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21 Cards in this Set

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  • Back
Wendell Stanley helped influence the development of virology by suggesting that the agent infecting tobacco leaves might be
A. chemicals rather than primitive cells.
B. larger than most bacteria.
C. caused by a crystallized life-form.
D. a living organism composed of nucleic acid and a protein coat.
A. chemicals rather than primitive cells.
Which of the following statements does not provide a valid comparison between viruses and cells?
A. A virus cannot grow, achieve homeostasis, or metabolize, but a cell can.
B. A virus cannot mutate, but a cell can.
C. A virus can replicate only within a host cell, while cells can replicate independently by cell division.
D. Both viruses and cells can have DNA.
B. A virus cannot mutate, but a cell can.
A virus’s structural features could include a(n)
A. envelope.
B. capsid.
C. dRNA genome.
D. All of the above
D. All of the above -All viruses have a nucleic acid consisting of either DNA or RNA and a protein coat, called a capsid, surrounding the nucleic acid. Some viruses also have an envelope.
A virus’s shape is determined by
A. the shape of its capsid.
B. its organelles.
C. its glycoprotein.
D. its envelope.
A. the shape of its capsid.
Which of the following statements is false?
A. Viruses can be grouped as either RNA viruses or DNA viruses.
B. Viruses can be grouped based on whether their nucleic acid is single-stranded or double-stranded.
C. Viruses can be classified based on evolutionary relationships.
D. Scientists group viruses by shape and structure.
C. Viruses can be classified based on evolutionary relationships.
Which of the following is not an example of how a virus might be grouped?
A. helical, enveloped
B. helical, Gram-positive
C. icosahedral, non-enveloped
D. complex brick-shaped, enveloped
B. helical, Gram-positive
Viruses are called obligate intracellular parasites because they
A. replicate in the material between cells.
B. feed on cells from the inside out.
C. need a host cell to replicate.
D. must live inside cells.
C. need a host cell to replicate.
How is a bacteriophage different from viruses that cause colds?
A. Bacteriophages infect bacteria.
B. Bacteriophages have a unique replication cycle.
C. Bacteriophages contain a nucleic acid.
D. Bacteriophages have a unique shape.
A. Bacteriophages infect bacteria.
Which of the following phases are not part of the lytic cycle?
A. attachment and entry
B. integration and cell multiplication
C. replication and assembly
D. lysis and release
B. integration and cell multiplication
How is the lytic cycle different from the lysogenic cycle?
A. In the lytic cycle, a virus's genes are copied each time the cell divides. In the lysogenic cycle, new viruses burst out of the cell.
B. In the lytic cycle, viruses begin to replicate immediately. In the lysogenic cycle, viral genes may remain inactive for long periods of time.
C. In the lytic cycle, the host cell is preserved. In the lysogenic cycle, the host cell is destroyed.
D. The lytic cycle relates to the reproduction of viruses, and the lysogenic cycle relates to the reproduction of bacteria.
B. In the lytic cycle, viruses begin to replicate immediately. In the lysogenic cycle, viral genes may remain inactive for long periods of time.
Which of the following comparisons between a virulent virus and a temperate virus is true?
A. Virulent viruses kill their host cells immediately, while temperate viruses do not.
B. Virulent viruses and temperate viruses replicate in the same way.
C. Temperate viruses enter cells by fusing with them, while virulent viruses inject viral DNA into cells.
D. Temperate viruses are mildly active viruses that are not capable of doing much damage to the host cell; virulent viruses are deadly.
A. Virulent viruses kill their host cells immediately, while temperate viruses do not.
Which of the following best describes a provirus?
A. an intracellular bacteriophage that is harmless to the host cell
B. a viral DNA molecule produced by reverse transcriptase
C. budding viral particles
D. part of a cell membrane used for the construction of a viral envelope
B. a viral DNA molecule produced by reverse transcriptase
Which of the following statements about viral evolution is false?
A. Viruses probably evolved from early cells.
B. Early simple viruses probably evolved genes that allowed them to invade healthy cells.
C. The first viruses were probably able to travel through damaged cell membranes.
D. Viruses probably evolved from bacteria that are immune to antibiotics.
D. Viruses probably evolved from bacteria that are immune to antibiotics.
Which of the following diseases is not caused by a virus?
A. the common cold
B. the flu
C. AIDS
D. scarlet fever
D. scarlet fever
Chickenpox is related to which of the following viruses?
A. shingles
B. cowpox
C. smallpox
D. hepatitis
A. shingles
What is the most effective weapon for fighting the spread of viral diseases?
A. antibiotics
B. antiviral drugs
C. vaccines
D. plenty of sleep and fluids
C. vaccines
Some vaccines consist of inactivated or attenuated viruses. Which of the following statements about inactivated and attenuated viruses is true?
A. Inactivated viruses have been temporarily inactivated, and attenuated viruses do not replicate in a host.
B. Inactivated viruses do not replicate in a host, and attenuated viruses have been genetically altered so that they cannot cause disease.
C. Inactivated viruses have been genetically altered so that they cannot cause disease, and attenuated viruses have been temporarily inactivated.
D. Inactivated viruses will not cause disease, but attenuated viruses will.
B. Inactivated viruses do not replicate in a host, and attenuated viruses have been genetically altered so that they cannot cause disease.
Which of the following statements is false?
A. No naturally acquired cases of smallpox have been recorded in more than two decades.
B. Smallpox once killed 40 percent of all people infected.
C. Smallpox is a DNA virus transmitted by nasal droplets.
D. The genetic diversity and mutability of the smallpox virus have made developing a vaccine difficult; however, educating people has proven effective in slowing the disease.
D. The genetic diversity and mutability of the smallpox virus have made developing a vaccine difficult; however, educating people has proven effective in slowing the disease
Which of the following is not a purpose of antiviral agents?
A. to interfere with the synthesis of nucleic acids
B. to interfere with the synthesis of viral capsids
C. to work with antibiotics to destroy bacteria that viruses have invaded
D. to increase the time a temperate virus remains in the lysogenic cycle.
C. to work with antibiotics to destroy bacteria that viruses have invaded
Today, new viruses that affect humans may emerge from
A. recently cleared forests.
B. isolated habitats.
C. virus-infected animals.
D. All of the above
D. All of the above
Which of the following viruses is linked to cancer?
A. hepatitis B
B. chickenpox
C. influenza
D. rabies
A. hepatitis B