Think you’ve got your head wrapped around Microorganisms: Viruses? Put your knowledge to
the test. Good luck — the Stickman is counting on you!
Q. Which of the following is NOT involved in any type of virus membrane fusion?
Cell receptor
RNA polymerase
Virus glycoprotein
Low pH
Lipid bilayers
Q. If you treat a cell with a membrane-impermeable protease and then add a virus to it, the cell will not be infected. Why not?
The protease removes the virus receptor from the cell.
The protease activates the MAPK pathway.
The protease shuts off cellular endocytosis.
The protease degrades the nucleus.
All of the above
Q. What does the previous answer tell you about the virus?
The virus is protease resistant.
The virus is insensitive to the MAPK pathway.
The virus replicates in the nucleus.
The virus requires a cellular receptor to enter the cell.
The virus is a DNA virus.
Q. How can you prove that a virus does NOT require low pH to enter a cell?
Add anti-retroviral drugs
Perform a PCR on nuclei
Add chemicals that prevent formation of endosomes
Inject reverse transcriptase into cells
Mix infected cells with uninfected cells
Q. Reoviruses will still infect cells if treated with SDS, a harsh detergent that dissolves lipid bilayers. What does this information tell you about reoviruses?
Reoviruses do not infect humans.
Reoviruses are not plant viruses.
Reoviruses have a dsRNA genome.
Reoviruses lack a viral polymerase.
Reoviruses do not have an envelope.
Q. If you infect cells with influenza virus, you can collect virus from the cells in 6 hours, but no cell death is seen. What does this information tell you?
The strain is H1N1.
The strain is H5N1.
Influenza buds out of cells instead of lysing cells.
Influenza is an RNA virus.
This does not tell me anything.
Q. A team of scientists have found that the site of replication of Shmoopvirus is in the cytoplasm. What does this tell you about the genes encoded in the Shmoopvirus genome?
Shmoopvirus encodes its own polymerase gene.
Shmoopvirus is a DNA virus.
Shmoopvirus is an enveloped virus.
Shmoopvirus is highly pathogenic.
Shmoopvirus has a latent stage of replication.
Q. Which of the following viruses would be LEAST affected if you knocked out the host RNA polymerase genes?
dsRNA virus
ssRNA (+ strand, picornavirus-like) virus
ssRNA (- strand) virus
dsDNA virus
None would be affected.
Q. Which of the following viruses would be the MOST affected if you knocked out the host DNA polymerase genes?
ssDNA virus
ssRNA (+ strand, retrovirus-like) virus
ssRNA (+ strand, picornavirus-like) virus
ssRNA (- strand) virus
None would be affected
Q. If you counted 127 plaques in a cell culture dish after you diluted the infected sample 1:100,000 and added 0.1 mL to cells, what is the virus titre?
2.54 × 108 pfu/mL
1.27 × 106 pfu/mL
1.27 × 109 pfu/mL
2.54 × 107 pfu/mL
1.27 × 108 pfu/mL