
Terminate elongation if growing DNA/RNA chains
Form tight dead end complexes