Viruses, Viroids and Prions
Viruses lack all of the following EXCEPT:
A. nucleic acid.
B. cytosol.
C. a cytoplasmic membrane.
D. organelles.
Which of the following terms refers to a virus in the extracellular state?
A. nucleocapsid
B. bacteriophage
C. virion
D. capsid
The first virus to be identified was isolated from a
A. fungus.
B. plant.
C. bacterium.
D. human.
The protein coat of a virus is composed of subunits called
A. icosahedra.
B. capsomeres.
C. envelopes.
D. capsids.
All of the following terms refer to viral shapes EXCEPT:
A. polyhedral.
B. complex.
C. helical.
D. prion.
Why do viruses have to infect host cells?
A. They cannot survive outside a host cell.
B. They infect host cells in order to steal the cell's genome.
C. They are dependent on host cell organelles and enzymes for their replication.
D. They infect host cells in order to cause tumors.
The tail fibers of a bacteriophage are associated most closely with which of the following stages of the
lytic replication cycle?
A. assembly
B. synthesis
C. entry
D. attachment
Which of the following viruses exhibits a lysogenic replication cycle?
A. influenza virus
B. HIV
C. T4
D. lambda
Which of the following viruses creates a DNA intermediary molecule transcribed from their RNA
genomes?
A. retroviruses
B. positive-sense ssRNA
C. negative-sense ssRNA
D. dsDNA
Which of the following groups of viruses is replicated in the cell's nucleus?
A. dsDNA viruses
B. negative-sense ssRNA viruses
C. positive-sense ssRNA viruses
D. dsRNA viruses
Negative-sense ssRNA viruses require which of the following enzymes for their replication?
A. DNA polymerase
B. reverse transcriptase
C. lysozyme
D. RNA-dependent RNA transcriptase
Bacteriophages can use all of the following structures for attachment to a bacterial cell EXCEPT:
A. the cell wall.
B. pili.
C. the cytoplasmic membrane.
D. flagella.
A naked virus is one without
A. a capsid.
B. an envelope.
C. capsomeres.
D. a genome.
All of the following are common features of bacteriophage and animal virus infections EXCEPT:
A. uncoating.
B. assembly.
C. penetration.
D. attachment.
What is the advantage of lysogeny to lambda phage?
A. The genome of the phage is replicated much faster.
B. Other phages infect the same cell and recombine with lambda phage.
C. The host cell is destroyed more easily.
D. The phage persists for generations in the bacterial chromosome.
The first evidence that viruses can cause some animal cancers was provided by
A. d'Herelle
B. Ivanowsky.
C. Prusiner.
D. Rous.
Viruses can be cultured in the laboratory using all of the following EXCEPT:
A. agar plates.
B. embryonated eggs.
C. cell cultures.
D. whole organisms.
HeLa cells are an example of a(n)
A. continuous cell culture.
B. diploid cell culture.
C. plaque.
D. tumor.
Which of the following types of genetic material is normally found only in certain types of viruses?
A. dsDNA
B. ssRNA
C. dsRNA
D. None of these is limited to viruses.
Prions are infectious because of which of the following phenomena?
A. induction
B. protein folding
C. metastasis
D. latency