Viruses

Question 1

Viral Infection Cycle

Answer 1

Attachement -> Endocytosis -> Uncoating -> Translocation to replication site (nucleus for DNA, cytoplasm for RNA) -> Transcription -> Early protein synthesis (replication proteins) -> Genome replication -> Primary Protein Replication-> Assembly-> Release->

Question 2

+sense ssRNA

Answer 2

Serves as its own mRNA

Question 3

-sense ssRNA

Answer 3

Has to make a complimentary +sense strand

Question 4

Inclusion Bodies

Answer 4

Bodies observable via light microscope that are indicative of viral infection

Question 5

Syncytia

Answer 5

Proteins expressed on surface of viral infected cells that cause it to merge with uninfected cells (Borg proteins)

Question 6

How many RNA segments are in influenza

Answer 6

8

Question 7

Which site on influenza is subject to antigenic variability and which portion of that site is most variable?

Answer 7

Hemagglutanin. Receptor site and structural site can both be genetically modified, both structural (antigenically variable site) can tolerate more change than receptor site.

Question 8

Antigenic drift

Answer 8

slight changes in influenza serotype

Question 9

Antigenic shift

Answer 9

dramatic changes in influenza serotype

Question 10

Which protein codes for proteins that kill alveolar macrophages and lead to pneumonia in influenza infections?

Answer 10

PB1F2

Question 11

Amantadine

Answer 11

Enters Virus through m2 protein, prevents uncoating in type A influenza

Question 12

Tamiflu/Relenza

Answer 12

Prevents cleavage of neurominic acid tether that anchors virus to cell membrane

Question 13

HIV Replication process

Answer 13

HIV recognizes CD4 receptors on host cell (CCR5 and CXCR4). GP120 (the ball) and GP41 (the chain) interact with CD4 receptors and GP120 undergoes conformational change. GP41 inserts into membrane and folds up to fuse with host cell. 2 Viral RNA, integrase, protease, and reverse transcriptase are released into cell. RNA transcribed to DNA via reverse transcriptase. Sticky ends formed and viral DNA inserted into host DNA via integrase. Proteins synthesized Viral proteins specifically cleaved by protease

Question 14

Fuzeon

Answer 14

HIV entry inhibitor Binds to GP41 to prevent conformational changes that lead to binding

Question 15

Miraviroc

Answer 15

CCR5 Coreceptor antagonist Binds CCR5 causing conformational changes which prevent GP120 from attaching

Question 16

Acyclovir

Answer 16

NRTI (nukes) Poisons DNA polymerase of herpes virus. Poses as a nucleoside and prevents or prematurely stops protein synthesis

Question 17

Why can NRTIs be used for an extended length of time, despite developing resistance?

Answer 17

Each NRTI is based off a specific Nucleoside base. Resistance only develops to nucleosides sharing the same base. If HIV is resistant to thymadine based NRTIs, switch the patient to an adenosine based NRTI.

Question 18

Non NRTI

Answer 18

Work at allosteric site of reverse transcriptase. Decrease flexibility of transcription site. Resistance develops quickly, so not used in monotherapy Only works on HIV1

Question 19

Integrase Inhibitors (HIV)

Answer 19

Prevents viral DNA from being integrated into host DNA

Question 20

Protease Inhibitors (HIV)

Answer 20

Binds to active site of protease to prevent protein cleavage. Incremental resistance develops over time.