Question 1

A Type I membrane protein has which of the following structures?

Accepted Answer

A)  Both the C-terminus and the N-terminus face the inside of the virion. 
B)  It passes through the viral envelope multiple times. 
C)  The N-terminus faces outside the virion and the C-terminus faces inside the virion. 
D)  The N-terminus faces inside the virion and the C-terminus faces outside the virion. 
E)  The protein lacks a transmembrane domain and is secreted from the infected cell. 
A)  Both the C-terminus and the N-terminus face the inside of the virion. 
B)  It passes through the viral envelope multiple times. 
C)  The N-terminus faces outside the virion and the C-terminus faces inside the virion. 
D)  The N-terminus faces inside the virion and the C-terminus faces outside the virion. 
E)  The protein lacks a transmembrane domain and is secreted from the infected cell. C

Question 2

Which of the following is a description of a scaffolding protein?

Accepted Answer

A)  A cellular protein that acts as a chaperone during assembly of a helical capsid. 
B)  A viral protein that is used on the outside of an icosahedral capsid during assembly. 
C)  A viral protein used on the inside of an icosahedral capsid during assembly and then removed. 
D)  A protease that trims the proteins during assembly of an icosahedral capsid. 
E)  A energy dependent motor used to package the genome into larger icosahedral capsids. 
A)  A cellular protein that acts as a chaperone during assembly of a helical capsid. 
B)  A viral protein that is used on the outside of an icosahedral capsid during assembly. 
C)  A viral protein used on the inside of an icosahedral capsid during assembly and then removed. 
D)  A protease that trims the proteins during assembly of an icosahedral capsid. 
E)  A energy dependent motor used to package the genome into larger icosahedral capsids. C

Question 3

Virions are often described as being energetically "metastable".What does this mean and why is it important for entry and uncoating of the viral genome into the next host cell?

Accepted Answer

Virons are described as "metastable" because they are not at their lowest, most stable, energy state.If they were, they would not be able to "pop open" to release the genome in the next host cell.Instead, they are like a "Jack-in-the-box", primed to spring open and release the genome after some triggering event.The triggering event that causes the virion to open and release the genome is often the interaction with the host cell receptor or some other change, like a drop in pH, that occurs during attachment and entry.Often proteolytic cleavage of a virion protein is involved in setting up the metastable state and "setting the spring" that will eventually allow the virion to pop open.

Question 4

A packaging sequence is involved in which of the following assembly processes?

Accepted Answer

A)  The assembly of the capsid around the genomic nucleic acid. 
B)  The correct binding of capsid proteins to each other. 
C)  The insertion of the viral glycoproteins in the envelope. 
D)  The acquisition of the envelope by the capsid. 
E)  The packaging of the matrix proteins into the virion. 
A)  The assembly of the capsid around the genomic nucleic acid. 
B)  The correct binding of capsid proteins to each other. 
C)  The insertion of the viral glycoproteins in the envelope. 
D)  The acquisition of the envelope by the capsid. 
E)  The packaging of the matrix proteins into the virion.

Question 5

Some viruses particles have a rigid capsid surrounding an internal membrane.

Accepted Answer

A) True 
 B)False

Question 6

Virus particles can be visualized with which of the following?

Accepted Answer

A)  negative staining of virions with electron microscopy 
B)  negative staining of virions with x-ray diffraction 
C)  negative staining of thin sections of infected cells with electron microscopy 
D)  positive staining in cryoelectron microscopy 
E)  positive staining of infected cells with x-ray diffraction 
A)  negative staining of virions with electron microscopy 
B)  negative staining of virions with x-ray diffraction 
C)  negative staining of thin sections of infected cells with electron microscopy 
D)  positive staining in cryoelectron microscopy 
E)  positive staining of infected cells with x-ray diffraction

Question 7

A very common structure for bacteriophage particles is which of the following?

Accepted Answer

A)  an icosahedral head and an envelope 
B)  a naked icosahedral head 
C)  a naked helical tail 
D)  an icosahedral head with a helical tail 
E)  a cubic head with a helical tail 
A)  an icosahedral head and an envelope 
B)  a naked icosahedral head 
C)  a naked helical tail 
D)  an icosahedral head with a helical tail 
E)  a cubic head with a helical tail

Question 8

The capsid of SV40 contains 360 protein copies.Why is this unusual?

Accepted Answer

A)  There is only 1 kind of protein in this capsid. 
B)  360 is not the correct number of protein capsids for a T = 6 capsid. 
C)  Six is not a mathematically allowed triangulation number. 
D)  The proteins have equivalent interactions. 
E)  The capsid is not large enough to hold the entire genome. 
A)  There is only 1 kind of protein in this capsid. 
B)  360 is not the correct number of protein capsids for a T = 6 capsid. 
C)  Six is not a mathematically allowed triangulation number. 
D)  The proteins have equivalent interactions. 
E)  The capsid is not large enough to hold the entire genome.

Question 9

What does the term "quasi-equivalent" mean with respect to the proteins in an icosahedral capsid?

Accepted Answer

A)  If the identical protein is used, it has both 5-fold and 6-fold interactions with the other proteins in the capsid. 
B)  There are different proteins in the capsid with similiar shapes. 
C)  They all use the "jelly-roll" protein structure. 
D)  There can be more than one type of glycoprotein in the envelope. 
E)  All of the proteins interact in a 5-fold arrangement. 
A)  If the identical protein is used, it has both 5-fold and 6-fold interactions with the other proteins in the capsid. 
B)  There are different proteins in the capsid with similiar shapes. 
C)  They all use the "jelly-roll" protein structure. 
D)  There can be more than one type of glycoprotein in the envelope. 
E)  All of the proteins interact in a 5-fold arrangement.

Question 10

It is possible to get high resolution images of enveloped virus particles using x-ray diffraction.

Accepted Answer

A) True 
 B)False

Question 11

Most viruses that use a spherical shaped capsid arrange their capsid proteins with which of the following symmetries?

Accepted Answer

A)  cubic 
B)  tetrahedral 
C)  icosahedral 
D)  dodecagon 
E)  helical 
A)  cubic 
B)  tetrahedral 
C)  icosahedral 
D)  dodecagon 
E)  helical

Question 12

Which of the following h and k values will produce a triangulation number of 13?

Accepted Answer

A)  1 and 1 
B)  1 and 2 
C)  1 and 3 
D)  2 and 3 
E)  2 and 4 
A)  1 and 1 
B)  1 and 2 
C)  1 and 3 
D)  2 and 3 
E)  2 and 4

Question 13

In a helical nucleocapsid, which of the following MOST affects the LENGTH of the capsid?

Accepted Answer

A)  the (mu) value 
B)  the (rho) value 
C)  the size of the genome and the P (pitch) of the helix 
D)  the size of the capsid protein 
E)  None of the above. 
A)  the (mu) value 
B)  the (rho) value 
C)  the size of the genome and the P (pitch) of the helix 
D)  the size of the capsid protein 
E)  None of the above.

Question 14

Viral envelopes often have very different lipid compositions than the cellular membranes that they originate from.

Accepted Answer

Quasi-equivalence describes the situatio

Question 15

A scaffolding protein is important for assembly of an icosahedral capsid…..

Accepted Answer

A)  but does not bind to the viral genome. 
B)  but does not become part of the final virion. 
C)  and helps to cut the genome into unit lengths. 
D)  and binds to the host cell receptor. 
E)  and assists the virion in exiting the host cell. 
A)  but does not bind to the viral genome. 
B)  but does not become part of the final virion. 
C)  and helps to cut the genome into unit lengths. 
D)  and binds to the host cell receptor. 
E)  and assists the virion in exiting the host cell.

Question 16

Cryoelectron microscopy uses computer reconstruction of images of multiple virions to produce a high resolution image of a virion or capsid.

Accepted Answer

A) True 
 B)False

Question 17

The nucleocapsid describes the structure that includes the:

Accepted Answer

A)  capsid and the genome 
B)  capsid and the envelope 
C)  envelope and the glycoproteins 
D)  helical capsid and an envelope 
E)  icosahedral capsid and an envelope 
A)  capsid and the genome 
B)  capsid and the envelope 
C)  envelope and the glycoproteins 
D)  helical capsid and an envelope 
E)  icosahedral capsid and an envelope

Question 18

Which of the following describes the number of subunits per turn in a helical capsid?

Accepted Answer

A)  P (pitch) 
B)  (mu) 
C)  (rho) 
D)  Triangulation number 
E)  symmetry 
A)  P (pitch) 
B)  (mu) 
C)  (rho) 
D)  Triangulation number 
E)  symmetry

Question 19

The Jelly Roll barrel is:

Accepted Answer

A)  a structure found in many viral envelope glycoproteins. 
B)  a structure found in many viral capsid proteins. 
C)  the structure the viral genome takes inside of a helical capsid. 
D)  the structure the viral genome takes inside an icosahedral capsid. 
E)  the structure of many helical capsids as the wrap around the genome. 
A)  a structure found in many viral envelope glycoproteins. 
B)  a structure found in many viral capsid proteins. 
C)  the structure the viral genome takes inside of a helical capsid. 
D)  the structure the viral genome takes inside an icosahedral capsid. 
E)  the structure of many helical capsids as the wrap around the genome.

Question 20

Enveloped virions assemble and acquire their envelope by which of the following mechanisms?

Accepted Answer

A)  The nucleocapsids interact directly with the cytoplasmic tails of the envelope glycoproteins and bud through the cellular membrane. 
B)  The nucleocapsids interact with the matrix protein, which interact with the cytoplasmic tails of the envelope glycoprotein, and the virion buds through the cellular membrane. 
C)  The envelope is assembled de novo around the nucleocapsid by cellular enzymes. 
D)  The virion acquires the envelope after it leaves the host cell from extracellular vesicles. 
E)  Both a and b are used by viruses. 
A)  The nucleocapsids interact directly with the cytoplasmic tails of the envelope glycoproteins and bud through the cellular membrane. 
B)  The nucleocapsids interact with the matrix protein, which interact with the cytoplasmic tails of the envelope glycoprotein, and the virion buds through the cellular membrane. 
C)  The envelope is assembled de novo around the nucleocapsid by cellular enzymes. 
D)  The virion acquires the envelope after it leaves the host cell from extracellular vesicles. 
E)  Both a and b are used by viruses.

Exam 2: Virus Structure and Assembly

A Type I membrane protein has which of the following structures?

Which of the following is a description of a scaffolding protein?

Virions are often described as being energetically "metastable".What does this mean and why is it important for entry and uncoating of the viral genome into the next host cell?

A packaging sequence is involved in which of the following assembly processes?

Some viruses particles have a rigid capsid surrounding an internal membrane.

Virus particles can be visualized with which of the following?

A very common structure for bacteriophage particles is which of the following?

The capsid of SV40 contains 360 protein copies.Why is this unusual?

What does the term "quasi-equivalent" mean with respect to the proteins in an icosahedral capsid?

It is possible to get high resolution images of enveloped virus particles using x-ray diffraction.

Most viruses that use a spherical shaped capsid arrange their capsid proteins with which of the following symmetries?

Which of the following h and k values will produce a triangulation number of 13?

In a helical nucleocapsid, which of the following MOST affects the LENGTH of the capsid?

Viral envelopes often have very different lipid compositions than the cellular membranes that they originate from.

A scaffolding protein is important for assembly of an icosahedral capsid…..

Cryoelectron microscopy uses computer reconstruction of images of multiple virions to produce a high resolution image of a virion or capsid.

The nucleocapsid describes the structure that includes the:

Which of the following describes the number of subunits per turn in a helical capsid?

The Jelly Roll barrel is:

Enveloped virions assemble and acquire their envelope by which of the following mechanisms?

Introduction to Virology

Virus Classification: The World of Viruses

Virus Entry

Single-Stranded RNA Bacteriophages

Microviruses

Bacteriophage

Bacteriophage Lambda

Viruses of Archaea

Cucumber Mosaic Virus

Picornaviruses

Flaviviruses

Togaviruses

Coronaviruses

Paramyxo-Viruses and Rhabdoviruses

Filovirouses

Bunyaviruses

Influenza Viruses

Reoviruses

Parvoviruses

Polyomaviruses

Papillomaviruses

Adenoviruses

Herpesviruses

Baculoviruses

Poxviruses

Viruses of Algae and Mimivirus

Retroviruses

Human Immunodeficiency

Hepadnaviruses

Viroids and Hepatitis Delta Virus

Prions

Intrinsic Cellular Defenses Against Virus Infection

Innate and Adaptive Immune Responses to Virus Infection

Antiviral Vaccines

Antiviral Chemotherapy

Eukaryotic Virus Vectors

Filters