Viruses - MBIO 3400 (Exam 3) with complete
solutions graded A+
What contributions did Dmitri Ivanovsky, Martinus Beijerinck, Friedrich Loeffler
and Paul Frosch, Peyton Rous, Frederick Tort, and Felix d'Herelle make in the
history of virology? - correct answer ✔✔-Dimitri Ivanovsky: tobacco mosaic
disease is caused by an infectious agent (1892)
-Martinus Beijerinck: the infectious agent that causes tobacco mosaic disease is
not a bacterium (1898)
-Friedrich Loeffler & Paul Frosch: foot-and-mouth disease in animals is caused by a
virus (1898)
-Peyton Rous: malignant sarcomas in chickens are caused by a virus (1911)
-Frederick Twort & Felix d'Herelle: discovery of the first bacteria viruses
(bacteriophages) (1915 & 1917)
In general terms, what techniques are used to grow viruses in the laboratory? -
correct answer ✔✔Did this in lab (plaque assay, lytic stages). Usually assume a
single particle infected a virus to begin with to create a plaque (like a bacteria and
colony relationship).
What is a plaque? What do we usually assume about the viruses in a single,
isolated plaque? - correct answer ✔✔-An area of disintegrating bacterial cells in a
lawn of bacteria in a Petri plate that looks as if they were being eaten.
-bacteriophages are what cause the plaque
-They are roughly spherical
What are the three basic shapes of virus particles? - correct answer ✔✔-Helical
solutions graded A+
What contributions did Dmitri Ivanovsky, Martinus Beijerinck, Friedrich Loeffler
and Paul Frosch, Peyton Rous, Frederick Tort, and Felix d'Herelle make in the
history of virology? - correct answer ✔✔-Dimitri Ivanovsky: tobacco mosaic
disease is caused by an infectious agent (1892)
-Martinus Beijerinck: the infectious agent that causes tobacco mosaic disease is
not a bacterium (1898)
-Friedrich Loeffler & Paul Frosch: foot-and-mouth disease in animals is caused by a
virus (1898)
-Peyton Rous: malignant sarcomas in chickens are caused by a virus (1911)
-Frederick Twort & Felix d'Herelle: discovery of the first bacteria viruses
(bacteriophages) (1915 & 1917)
In general terms, what techniques are used to grow viruses in the laboratory? -
correct answer ✔✔Did this in lab (plaque assay, lytic stages). Usually assume a
single particle infected a virus to begin with to create a plaque (like a bacteria and
colony relationship).
What is a plaque? What do we usually assume about the viruses in a single,
isolated plaque? - correct answer ✔✔-An area of disintegrating bacterial cells in a
lawn of bacteria in a Petri plate that looks as if they were being eaten.
-bacteriophages are what cause the plaque
-They are roughly spherical
What are the three basic shapes of virus particles? - correct answer ✔✔-Helical
