Deck 11: Viral Molecular Biology

Question 1

Five 5S units are packed into a pentamer, __________ of which assemble to build the icosahedral capsid of poliovirus.

A) 2
B) 5
C) 8
D) 10
E) 12

Answer 1

E

Question 2

Phage T4 is completely virulent and can only carry out a __________ cycle.

A) lysogenic
B) lytic
C) temperate
D) quiescent
E) slow release

Answer 2

B

Question 3

Most virus particles produced from an influenza virus infection are __________.

A) nonfunctional
B) virulent
C) lytic
D) lysogenic
E) mutated

Answer 3

A

Question 4

__________ primers are unique to viruses.

A) mRNA
B) Protein
C) DNA
D) tRNA
E) rRNA

Question 5

Poliovirus infection is insensitive __________ to, a drug that inhibits the exit of endocytosed viruses from an endosome.

A) acyclovir
B) tamiflu
C) AZT
D) cipro
E) bafilomycin

Question 6

The influenza reassortment process is enhanced by a particular feature of the virus, namely, the __________ genome.

A) linear
B) circular
C) double-stranded
D) single-stranded
E) segmented

Question 7

The __________ separation of early genes and late genes is common to the replicative cycles of many phages as well as viruses of eukaryotes.

A) spatial
B) physical
C) temporal
D) genetic
E) lytic

Question 8

Influenza shows cyclic appearance of extremely virulent strains that cause __________ mortality, such as that of 1918, which infected 20% of the world's population and killed more people than World War I.

A) mutation
B) complete
C) epidemic
D) pandemic
E) transgenic

Question 9

The polio mouse was the first example of a/an __________ animal created as a model system for a human disease.

A) transgenic
B) oncogenic
C) infective
D) transfer vector
E) transgene

Question 10

Which of the following is NOT a picornavirus?

A) poliovirus
B) coxsackievirus
C) influenza virus
D) rhinovirus
E) aphthovirus

Question 11

Viruses release into the blood, a condition known as __________, facilitates dissemination across the __________ barrier.

A) septicemia; lymphoid tissue
B) viremia; intestinal lining
C) viremia; blood-brain
D) bacteremia; blood-brain
E) bacteremia; intestinal lining

Question 12

A cell infected with a bacteriophage T4 mutant in tail fiber assembly will accumulate:

A) individual heads and tails
B) heads only
C) tails only
D) heads joined to tails
E) protein subunits for all components

Question 13

Which of the following best describes the genome of influenza virus?

A) negative strand segmented RNA
B) positive strand segmented RNA
C) negative strand single-piece RNA
D) positive strand single-piece RNA
E) double-stranded RNA

Question 14

Flu pandemics are associated with reassortment of which virus genes?

A) hemagglutinin
B) neuraminidase
C) matrix
D) A and B
E) all of the above

Question 15

Mutations that allow viruses to replicate under one set of conditions but not under another set of conditions are known as __________ mutations.

A) suppressor
B) lethal
C) conditional lethal
D) silent
E) nonsense

Question 16

Some polio virions may cross the blood-brain barrier to infect __________, causing paralysis.

A) intestinal lining
B) lymphoid tissue
C) neurons
D) muscles
E) GALT

Question 17

__________ primers, for nucleic acid synthesis, are common in many kinds of viruses.

A) RNA
B) DNA
C) Polymerase
D) Protein
E) Protease

Question 18

In phage T4, the sheath plus the internal __________ comprise the tail.

A) tube
B) capsid
C) envelope
D) fibers
E) nucleic acid

Question 19

Phage T4 genes are translated using host cell __________ and viral __________.

A) polymerases; ribosomes
B) ribosomes; tRNA
C) tRNA; ribosomes
D) tRNA; polymerases
E) mRNA; tRNA

Question 20

Phage T4 requires how many gene products for assembly?

A) 2
B) 5
C) 10
D) 15
E) 20

Question 21

The __________ virus envelope proteins needed to recognize the specific protein sequence of CD4 and CCR5 in order to attach and enter the host cell.

A) HIV
B) influenza
C) T4
D) M13
E) polio

Question 22

The double-stranded DNA copy of HIV:

A) enters the nucleus from the cytoplasm
B) is synthesized in the nucleus
C) encodes an integrase prior to integration
D) contains hydroxymethylcytosine
E) has RNAase activity

Question 23

Which was the first virus demonstrated to cause cancer?

A) human immunodeficiency virus
B) Rous sarcoma virus
C) herpes simplex virus
D) coxsackievirus
E) rhinovirus

Question 24

A fusion peptide is associated with which virus influenza virus protein?

A) hemagglutinin
B) neuraminidase
C) matrix
D) nuclear-packaging protein
E) cap-stealing protein

Question 25

The causative agent of chickenpox is:

A) herpes simplex virus-1
B) herpes simplex virus-2
C) varicella-zoster virus
D) Epstein-Barr virus
E) HIV

Question 26

The pol open reading frame of HIV encodes:

A) reverse transcriptase
B) integrase
C) protease
D) all of the above
E) none of the above

Question 27

Cyclophilin A is a host protein that:

A) acts as a coreceptor for HIV
B) facilitates HIV entry into the nucleus
C) is incorporated in the HIV envelope
D) inhibits HIV replication
E) cuts the polyprotein into subunits

Question 28

We now believe that a __________ must have existed very early in the evolution of all cells because something had to copy the information from the ancient "RNA world" cell into the DNA of modern genomes.

A) reverse transcriptase
B) polymerase
C) telomerase
D) gyrase
E) retroelement

Question 29

RNA synthesis of influenza virus is primed by capped fragments of host mRNA, obtained by the "__________" method.

A) telomerase
B) rolling-circle
C) endocytosis
D) exocytosis
E) cap-snatching

Question 30

Some people are resistant to HIV infection because they:

A) lack CD4 receptors on their macrophages
B) lack CCR5 receptors on their macrophages
C) lack macrophages
D) produce proteases that destroy HIV
E) all of the above

Question 31

Which of the following is NOT an accessory protein found in HIV?

A) Nef
B) Vpu
C) Tat
D) Rev
E) Gag

Question 32

Worldwide, HIV infects one in how many adults?

A) 20
B) 50
C) 100
D) 500
E) 1,000

Question 33

Glycosylation and packaging of the HIV Env proteins occur in the:

A) endoplasmic reticulum
B) nucleus
C) membrane
D) Golgi
E) cytoplasm

Question 34

The native type of reverse transcriptase in animal cells is called __________.

A) polymerase
B) telomerase
C) ligase
D) helicase
E) gyrase

Question 35

The RNA dimer packed in the HIV virion includes two host tRNA molecules hybridized so as to present a 3' OH for __________ synthesis of DNA.

A) increasing
B) preventing
C) priming
D) decreasing
E) terminating

Question 36

HIV-infected cells can fuse with a neighboring cell, resulting in the formation of a giant multinucleate cell called a __________.

A) transgene
B) syncytium
C) oncogene
D) tumor
E) retroelement

Question 37

AZT, a component in the drug mixture given to AIDS patients, is an inhibitor of __________.

A) exit of endocytosed viruses
B) endocytosis
C) viral assembly
D) reverse transcriptase
E) viral polymerase

Question 38

In evolution, __________ leads to the gradual loss of unselected traits.

A) natural selection
B) mutation
C) epidemic
D) pandemic
E) infection

Question 39

Integrated retrovirus genomes that have accumulated mutations and no longer can generate virions are known as __________ retroviruses.

A) lysogenic
B) temperate
C) virulent
D) exogenous
E) endogenous

Question 40

Which of the following primers for nucleic acid replication is linked to the appropriate virus?

A) M2 and poliovirus
B) host caps and poliovirus
C) Vpg and influenza virus
D) virus tRNA and herpes virus
E) host tRNA and HIV

Question 41

Herpes simplex virus-1 capsids receive envelope proteins from:

A) the cytoplasm
B) the nuclear membrane
C) the ER
D) either the nuclear membrane or the ER
E) the Golgi

Question 42

Which of the following are NOT ways that viral vectors are modified to be made safer?

A) deleting virulence genes
B) avoiding genome insertion next to oncogenes
C) altering tissue specificity
D) using viruses that will trigger an immune response
E) avoiding germ line infection

Question 43

The segmented genome of influenza virus makes virus assembly problematic. How does the assembly mechanism package exactly eight segments correctly?

Question 44

Why are capsids of icosahedral symmetry so common among viruses?

Question 45

During latent herpes virus infections:

A) the virus produces early proteins but not late proteins
B) a latency associated transcript is produced
C) no viral transcription occurs
D) virus DNA is integrated into host DNA
E) cell transcription machinery is silenced

Question 46

How are humans infected with poliovirus? Describe the possible effects of the virus on humans.

Question 47

How is the poliovirus genome replicated?

Question 48

Herpes simplex virus and varicella-zoster virus cause primary __________ infections.

A) muscle
B) brain
C) neuron
D) epithelial
E) bone

Question 49

Describe how priming is different for mRNA synthesis or template synthesis for viral progeny of influenza A virus.

Question 50

Which type of virus has been used experimentally to transfer genes to Alzheimer's patients to promote nerve regeneration?

A) lentivirus
B) adenovirus
C) poliovirus
D) influenza virus
E) T4

Question 51

What is meant by early and late genes of phage T4? What do they encode?

Question 52

Approximately 60-80% of Americans acquire herpes simplex, usually HSV-1, in epithelial lesions commonly known as __________.

A) chancres
B) pox
C) cold sores
D) shingles
E) hives

Question 53

Describe the two different times phage T4 uses virally produced lysozyme during its infection cycle.

Question 54

Mimivirus is the first virus that contains genes for the synthesis of:

A) DNA polymerase
B) reverse transcriptase
C) amino-acyl tRNA synthetase
D) ATP synthase
E) ribosomal RNA

Question 55

What is a conditional lethal mutant? Give examples of two classes of conditional lethal mutants produced in T4 to demonstrate its assembly.

Question 56

The cell membrane releases mature HSV-1 virions through __________.

A) endocytosis
B) exocytosis
C) lysis
D) budding
E) slow release

Question 57

Why do highly virulent strains of the influenza virus appear periodically?

Question 58

Viruses which specifically infect and lyse tumor cells are:

A) transfer vectors
B) temperate
C) lytic
D) lysogenic
E) oncolytic

Question 59

Why isn't there a cure or vaccine for AIDS yet?

Question 60

Herpes simplex virus-1 replication involves:

A) viral DNA polymerase
B) rolling-circle replication
C) concatamer formation
D) all of the above
E) none of the above

Question 61

What are the different types of retroelements and why do they exist within the human genome?

Question 62

What types of infections are caused by herpes viruses? Describe the two possible types of replication cycles that occur with the herpes viruses.

Question 63

What are some of the safety concerns involving viral vectors? Describe some of the safety features of viral vectors.

Question 64

Describe retroelements that are found in the human genome. How do endogenous retroviruses and retrotransposons differ?

Question 65

Describe the replicative cycle of HIV.

Question 66

Explain what happens in individuals infected with HIV who are homozygous for CCR5, heterozygous for a CCR5 deletion, or homozygous for a CCR5 deletion.

Question 67

Describe the structure of herpes simplex virus. How is the attachment process of herpes simplex virus different that poliovirus and HIV virus?

Question 68

How can viruses be used to treat cancer? What are some features the viruses must have to be used in cancer therapy?

Question 69

What is the role of the variable and constant domains of the spike proteins in HIV infection?

Question 70

How are viruses used in gene therapy? What characteristics are important in viral vectors?