Week 1 Reading Quiz: Class 2

Question 1

What type of device was used that led to the discovery of viruses in the late 1800s?
a
Centrifuge

b
Electron microscope

c
Chamberland Filter

d
Plaque Assay

e
None of the above

Answer 1

b. Chamberland Filter

Question 2

What organism were viruses first discovered in?

a
Animals

b
Humans

c
Bacteria

d
Plants

Answer 2

plants

Question 3

“The key concept made by scientists in the late 1800s was that infectious agents (i.e. viruses) were not only small, but replicated only in the ____, not in the ___.
.

Answer 3

Host; broth

Question 4

Please match the following viruses with the year they were discovered.

Rabies virus

Variola virus (smallpox)

Poliovirus

Bacteriophages

Influenza Virus

Answer 4

Rabies virus- 1903

Variola virus (smallpox)-1906

Poliovirus-1908

Bacteriophages-1915

Influenza Virus-1933

Question 5

What instrument revolutionized Virology and allowed the first direct visualization of virus particles?

Electron microscopy

X-ray crystallography

Centrifuge

Nuclear Magnetic Resonance

Answer 5

Electron Microscopy

Question 6

What model organism/agent was used in the Hershey Chase experiment?

Saccharomyces cerevisiae (Yeast)

Caenorhabditis elegans (Roundworm)

Mus Musculus (mouse)

Bacteriophage

Rous Sarcoma Virus

Answer 6

Bacteriophage

Question 7

How did Hershey and Chase “tag” the bacteriophages and why was this important?

a
They didn’t “tag” anything. They only looked under a microscope to observe transfer of genetic material.

b
Sulfur-35 in the bacteriophage, this was important because it measured whether the protein transferred to the bacterium.

c
Phosphorus-32 in the bacteriophage, this was important because it measured whether the DNA transferred to the bacterium.

d
Phosphorus-32 in the bacterium, this was important because it measured whether the bacterium transferred its DNA to the bacteriophage.

Answer 7

c. Phosphorus-32 in the bacteriophage, this was important because it measured whether the DNA transferred to the bacterium.

Question 8

Which of the following properties of viruses is FALSE?

a
A virus is an infectious obligate intracellular parasite.

b
Viral genomes are composed solely of DNA.

c
The viral genome directs the synthesis of viral components by cellular systems within an appropriate host cell.

d
Infectious progeny virus particles (virions), are formed by de novo self-assembly from newly synthesized components.

e
A progeny virion assembled during the infectious cycle is the vehicle for transmission of the viral genome to the next host cell or organism, where its disassembly initiates the next infectious cycle.

Answer 8

b

Viral genomes are composed solely of DNA.

Question 9

Viruses can be classified by all of the following EXCEPT

a
Genome: Nature of nucleic acid in the virion

b
Shape: Symmetry of protein shell (capsid)

c
Size: Dimensions of the virion and capsid

d
Disease caused by infection

e
Presence or absence of lipid membrane (envelope)

Answer 9

d

Disease caused by infection

Question 10

Direct sequencing of genomes from environmental samples. Detects novel microbial species that is otherwise uncultivatable.

Answer 10

Metagenomics

Question 11

Isolated from Japanese hot spring. Infects amoebae
-cell lysis
develops hard shell or stone cysts

Answer 11

Medusavirus