Question 1

Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations?

Accepted Answer

A) The high mutation rate due to lack of proofreading of RNA genome replication errors. 
B) Transcription from the host cell RNA polymerase introduces numerous mutations. 
C) Capsid proteins from the host cell can replace the viral capsid. 
D) Viral RNA is translated by host cell ribosomes. 
E) Recombination between viral and host DNA. 
A) The high mutation rate due to lack of proofreading of RNA genome replication errors. 
B) Transcription from the host cell RNA polymerase introduces numerous mutations. 
C) Capsid proteins from the host cell can replace the viral capsid. 
D) Viral RNA is translated by host cell ribosomes. 
E) Recombination between viral and host DNA.

Question 2

Use the following figure to answer the questions below.
  
-In the figure,when new viruses are being assembled (IV),what mediates the assembly?

Accepted Answer

A) host cell chaperones 
B) assembly proteins coded for by the host nucleus 
C) assembly proteins coded for by the viral genes 
D) viral RNA intermediates 
E) Nothing; they self-assemble. 
A) host cell chaperones 
B) assembly proteins coded for by the host nucleus 
C) assembly proteins coded for by the viral genes 
D) viral RNA intermediates 
E) Nothing; they self-assemble.

Question 3

Emerging viruses arise by

Accepted Answer

A) mutation of existing viruses. 
B) the spread of existing viruses to new host species. 
C) the spread of existing viruses more widely within their host species. 
D) mutation of existing viruses, the spread of existing viruses to new host species, and the spread of existing viruses more widely within their host species. 
E) none of these. 
A) mutation of existing viruses. 
B) the spread of existing viruses to new host species. 
C) the spread of existing viruses more widely within their host species. 
D) mutation of existing viruses, the spread of existing viruses to new host species, and the spread of existing viruses more widely within their host species. 
E) none of these.

Question 4

Why do scientists consider HIV to be an emerging virus?

Accepted Answer

A) HIV infected humans long before the 1980s, but it has now mutated to a more deadly form. 
B) HIV mutates rapidly making the virus very different from HIV in the early 1980s. 
C) HIV suddenly became apparent and widespread in the 1980s. 
D) HIV is now starting to cause diseases other than AIDS, such as rare types of cancers and pneumonias. 
E) To infect, HIV originally required other concurrent viral infections in the host, however, now HIV can infect humans in the absence of other concurrent viral infections. 
A) HIV infected humans long before the 1980s, but it has now mutated to a more deadly form. 
B) HIV mutates rapidly making the virus very different from HIV in the early 1980s. 
C) HIV suddenly became apparent and widespread in the 1980s. 
D) HIV is now starting to cause diseases other than AIDS, such as rare types of cancers and pneumonias. 
E) To infect, HIV originally required other concurrent viral infections in the host, however, now HIV can infect humans in the absence of other concurrent viral infections.

Question 5

To cause a human pandemic,the H5N1 avian flu virus would have to

Accepted Answer

A) spread to primates such as chimpanzees. 
B) develop into a virus with a different host range. 
C) become capable of human-to-human transmission. 
D) arise independently in chickens in North and South America. 
E) become much more pathogenic. 
A) spread to primates such as chimpanzees. 
B) develop into a virus with a different host range. 
C) become capable of human-to-human transmission. 
D) arise independently in chickens in North and South America. 
E) become much more pathogenic.

Question 6

Why do RNA viruses appear to have higher rates of mutation?

Accepted Answer

A) RNA nucleotides are more unstable than DNA nucleotides. 
B) Replication of their genomes does not involve proofreading. 
C) RNA viruses replicate faster. 
D) RNA viruses can incorporate a variety of nonstandard bases. 
E) RNA viruses are more sensitive to mutagens. 
A) RNA nucleotides are more unstable than DNA nucleotides. 
B) Replication of their genomes does not involve proofreading. 
C) RNA viruses replicate faster. 
D) RNA viruses can incorporate a variety of nonstandard bases. 
E) RNA viruses are more sensitive to mutagens.

Question 7

Refer to the treatments listed below to answer the following questions.
You isolate an infectious substance that is capable of causing disease in plants,but you do not know whether the infectious agent is a bacterium,virus,viroid,or prion.You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.
I.treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious
II.filtering the substance to remove all elements smaller than what can be easily seen under a light microscope
III.culturing the substance by itself on nutritive medium,away from any plant cells
IV.treating the sample with proteases that digest all proteins and then determining whether it is still infectious
-If you already knew that the infectious agent was either bacterial or viral,which treatment would allow you to distinguish between these two possibilities?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) either II or IV 
A) I 
B) II 
C) III 
D) IV 
E) either II or IV

Question 8

Use the following figure and information to answer the question(s)below.
   
Cells were infected with approximately 1000 copies of either virus A or virus B at the 0 time point.At five-minute intervals,a sample of the virus and cell mixture was removed.The intact cells were removed from the sample,and the number of viruses per milliliter of culture was determined.
-Using the data in the figure above,how long does it take for virus A to go through one lytic cycle?

Accepted Answer

A) 15 minutes 
B) 30 minutes 
C) 45 minutes 
D) 90 minutes 
E) It is not possible to determine. 
A) 15 minutes 
B) 30 minutes 
C) 45 minutes 
D) 90 minutes 
E) It is not possible to determine.

Question 9

Which of the following viral features is most apt to correlate with the size of the genome?

Accepted Answer

A) size of the viral capsomeres 
B) RNA versus DNA genome 
C) double- versus single-strand genomes 
D) size and shape of the capsid 
E) glycoproteins of the envelope 
A) size of the viral capsomeres 
B) RNA versus DNA genome 
C) double- versus single-strand genomes 
D) size and shape of the capsid 
E) glycoproteins of the envelope

Question 10

Which of the following is true of viruses?

Accepted Answer

A) They manufacture their own ATP, proteins, and nucleic acids. 
B) They use the host cell to copy themselves and make viral proteins. 
C) They use the host cell to copy themselves and then viruses synthesize their own proteins. 
D) They metabolize food and produce their own ATP. 
E) They copy themselves but are unable to make proteins. 
A) They manufacture their own ATP, proteins, and nucleic acids. 
B) They use the host cell to copy themselves and make viral proteins. 
C) They use the host cell to copy themselves and then viruses synthesize their own proteins. 
D) They metabolize food and produce their own ATP. 
E) They copy themselves but are unable to make proteins.

Question 11

Which of the following viruses would most likely have reverse transcriptase?

Accepted Answer

A) an RNA-based lytic virus 
B) an RNA-based lysogenic virus 
C) a DNA-based lytic virus 
D) a DNA-based lysogenic virus 
E) both RNA- and DNA-based lytic viruses 
A) an RNA-based lytic virus 
B) an RNA-based lysogenic virus 
C) a DNA-based lytic virus 
D) a DNA-based lysogenic virus 
E) both RNA- and DNA-based lytic viruses

Exam 19: Viruses

Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations?

Use the following figure to answer the questions below. -In the figure,when new viruses are being assembled (IV),what mediates the assembly?

Emerging viruses arise by

Why do scientists consider HIV to be an emerging virus?

To cause a human pandemic,the H5N1 avian flu virus would have to

Why do RNA viruses appear to have higher rates of mutation?

Which of the following viral features is most apt to correlate with the size of the genome?

Which of the following is true of viruses?

Which of the following viruses would most likely have reverse transcriptase?

Introduction: Evolution and Themes of Biology

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

DNA Tools and Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure,Growth,and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons,Synapses,and Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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