Chapter 6 practice questions

All of the following explain why viral genomes evolve rapidly except: reassortment events cause rapid viral evolution. DNA viruses have a high mutation rate. quick replication time of viruses. RNA viruses have a high mutation rate.

DNA viruses have a high mutation rate.

viral ___________ help viruses attach to and gain entry into host cells

spikes

a _____________ is a single particle made up of genetic material encased in a protein shell

virion

_________________ use host-cell energy and machinery to replicate

viruses

Viral genetic reassortment is most likely to occur when __________.

different viral strains infect the same cell

Which of the following is not a viral genome arrangement? Segmented RNA Double-stranded RNA Segmented DNA Single-stranded DNA

segmented DNA

Which of the following RNA virus families includes the virus that causes dengue fever? Flaviviridae Retroviridae Calciviridae Picornaviridae

Flaviviridae

Which of the following is not a viral genome arrangement?

Circular RNA

Which of the following DNA virus families includes the viruses that cause warts and cervical cancer in humans? Herpesviridae Hepadnaviridae Poxviridae Papillomaviridae

Papillomaviridae

RNA viruses are able to mutate more rapidly than DNA viruses because _______________. RNA polymerases do not have proofreading capabilities segmented RNA viruses are more prone to mutation, unlike DNA viruses DNA viruses do not release as many virions as RNA viruses RNA viruses undergo reassortment more often than DNA viruses

RNA polymerases do not have proofreading capabilities

Which of the following is not used to classify and name viruses? Virus size Capsid symmetry Presence or absence of an envelope Genome architecture

Virus size

Yearly vaccinations for influenza are necessary due to __________.

antigenic drift

***Pandemic outbreaks of influenza are the result of __________.

antigenic shift

Choose the false statement. Single-stranded DNA (ssDNA) viruses use RNA-dependent RNA polymerases to build mRNA. Single-stranded sense RNA (ssRNA+) viruses have genomes that are directly readable as mRNA. Double-stranded DNA (dsDNA) viruses transcribe their genome using host cell RNA polymerases. Double-stranded RNA (dsRNA) viruses rely on viral RNA-dependent RNA polymerases to transcribe viral mRNA.

Single-stranded DNA (ssDNA) viruses use RNA-dependent RNA polymerases to build mRNA.

Which of the following RNA virus families includes the virus that causes polio? Calciviridae Flaviviridae Picornaviridae Retroviridae

Picornaviridae

__________________ may appear spherical, but are three-dimensional polygons

icosahedral viruses

the viral ____________ is often compromised of the host cell membrane

envelope

Which of the following is mismatched? Viruses: Usually viewed with light microscopy. Viruses: Protein capsid with nucleic acid. Eukaryotes: May be viewed with light microscopy. Prokaryotes: Cells without nuclei or membrane-bound organelles.

Viruses: Usually viewed with light microscopy. *VIRUSES CAN ONLY BE VIEWED WITH ELECTRON MICROSCOPY

Frequent mutations in Influenza A change the protein makeup of hemagglutinin (HA) and neuraminidase (NA) __________.

spikes

_____________________ is the result of minor mutations to HA and NA spikes that allow the virus to evade a quick antibody response by making the new strains different enough to go unrecognized by the immune system, which necessitates yearly vaccinations against new strains.

Antigenic drift

Host antibodies against the influenza virus are developed against ___________.

HA and NA spikes

Which of the following DNA virus families includes viruses that cause oral herpes, genital herpes, and chickenpox? Poxviridae Herpesviridae Hepadnaviridae Papillomaviridae

Herpesviridae

Which of the following best describes the genomes of influenza, measles, Ebola, and rabies viruses? They each have an RNA genome that is complementary to mRNA. Their RNA genome functions directly as mRNA. They each have a double-stranded RNA genome that is transcribed to make mRNA. They each have an RNA genome that directs the production of DNA, which is then transcribed into mRNA.

They each have an RNA genome that is complementary to mRNA.

Antigenic drift results from:

minor changes to HA and NA spikes resulting from frequent mutation of the influenza RNA genome.

Retroviruses produce mRNA by: unwinding double-stranded RNA (dsRNA) and then transcribing it into an mRNA format. translating the viral RNA genome as mRNA. using reverse transcriptase to convert single- stranded RNA (ssRNA) to double-stranded DNA (dsDNA) and then using the dsDNA for transcription. using virally encoded RNA-dependent RNA polymerases to build a new RNA from an existing RNA template.

using reverse transcriptase to convert single- stranded RNA (ssRNA) to double-stranded DNA (dsDNA) and then using the dsDNA for transcription.