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. 1. If you inject the genome of Epstein-Barr virus into a cell, it will replicate However, if you take the Epstein-Barr virus genome and treat it with DNAse, an enzyme that degrades DNA, it will not. What kind of genome does Epstein-Barr virus have?
dsDNA
ssDNA
ssRNA (+ strand, picornavirus-like)
ssRNA (- strand)
ssRNA (+ strand, retrovirus-like)
Q. If you inject the nipah virus genome into a cell, it will not replicate. If you co-inject the nipah virus polymerase, it will replicate. Adding DNAses has no effect on the ability of nipah virus to replicate. Based on this evidence, what type of genome does nipah virus have?
dsDNA
ssDNA
ssRNA (+ strand, picornavirus-like)
ssRNA (- strand)
ssRNA (+ strand, retrovirus-like)
Q. If you inject the parvovirus genome into a cell, it will not replicate. If you co-inject the parvovirus polymerase, it will replicate. Adding DNAses will also prevent the virus from replicating. Based on this evidence, what type of genome does parvovirus have?
dsDNA
ssDNA
ssRNA (+ strand, picornavirus-like)
ssRNA (- strand)
ssRNA (+ strand, retrovirus-like)
Q. If you inject foot-and-mouth disease virus genome into a cell, it will replicate. Adding RNAses, or enzymes that degrade RNA, will prevent foot-and-mouth disease virus replication. Based on this evidence, what type of genome does foot-and-mouth disease virus have?
dsDNA
ssDNA
ssRNA (+ strand, picornavirus-like)
ssRNA (- strand)
ssRNA (+ strand, retrovirus-like)
Q. If you inject mouse mammary tumor virus (MMTV) genome into a cell, it will not replicate. If you co-inject the MMTV polymerase, it will replicate. Addition of RNAses inhibits replication, though if MMTV genome and polymerase are mixed and incubated prior addition of RNAses, there is no effect. Based on this evidence, what type of genome does MMTV have?
dsDNA
ssDNA
ssRNA (+ strand, picornavirus-like)
ssRNA (- strand)
ssRNA (+ strand, retrovirus-like)
Q. Why is there a difference in the effect of RNAse addition in the previous question?
RNAses take a while to work.
The MMTV polymerase is a reverse transcriptase, where the RNA genome is converted to a DNA version.
Incubation makes the genome form secondary structures that are RNAse resistant.
The salts in the incubation buffer inhibit RNAse activity.
All of the above
Q. What is an example of a gene that a virus would probably NOT encode?
Polymerase (replicase)
Viral transcription factor
18S ribosome subunit
Host shutoff factor
Capsid
Q. If you inject a virusoid into a cell, it will not replicate. Why not?
Virusoids are too big to be injected into a cell.
Virusoids don’t express proteins.
Virusoids lack a protein coat.
Virusoids require a helper virus for replication.
None of the above
Q. Which is NOT a way non-animal viruses infect cells?
Mechanical transmission
Passage through plasmodesmata from adjacent cells
Damage from vector transmission
Passage from mother to daughter
Microinjection
Q. Which of the following would suggest that a bacterial toxin comes from a phage?
All bacteria that have toxin also have phage genes.
Bacteria can grow in cell culture.
Bacteria do not need lysine for growth.
Bacteria have plasmid DNA.
All of the above