Chapter 21

Which statement is true of viral replication? Select one: a. The viral capsid helps the host cell produce more copies of the viral genome. b. During attachment, the virus attaches at specific sites on the cell surface. c. In the process of apoptosis, the cell survives. d. mRNA works outside of the host cell to produce enzymes and proteins.

During attachment, the virus attaches at specific sites on the cell surface.

Which is true of DNA viruses? Select one: a. They use the host cell's machinery to produce new copies of their genome. b. They are the only kind of viruses that can cause cancer. c. They all have envelopes. d. They are not important plant pathogens.

They use the host cell's machinery to produce new copies of their genome.

Which of the following statements about virus structure is true? Select one: a. DNA is the genetic material in all viruses. b. All viruses are encased in a viral membrane. c. The capsomere is made up of small protein subunits called capsids. d. Glycoproteins help the virus attach to the host cell.

Glycoproteins help the virus attach to the host cell.

Which statement is true of reverse transcriptase? Select one: a. It is a nucleic acid. b. It infects cells. c. It is a lipid. d. It transcribes RNA to make DNA.

It transcribes RNA to make DNA

Oncogenic virus cores can be __________. Select one: a. RNA b. DNA c. neither RNA nor DNA d. either RNA or DNA

either RNA or DNA

A patient presents at the clinic with an acute viral infection. Assays that analyze the viral life cycle classify the virus into Group V with a segmented genome. Which virus is the most likely diagnosis for the patient? Select one: a. influenza A virus b. rabies virus c. picornavirus d. HIV-1

influenza A virus

A scientist discovers a new virus with a linear, RNA genome surrounded by a helical capsid. The virus is most likely a member of which family based on structure classification? Select one: a. retroviruses b. herpes viruses c. influenza viruses d. rabies virus

rabies virus

The observation that the bacteria genus Chlamydia contains species that can only survive as intracellular parasites supports which viral origin hypothesis? Select one: a. self-replicating b. virus-first c. regressive d. progressive

regressive

Vaccines ____________. Select one: a. are only needed once b. kill viruses c. stimulate an immune response d. are similar to viroids

stimulate an immune response

Which statement is true? Select one: a. Most viruses are easily visualized with a light microscope. b. Viruses are acellular. c. Viruses replicate outside of the cell. d. A virion contains DNA and RNA.

Viruses are acellular.

Which of the following is NOT used to treat active viral disease? Select one: a. antibiotics b. anti-viral drugs c. phage therapy d. vaccines

antibiotics

People with the CCR5Δ32 mutation of a T-cell surface protein can be exposed to some strains of HIV-1 without becoming sick. What step of the virus life cycle is likely to be inhibited with this mutation? Select one: a. release b. reverse transcription c. attachment d. uncoating

attachment

Viruses _____________. Select one: a. vary in shape b. cannot have a long shape c. all have a round shape d. do not maintain any shape

vary in shape

Which statement is NOT true of viral replication? Select one: a. Newly released virions can infect adjacent cells. b. There are six basic steps in the viral replication cycle. c. Viral replication does not affect host cell function. d. A lysogenic cycle kills the host cell.

A lysogenic cycle kills the host cell.

Which of the following statements is false? Select one: a. In the lysogenic cycle, phage DNA is incorporated into the host genome. b. Cell lysis only occurs in the lytic cycle. c. An environmental stressor can cause the phage to initiate the lysogenic cycle. d. In the lytic cycle, new phages are produced and released into the environment.

An environmental stressor can cause the phage to initiate the lysogenic cycle.

Which of the following is not associated with prions? Select one: a. DNA b. Mad cow disease c. toxic proteins d. replicating shapes

DNA

An apple grower notices that several of his apple trees with fungi growing on their trunks have developed necrotic ring spots, while other trees in the orchard that lack fungi appear healthy. What is the most likely conclusion the farmer can make about the virus infecting his apple trees? Select one: a. The fungi attract disease-carrying insects. b. The fungi carry disease. c. The apple trees were infected by vertical transmission. d. The apple trees were infected by horizontal transmission.

The apple trees were infected by horizontal transmission.

Which statement is true of viroids? Select one: a. They produce proteins. b. They affect both plants and animals. c. They are single-stranded RNA particles. d. They reproduce only outside of the cell.

They are single-stranded RNA particles.

A bacteriophage can infect ______________. Select one: a. the lungs b. bacteria c. viruses d. prions

bacteria

The viral ________ play(s) a role in attaching a virion to the host cell. a. core b. capsid c. envelope d. both b and c

both b and c