BISC 261 Exam with Questions with 100%
Correct Answers
Which of the following can be used to cultivate plant viruses? - Answer All of these can
be used to cultivate plant viruses.
Cultures of separated plant cells.B. Whole plants.C. Plant protoplast cultures.D.
0.2 mls of a 10-4 dilution of a virus preparation yields 90 plaques. What is the number
of PFU per ml in the undiluted virus preparation? - Answer 4.5 × 106
Hemagglutination is - Answer the clumping together of red blood cells in the
presence of a viral suspension.
Like bacteria and eukaryotic microorganisms, most viruses can be cultured using
artificial media. - Answer FALSE
Bacterial viruses are so named because they have prokaryotic cell structures similar
to their bacterial hosts. - Answer FALSE
Localized areas of destruction occurring on plants that have been infected by a virus are
referred to as __________ lesions. - Answer necrotic
,Which of the following is not a mechanism by which viruses cause cancer - Answer
They produce defective interfering particles.
Which of the following is not true regarding the human hepatitis D virusoid? - Answer D.
All of the statements are true.
Its genome is a circular, single-stranded RNA molecule.B. It needs a helper virus to
infect host cells.C. It produces one protein called the delta antigen.
Which of the following is not true of viroids? - Answer Extracellular viroids have a
lipid bilayer envelope.
Viroids are of economic significance because they cause disease in - Answer plants
Viroids are: - Answer short infectious single stranded RNAs that can infect some plants.
Prions are of significance because they cause infections of - Answer domestic
animals and humans.
Which of the following diseases is (are) caused by prions - Answer All of the choices.
Scrapie.B. Mad cow disease.C. Kuru and Creutzfeldt-Jakob Disease.
Prions consist of proteins and have no apparent nucleic acid genome. - Answer TRUE
Available evidence is consistent with the proposal that prion diseases are caused
by infectious proteins. - Answer TRUE
, The mechanism of pathogenesis by prions may involve a conformational change in
the prion protein (PrP) to an abnormal form. - Answer TRUE
There are no known human diseases that have been linked to prions. - Answer FALSE
Viruses have typical cellular structure like other living organisms. - Answer FALSE
Viruses in the extracellular state possess few, if any, active enzymes. - Answer TRUE
Which is not true of viruses? - Answer They infect animal and plant cells only.
Which of the following is true of viruses in the extracellular phase? - Answer
They behave as a macromolecular complex and are no more alive than are
ribosomes.
A complete virus particle is called a - Answer virion
The nucleic acids carried by viruses usually consist of - Answer either DNA or RNA.
Which of the following is not true of viruses? - Answer Viruses replicate by binary fission
Viruses infecting protists, including algae, have never been detected. - Answer FALSE
One way in which small viruses package more information into a very small genome is
to use overlapping genes so that the same base sequence is read in more than one
reading frame. - Answer TRUE
Almost all known plant viruses are RNA viruses. - Answer TRUE
Correct Answers
Which of the following can be used to cultivate plant viruses? - Answer All of these can
be used to cultivate plant viruses.
Cultures of separated plant cells.B. Whole plants.C. Plant protoplast cultures.D.
0.2 mls of a 10-4 dilution of a virus preparation yields 90 plaques. What is the number
of PFU per ml in the undiluted virus preparation? - Answer 4.5 × 106
Hemagglutination is - Answer the clumping together of red blood cells in the
presence of a viral suspension.
Like bacteria and eukaryotic microorganisms, most viruses can be cultured using
artificial media. - Answer FALSE
Bacterial viruses are so named because they have prokaryotic cell structures similar
to their bacterial hosts. - Answer FALSE
Localized areas of destruction occurring on plants that have been infected by a virus are
referred to as __________ lesions. - Answer necrotic
,Which of the following is not a mechanism by which viruses cause cancer - Answer
They produce defective interfering particles.
Which of the following is not true regarding the human hepatitis D virusoid? - Answer D.
All of the statements are true.
Its genome is a circular, single-stranded RNA molecule.B. It needs a helper virus to
infect host cells.C. It produces one protein called the delta antigen.
Which of the following is not true of viroids? - Answer Extracellular viroids have a
lipid bilayer envelope.
Viroids are of economic significance because they cause disease in - Answer plants
Viroids are: - Answer short infectious single stranded RNAs that can infect some plants.
Prions are of significance because they cause infections of - Answer domestic
animals and humans.
Which of the following diseases is (are) caused by prions - Answer All of the choices.
Scrapie.B. Mad cow disease.C. Kuru and Creutzfeldt-Jakob Disease.
Prions consist of proteins and have no apparent nucleic acid genome. - Answer TRUE
Available evidence is consistent with the proposal that prion diseases are caused
by infectious proteins. - Answer TRUE
, The mechanism of pathogenesis by prions may involve a conformational change in
the prion protein (PrP) to an abnormal form. - Answer TRUE
There are no known human diseases that have been linked to prions. - Answer FALSE
Viruses have typical cellular structure like other living organisms. - Answer FALSE
Viruses in the extracellular state possess few, if any, active enzymes. - Answer TRUE
Which is not true of viruses? - Answer They infect animal and plant cells only.
Which of the following is true of viruses in the extracellular phase? - Answer
They behave as a macromolecular complex and are no more alive than are
ribosomes.
A complete virus particle is called a - Answer virion
The nucleic acids carried by viruses usually consist of - Answer either DNA or RNA.
Which of the following is not true of viruses? - Answer Viruses replicate by binary fission
Viruses infecting protists, including algae, have never been detected. - Answer FALSE
One way in which small viruses package more information into a very small genome is
to use overlapping genes so that the same base sequence is read in more than one
reading frame. - Answer TRUE
Almost all known plant viruses are RNA viruses. - Answer TRUE
