Chapter 6 Microbiology

Proteinaceous infectious particles are known as ____

prions

Poxviridae

skin lesions

Steps of HIV infection

step 1: HIV RNA and other viral proteins enter the cell. step 2: Viral DNA is synthesized. step 3: Provirus appears. step 4: Viral DNA is transcribed into viral RNA. step 5: New virus particles are released

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

Attachment → Penetration (entry) → Uncoating → Biosynthesis → Assembly → Release

Although there are no current treatments for prion infections, which of the following could be used? A. antibiotics B. nucleases C. proteases D. sulfa drugs

C. proteases

(−)ssRNA is transcribed into (+)ssRNA using which of the following? A. DNA polymerase encoded by the host cell B. DNA polymerase encoded by the virus C. RNA polymerase encoded by the host cell D. RNA polymerase encoded by the virus

D. RNA polymerase encoded by the virus

Which scientist first discovered prions? A. Dimitri Ivanovski B. Edward Jenner C. HenriettaLacks D. Stanley Prusiner

D. Stanley Prusiner

The liquid portion of blood that does not contain clotting factors is known as which of the following? A. erythrocytes B. plasma C. platelets D. serum

D. serum

The Baltimore Classification system describes viruses according to which characteristic? A. capsid shape B. host-cellsusceptibility C. the presence or absence of an envelope D. the viral genome

D. the viral genome

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? A. provirus B. virion C. viroid D. virusoid

D. virusoid

T/F A zoonosis can only be transmitted from animals to humans.

False

T/F Any virus can infect any host cell.

False

T/F Prion diseases cannot be transmitted from one generation to the next.

False

T/F The hemagglutinin assay can only identify infectious virus particles.

False

T/F There is a cure for transmissible spongiform encephalopathies.

False

T/F Viruses are facultative intracellular pathogens.

False

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

Generalized transduction

What are the two spike proteins of influenza virus?

Hemagglutinin and neuraminidase.

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

Naked viruses do not have lipid envelopes (only a protein capsid), so it cannot fuse with the host-cell membrane; rather, it enters via receptor-mediated endocytosis.

_____ is an enzyme used by retroviruses to produce complementary DNA from RNA

Reverse transcriptase

Herpesviridae

cold sores and/or genital warts

How is kuru transmitted? A. bloodborne transmission B. contaminated neurosurgical instruments C. eating contaminated cattle meat D. eating infected meat through cannibalism

eating infected meat through cannibalism

Picornaviridae

hepatitis

dsDNA envelope

hepatovirus

(+)ssRNA naked

herpes simplex virus

The lipid content of an enveloped virus is produced from the ____

host cell

dsDNA naked

influenza virus

Hemagglutinin

isolating antibodies from a patient, adding them to a virus, and seeing if the virus can clump erythrocytes

RT-PCR

making cDNA from RNA

Papillomaviridae

penile and/or cervical cancer

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

plaque

All viruses are composed of ________ and ________

protein and nucleic acid

The integrated genome of a retrovirus in a host cell is known as ____

provirus

(+)ssRNA enveloped

reovirus

Parvoviridae

respiratory tract infections

Define the term "tissue tropism."

Viruses can only infect certain types of cells.

PCR

using primers to amplify DNA

The protein content of an enveloped virus is produced from the ____

viral genome

The number of virions per unit volume is known as the _____

viral titer

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

A provirus is the integrated genome from a retrovirus, whereas a prophage is the integrated genome from a bacteriophage.

Which of the following is the host-cell receptor that recognizes human immunodeficiency virus (HIV)? A. CD4 B. CD8 C. Gp120 D. sialic acid

A. CD4

Which method cannot be used to detect virus in a patient's serum? A. EIA B. hemagglutinin assay C. growth in pure culture D. RT-PCR

C. growth in pure culture

Which effect does tomato planta macho viroids have on the crop? A. browning of fruit B. crown-gallformation C. loss of chlorophyll D. lysis of root cells

C. loss of chlorophyll

Which unit of length best describes the average size of a virion? A. mm B. μm C. nm D. pm

C. nm

Transmissible spongiform encephalopathies, such as Creutzfeldt-Jakob disease, are caused by which of the following? A. bacterium B. fungus C. prion D. virus

C. prion

Which of the following is a novel enzyme found in retroviruses? A. forward transcriptase B. retrotranscriptase C. reverse transcriptase D. Taq polymerase

C. reverse transcriptase

Chicken pox can reemerge as which disease? A. cowpox B. genitalwarts C. shingles D. smallpox

C. shingles

Which mechanism of horizontal gene transfer relies on the use of viruses? A. conjugation B. mutation C. transduction D. transformation

C. transduction

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? A. satellite RNA B. virion C. viroid D. virusoid

C. viroid

(−)ssRNA enveloped

HIV

Name two possible shapes for viral capsids.

Helical and polyhedral

EIA

using antibodies to detect viral antigens (proteins)

Which statement regarding the introduction of virus in eggs is true? A. Pox can form on the embryo. B. The virus cannot be introduced into the yolk sac. C. The virus will not kill the embryo if it is introduced early in development. D. Virus introduction will not disrupt embryonic development.

A. Pox can form on the embryo.

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? A. The test result suggests you may have been exposed to the virus, and your serum contains antibodies against the virus. B. The test result suggests you may have been exposed to the virus, but your serum does not contain antibodies against the virus. C. The test result suggests you may not have been exposed to the virus. D. You cannot make a conclusion from the information given.

A. The test result suggests you may have been exposed to the virus, and your serum contains antibodies against the virus.

Arthropods typically serve as which mechanism of transmission for viruses? A. biological vector B. fomite C. mechanicalvector D. both as fomites and as vectors

A. biological vector

Reverse transcriptase is used to generate which nucleic acid from RNA? A. cDNA B. dsRNA C. (+)ssRNA D. (−)ssRNA

A. cDNA

The excision of the viral genome from the host chromosome is known as which of the following? A. induction B. lysogeny C. phageconversion D. transduction

A. induction

9. In the lysogenic cycle of bacteriophages, the integrated phage genome is known as which of the following? A. prophage B. provirus C. virioid D. virion

A. prophage

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

Receptor-mediated endocytosis or membrane fusion

Viruses that infect bacterial cells are known as ____

bacteriophages

T/F (+)ssRNA can be directly used in translation at the ribosome.

True

T/F Most plant viruses do not kill their host.

True

T/F RT-PCR relies on an enzyme encoded by retroviruses.

True

T/F Satellite RNAs can encode for protein.

True

Which of the following is the scientist responsible for first discovering viruses (specifically, tobacco mosaic virus)? A. Dimitri Ivanovski B. Edward Jenner C. HenriettaLacks D. Stanley Prusiner

A. Dimitri Ivanovski

Which of the following is not a property of a virus? A. It is an infectious cellular pathogen. B. It is an obligate intracellular pathogen. C. Its genome consists of DNA or RNA. D. Its genome is surrounded by a protein capsid.

A. It is an infectious cellular pathogen.

8. Which of the following properly lists (in order) the steps of viral replication? A. Attachment → Lysis → Penetration → Biosynthesis → Maturation B. Attachment → Penetration → Biosynthesis → Maturation → Lysis C. Biosynthesis → Attachment → Penetration → Lysis → Maturation D. Penetration → Biosynthesis → Lysis → Attachment → Maturation

B. Attachment → Penetration → Biosynthesis → Maturation → Lysis

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? A. The lysogenic cycle, reactivating as the lytic cycle, followed by generalized transduction B. The lysogenic cycle, reactivating as the lytic cycle, followed by specialized transduction C. The lytic cycle, reactivating as the lysogenic cycle, followed by generalized transduction D. The lytic cycle, reactivating as the lysogenic cycle, followed by specialized transduction

B. The lysogenic cycle, reactivating as the lytic cycle, followed by specialized transduction

The protein subunits that surround the nucleic acid of a virus are known as which of the following? A. amino acids B. capsomeres C. chromatins D. telomeres

B. capsomeres

Viruses can be visualized using which method? A. compound light microscope B. electron microscope C. the naked eye D. ultraviolet rays

B. electron microscope

In retroviruses, the integrated phage genome is known as which of the following? A. prophage B. provirus C. virioid D. virion

B. provirus

Which of the following viruses does not cause latent infections? A. adenovirus B. Epstein-Barr virus C. herpes simplex virus D. varicella-zoster virus

adenovirus