MCB6937 FINAL EXAM
QUESTIONS AND CORRECT
ANSWERS
Quiz 10:
What is Dr. William Prusoff known for? - ANSWER Developed the first antiviral drug
Quiz 10:
Fascarnet is an antiviral drug that mimics pyrophosphate. Therefore, it inhibits viral
replication by binding to an inhibiting ___. - ANSWER DNA Polymerase
Quiz 10:
Which of the following describes the function of viral integrase inhibitors? - ANSWER
Inhibit incorporation of the viral DNA into the host genome
Quiz 10:
Viral entry inhibitors function by interfering with which of the following processes?
(Check all that apply) - ANSWER -Membrane fusion
-Genetic injection
-Endocytosis
NOT:
-Conjugation
Quiz 10:
Drug-target modification is a mechanism of viral resistance commonly seen with which
of he following drugs?
(Check all that apply) - ANSWER -Reverse transcriptase inhibitors
-Protease inhibitors
-Integrase inhibitors
-Nucleoside analogs
Quiz 10:
,NS5B is a drug that targets HCV RNA polymerase. The viral mechanism of resistance
against NS5B bears no fitness costs.
True/False - ANSWER FALSE
-any mechanism that changes enzymes, RNA or DNA polymerase has a fitness cost
Quiz 10:
Which of the following group is at the highest risk of contracting a subcutaneous
mycosis? - ANSWER Agricultural workers, miners, and gardeners
Quiz 10:
Which of the following statements are true about Candida auris?
(Select all that apply) - ANSWER -Associated with extended hospital stays
-Emerging MDR yeast
Quiz 10:
Fungi develop resistance to flucytosine using which of the following mechanisms? -
ANSWER Prevention of activation
Quiz 10:
Azoles represent one of the largest classes of antifungals. What is the mechanism of
action of azoles? - ANSWER Inhibition of sterol synthesis
*KNOW* Viral Characteristics - ANSWER Contain a *single* type of nucleic acid
-RNA or DNA
-NEVER both
Contain a protein coat that surrounds the nucleic acid
-sometimes the virus itself is *Enveloped*, enclosed by lipids, proteins, and
carbohydrates
-Envelopes make viruses more susceptible to disinfectants
Non-enveloped Viruses
-highly resistant to disinfectants
Multiply inside living cells by using the synthesizing machinery of the cell
-obligatory intracellular parasites
-absolutely *require* host cells to replicate
,Causes the synthesis of specialized structures that can transfer the viral nucleic acid to
other cells
*KNOW* How to kill something that does not live? - ANSWER Problem:
-not a lot of targets
-high replication rate = high mutation rate
-*Drives evolution of resistance*
Different shapes:
-*Polyhedral* (Polio)
-*Helical* (Ebola, Rabies)
-*Complex* (Bacteriophage)
-*Spherical* (Influenza)
*KNOW* Viral Replication -
Lytic Cycle - ANSWER *Lytic*
= viral replication results in death and lysis of host cells
Steps:
-attachment
-penetration
-synthesis/replication
-assembly
-release (through lysis, ready to infect cells)
*Lysogenic*
= viral DNA gets incorporated into the host genome ad remains latent until activated
*KNOW* Lytic Virus Movie - ANSWER HIV is a typical retrovirus
= has an outer envelope
HIV has *2 copies of RNA* and an enzyme that is a *reverse transcriptase*
-will ultimately turn RNA into DNA
HIV itself directly infected *T-helper Cells*
, -comes to cell surface, uses receptors/CD4 molecules on Th
-*CD4* is a surface receptor that binds to the envelope protein
-causes a conformational change and allows a *second receptor* to grab hold of the
envelope (*Chemokine Coreceptor 5/ CCR5*)
-Stalk of the envelope protein then pierces through the host cell membrane, eventually
fusing the 2 viral and host membranes
-viral genetic material is injected into the cell, and envelope protein is left at cell surface
Virus has a *matrix* and a *capsid protein*
-they are digested when enter the cell
-releases viral enzymes and viral RNA
*Reverse transcriptase* takes the viral RNA, and using host nucleosides, converts the
viral RNA into ssDNA
-while doing this, makes random errors
(characteristic of Reverse Transcriptase = poor proofreading activities)
-ssDNA is again reverse transcribed into dsDNA
-*Integrase* (enzyme that also came in which virus) grabs dsDNA
-carries dsDNA through nuclear pore and into nucleus of cell
Within nucleus, *Integrase* carrying dsDNA finds host chromosome
-Integrase enzyme makes a nick in the host DNA, allowing for HIV dsDNA to insert itself
into host chromosome
-*what established lifelong infection*
*RNA polymerase* then makes mRNA, which encodes for various viral proteins
-mRNA associates with ribosomes at surface of Rough Endoplasmic Reticulum (RER)
-Parts are then shuttled through Endoplasmic Reticulum (ER) to cell's surface
-embeds on cellular membrane, coalesces with other envelope proteins/parts
(makes cluster of proteins on surface of infected cell)
-Alongside envelope protein, several other protein parts
*KNOW* Common Viruses - ANSWER Human Viruses:
-Hep B Virus
QUESTIONS AND CORRECT
ANSWERS
Quiz 10:
What is Dr. William Prusoff known for? - ANSWER Developed the first antiviral drug
Quiz 10:
Fascarnet is an antiviral drug that mimics pyrophosphate. Therefore, it inhibits viral
replication by binding to an inhibiting ___. - ANSWER DNA Polymerase
Quiz 10:
Which of the following describes the function of viral integrase inhibitors? - ANSWER
Inhibit incorporation of the viral DNA into the host genome
Quiz 10:
Viral entry inhibitors function by interfering with which of the following processes?
(Check all that apply) - ANSWER -Membrane fusion
-Genetic injection
-Endocytosis
NOT:
-Conjugation
Quiz 10:
Drug-target modification is a mechanism of viral resistance commonly seen with which
of he following drugs?
(Check all that apply) - ANSWER -Reverse transcriptase inhibitors
-Protease inhibitors
-Integrase inhibitors
-Nucleoside analogs
Quiz 10:
,NS5B is a drug that targets HCV RNA polymerase. The viral mechanism of resistance
against NS5B bears no fitness costs.
True/False - ANSWER FALSE
-any mechanism that changes enzymes, RNA or DNA polymerase has a fitness cost
Quiz 10:
Which of the following group is at the highest risk of contracting a subcutaneous
mycosis? - ANSWER Agricultural workers, miners, and gardeners
Quiz 10:
Which of the following statements are true about Candida auris?
(Select all that apply) - ANSWER -Associated with extended hospital stays
-Emerging MDR yeast
Quiz 10:
Fungi develop resistance to flucytosine using which of the following mechanisms? -
ANSWER Prevention of activation
Quiz 10:
Azoles represent one of the largest classes of antifungals. What is the mechanism of
action of azoles? - ANSWER Inhibition of sterol synthesis
*KNOW* Viral Characteristics - ANSWER Contain a *single* type of nucleic acid
-RNA or DNA
-NEVER both
Contain a protein coat that surrounds the nucleic acid
-sometimes the virus itself is *Enveloped*, enclosed by lipids, proteins, and
carbohydrates
-Envelopes make viruses more susceptible to disinfectants
Non-enveloped Viruses
-highly resistant to disinfectants
Multiply inside living cells by using the synthesizing machinery of the cell
-obligatory intracellular parasites
-absolutely *require* host cells to replicate
,Causes the synthesis of specialized structures that can transfer the viral nucleic acid to
other cells
*KNOW* How to kill something that does not live? - ANSWER Problem:
-not a lot of targets
-high replication rate = high mutation rate
-*Drives evolution of resistance*
Different shapes:
-*Polyhedral* (Polio)
-*Helical* (Ebola, Rabies)
-*Complex* (Bacteriophage)
-*Spherical* (Influenza)
*KNOW* Viral Replication -
Lytic Cycle - ANSWER *Lytic*
= viral replication results in death and lysis of host cells
Steps:
-attachment
-penetration
-synthesis/replication
-assembly
-release (through lysis, ready to infect cells)
*Lysogenic*
= viral DNA gets incorporated into the host genome ad remains latent until activated
*KNOW* Lytic Virus Movie - ANSWER HIV is a typical retrovirus
= has an outer envelope
HIV has *2 copies of RNA* and an enzyme that is a *reverse transcriptase*
-will ultimately turn RNA into DNA
HIV itself directly infected *T-helper Cells*
, -comes to cell surface, uses receptors/CD4 molecules on Th
-*CD4* is a surface receptor that binds to the envelope protein
-causes a conformational change and allows a *second receptor* to grab hold of the
envelope (*Chemokine Coreceptor 5/ CCR5*)
-Stalk of the envelope protein then pierces through the host cell membrane, eventually
fusing the 2 viral and host membranes
-viral genetic material is injected into the cell, and envelope protein is left at cell surface
Virus has a *matrix* and a *capsid protein*
-they are digested when enter the cell
-releases viral enzymes and viral RNA
*Reverse transcriptase* takes the viral RNA, and using host nucleosides, converts the
viral RNA into ssDNA
-while doing this, makes random errors
(characteristic of Reverse Transcriptase = poor proofreading activities)
-ssDNA is again reverse transcribed into dsDNA
-*Integrase* (enzyme that also came in which virus) grabs dsDNA
-carries dsDNA through nuclear pore and into nucleus of cell
Within nucleus, *Integrase* carrying dsDNA finds host chromosome
-Integrase enzyme makes a nick in the host DNA, allowing for HIV dsDNA to insert itself
into host chromosome
-*what established lifelong infection*
*RNA polymerase* then makes mRNA, which encodes for various viral proteins
-mRNA associates with ribosomes at surface of Rough Endoplasmic Reticulum (RER)
-Parts are then shuttled through Endoplasmic Reticulum (ER) to cell's surface
-embeds on cellular membrane, coalesces with other envelope proteins/parts
(makes cluster of proteins on surface of infected cell)
-Alongside envelope protein, several other protein parts
*KNOW* Common Viruses - ANSWER Human Viruses:
-Hep B Virus
