Acellular Pathogens Chapter 6 Exam Prep

Chapter 6: Acellular Pathogens

= Correct answer

Multiple Choice

1. Which of the following is not a property of a virus?
2. It is an infectious cellular pathogen.
3. It is an obligate intracellular pathogen.
4. Its genome consists of DNA or RNA.
5. Its genome is surrounded by a protein capsid.

Difficulty: Easy

ASM Standard: 10, 13

1. Which of the following is the scientist responsible for first discovering viruses (specifically, tobacco mosaic virus)?
2. Dimitri Ivanovski
3. Edward Jenner
4. Henrietta Lacks
5. Stanley Prusiner

Difficulty: Easy

ASM Standard: N/A

1. The protein subunits that surround the nucleic acid of a virus are known as which of the following?
2. amino acids
3. capsomeres
4. chromatins
5. telomeres

Difficulty: Easy

ASM Standard: N/A

1. Arthropods typically serve as which mechanism of transmission for viruses?
2. biological vector
3. fomite
4. mechanical vector
5. both as fomites and as vectors

Difficulty: Medium

ASM Standard: 10, 13, 23

1. Which unit of length best describes the average size of a virion?
2. mm
3. µm
4. nm
5. pm

Difficulty: Easy

ASM Standard: 6

1. Viruses can be visualized using which method?
2. compound light microscope
3. electron microscope
4. the naked eye
5. ultraviolet rays

Difficulty: Easy

ASM Standard: 6, 32, 36

1. The Baltimore Classification system describes viruses according to which characteristic?
2. capsid shape
3. host-cell susceptibility
4. the presence or absence of an envelope
5. the viral genome

Difficulty: Easy

ASM Standard: 10

1. Which of the following properly lists (in order) the steps of viral replication?
2. 
3. 
4. 
5. 

Difficulty: Easy

ASM Standard: 10

1. In the lysogenic cycle of bacteriophages, the integrated phage genome is known as which of the following?
2. prophage
3. provirus
4. virioid
5. virion

Difficulty: Easy

ASM Standard: 10

1. In retroviruses, the integrated phage genome is known as which of the following?
2. prophage
3. provirus
4. virioid
5. virion

Difficulty: Easy

ASM Standard: 10

1. Which mechanism of horizontal gene transfer relies on the use of viruses?
2. conjugation
3. mutation
4. transduction
5. transformation

Difficulty: Easy

ASM Standard: 2, 4

1. A bacteriophage infects a host cell and the genome integrates itself into the host chromosome. Sometime later, the phage is excised along with a short piece of DNA adjacent to the insertion point. Both the phage DNA and the host DNA are packaged into the same capsid. The bacteriophage then infects a new cell, delivering both phage and bacterial DNA. Which process is being described in this scenario?
2. The lysogenic cycle, reactivating as the lytic cycle, followed by generalized transduction
3. The lysogenic cycle, reactivating as the lytic cycle, followed by specialized transduction
4. The lytic cycle, reactivating as the lysogenic cycle, followed by generalized transduction
5. The lytic cycle, reactivating as the lysogenic cycle, followed by specialized transduction

Difficulty: Medium

ASM Standard: 2, 4, 10

1. (−)ssRNA is transcribed into (+)ssRNA using which of the following?
2. DNA polymerase encoded by the host cell
3. DNA polymerase encoded by the virus
4. RNA polymerase encoded by the host cell
5. RNA polymerase encoded by the virus

Difficulty: Easy

ASM Standard: 16, 18

1. Which of the following is a novel enzyme found in retroviruses?
2. forward transcriptase
3. retrotranscriptase
4. reverse transcriptase
5. Taq polymerase

Difficulty: Easy

ASM Standard: 16, 18, 26

1. Reverse transcriptase is used to generate which nucleic acid from RNA?
2. cDNA
3. dsRNA
4. (+)ssRNA
5. (−)ssRNA

Difficulty: Easy

ASM Standard: 26

1. Which of the following is the host-cell receptor that recognizes human immunodeficiency virus (HIV)?
2. CD4
3. CD8
4. Gp120
5. sialic acid

Difficulty: Hard

ASM Standard: 10

1. Which of the following viruses does not cause latent infections?
2. adenovirus
3. Epstein-Barr virus
4. herpes simplex virus
5. varicella-zoster virus

Difficulty: Medium

ASM Standard: 23

1. Chicken pox can reemerge as which disease?
2. cowpox
3. genital warts
4. shingles
5. smallpox

Difficulty: Easy

ASM Standard: 23

1. The excision of the viral genome from the host chromosome is known as which of the following?
2. induction
3. lysogeny
4. phage conversion
5. transduction

Difficulty: Medium

ASM Standard: 10

1. Which statement regarding the introduction of virus in eggs is true?
2. Pox can form on the embryo.
3. The virus cannot be introduced into the yolk sac.
4. The virus will not kill the embryo if it is introduced early in development.
5. Virus introduction will not disrupt embryonic development.

Difficulty: Medium

ASM Standard: 33

1. The liquid portion of blood that does not contain clotting factors is known as which of the following?
2. erythrocytes
3. plasma
4. platelets
5. serum

Difficulty: Easy

ASM Standard: N/A

1. Which method cannot be used to detect virus in a patient’s serum?
2. EIA
3. hemagglutinin assay
4. growth in pure culture
5. RT-PCR

Difficulty: Medium

ASM Standard: 34

1. You are a nurse and you suspect that you may have been exposed to a particular virus. You and your health care provider decide to perform a hemagglutinin assay. A sample of your serum is taken and added to a sample of virus. Next, the virus and serum sample are added to erythrocytes. Upon examination, you do not see any agglutination occurring. Which can you conclude from these results?
2. The test result suggests you may have been exposed to the virus, and your serum contains antibodies against the virus.
3. The test result suggests you may have been exposed to the virus, but your serum does not contain antibodies against the virus.
4. The test result suggests you may not have been exposed to the virus.
5. You cannot make a conclusion from the information given.

Difficulty: Medium

ASM Standard: 28b, 34, 36

1. Which effect does tomato planta macho viroids have on the crop?
2. browning of fruit
3. crown-gall formation
4. loss of chlorophyll
5. lysis of root cells

Difficulty: Medium

ASM Standard: 23

1. Which scientist first discovered prions?
2. Dimitri Ivanovski
3. Edward Jenner
4. Henrietta Lacks
5. Stanley Prusiner

Difficulty: Easy

ASM Standard: N/A

1. Transmissible spongiform encephalopathies, such as Creutzfeldt-Jakob disease, are caused by which of the following?
2. bacterium
3. fungus
4. prion
5. virus

Difficulty: Easy

ASM Standard: 23

1. How is kuru transmitted?
2. bloodborne transmission
3. contaminated neurosurgical instruments
4. eating contaminated cattle meat
5. eating infected meat through cannibalism

Difficulty: Medium

ASM Standard: N/A

1. An acellular entity composed of a small circular RNA molecule without a capsid and capable of replicating its genome is known as which of the following?
2. satellite RNA
3. virion
4. viroid
5. virusoid

Difficulty: Easy

ASM Standard: 10, 16

1. An acellular entity composed of a small circular RNA molecule without a capsid and is not capable of replicating its genome is known as which of the following?
2. provirus
3. virion
4. viroid
5. virusoid

Difficulty: Easy

ASM Standard: 10, 16

1. Although there are no current treatments for prion infections, which of the following could be used?
2. antibiotics
3. nucleases
4. proteases
5. sulfa drugs

Difficulty: Medium

ASM Standard: N/A

True/False

1. Viruses are facultative intracellular pathogens.

Difficulty: Easy

ASM Standard: 10, 13, 18

1. A zoonosis can only be transmitted from animals to humans.

Difficulty: Medium

ASM Standard: 23

1. Most plant viruses do not kill their host.

Difficulty: Medium

ASM Standard: 23

1. (+)ssRNA can be directly used in translation at the ribosome.

Difficulty: Medium

ASM Standard: 16

1. Any virus can infect any host cell.

Difficulty: Easy

ASM Standard: 16, 23

1. Satellite RNAs can encode for protein.

Difficulty: Medium

ASM Standard: 16

1. There is a cure for transmissible spongiform encephalopathies.

Difficulty: Easy

ASM Standard: 23, 27

1. Prion diseases cannot be transmitted from one generation to the next.

Difficulty: Hard

ASM Standard: 23

1. RT-PCR relies on an enzyme encoded by retroviruses.

Difficulty: Easy

ASM Standard: 26

1. The hemagglutinin assay can only identify infectious virus particles.

Difficulty: Medium

ASM Standard: 34

Matching

1. Match the virus family to its clinical features:

Answers: A. ii., B. i., C. iii., D. v., E. iv.

Difficulty: Medium

ASM Standard: 23

1. Match the virus family to its genome (as defined by the Baltimore classification):

Answers: A. iv., B. i., C. ii., D. v., E. iii.

Difficulty: Hard

ASM Standard: 23

1. Put the steps of HIV infection in order by matching the correct events with each step:

Answers: A. iii., B. v., C. ii., D. iv., E. i.

Difficulty: Medium

ASM Standard: 16, 23

1. Match the virus detection method to its proper description:

Answers: A. i., B. iv., C. ii., D. iii.

Difficulty: Medium

ASM Standard: 34, 36

Fill in the Blank

1. All viruses are composed of ________ and ________.

Difficulty: Easy

ASM Standard: 6

1. Viruses that infect bacterial cells are known as ________.

Difficulty: Easy

ASM Standard: 7, 18

1. ________ is an enzyme used by retroviruses to produce complementary DNA from RNA.

Difficulty: Medium

ASM Standard: 16, 23

1. The lipid content of an enveloped virus is produced from the ________.

Difficulty: Medium

ASM Standard: 10, 18

1. The protein content of an enveloped virus is produced from the ________.

Difficulty: Medium

ASM Standard: 10, 18

1. ________ occurs when a random piece of bacterial chromosomal DNA is transferred by the phage during the lytic cycle.

Difficulty: Easy

ASM Standard: 2, 10, 18

1. The integrated genome of a retrovirus in a host cell is known as ________.

Difficulty: Easy

ASM Standard: 10, 23

1. The number of virions per unit volume is known as the ________.

Difficulty: Easy

ASM Standard: 35

1. When a lawn of bacteria is grown on semisolid medium and those cells are lysed, the clear zones produced are known as ________.

Difficulty: Easy

ASM Standard: 35

1. Proteinaceous infectious particles are known as ________.

Difficulty: Easy

ASM Standard: 23

Short Answer

1. Name two possible shapes for viral capsids.

Sample

Difficulty: Easy

ASM Standard: 6

1. Define the term “tissue tropism.”

Sample

Difficulty: Medium

ASM Standard: 10, 18

1. List, in order, the stages of animal virus replication.

Sample

Difficulty: Easy

ASM Standard: 10

1. What two methods can an enveloped animal virus use to enter a host cell?

Sample

Difficulty: Medium

ASM Standard: 10

1. Why are naked animal viruses unable to enter host cells through membrane fusion?

Sample

Difficulty: Hard

ASM Standard: 10, 18

1. Identify which type of virus is shown in the diagram below. Additionally, indicate what the labels A, B, C, and D represent.

Sample

Difficulty: Medium

ASM Standard: 6

1. On the axes below, sketch the multiplication curve for a bacteriophage population. Be sure to indicate each of the four stages.

Sample

Difficulty: Medium

ASM Standard: 35

1. What is a provirus? How does it compare to a prophage?

Sample

Difficulty: Medium

ASM Standard: 10, 23

1. Briefly describe the difference between the lytic and lysogenic cycles.

Sample

Difficulty: Easy

ASM Standard: 10

1. From where were HeLa cells first isolated? Why are they used in virology?

Sample

Difficulty: Easy

ASM Standard: 23, 33

1. Describe three cytopathic effects of viruses on eukaryotic cells.

Sample

Difficulty: Easy

ASM Standard: 23

1. What is the difference between plasma and serum?

Sample

Difficulty: Medium

ASM Standard: 36

1. What is the difference between viroids and virusoids?

Sample

Difficulty: Easy

ASM Standard: 10, 16, 18

1. What are the two spike proteins of influenza virus?

Sample

Difficulty: Easy

ASM Standard: 6, 23

1. When there was an outbreak of mad cow disease (bovine spongiform encephalopathy) in 2003, everyone was concerned about eating certain beef products but not about eating steak. Why?

Sample

Difficulty: Hard

ASM Standard: 23

Brief Essay

Essay Question Rubric

Assume rating/grading scale for the question ranges from 0 to 3 points.

1. Compare and contrast bacteriophages and animal viruses. In what ways are they the same and in what ways are they different?

Sample

Difficulty: Medium

ASM Standard: 10, 23

1. Chicken pox and shingles are distinctly different diseases but are due to the actions of the same virus. Which virus causes both these diseases? Discuss why different signs and symptoms are observed during the two diseases.

Sample

Difficulty: Medium

ASM Standard: 23

1. When studying bacterial genomes, it is common to find prophages that have never been reactivated. Some of them are also known as “defective prophages,” which can never be reactivated. Genome scientists use these defective prophages to study the ways viruses have shaped the genomes of bacteria. Based on this information, answer the following questions.
2. Define what a prophage is.
3. Explain how prophages normally become activated and what might cause a prophage to become “defective.”
4. Discuss other ways viruses have contributed to the evolution of the genomes of bacteria.

Sample

Difficulty: Hard

ASM Standard: 2, 10, 16, 23

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