Question 1

Which viruses have single-stranded RNA that acts as a template for DNA synthesis?

Accepted Answer

A) lytic phages 
B) proviruses 
C) viroids 
D) bacteriophages 
E) retroviruses 
A) lytic phages 
B) proviruses 
C) viroids 
D) bacteriophages 
E) retroviruses E

Question 2

If a viral host cell has a mutation that interferes with the addition of carbohydrates to proteins in the Golgi,which of the following could likely result?

Accepted Answer

A) The viral envelope proteins would not be glycosylated and might not arrive at the host plasma membrane. 
B) The viral capsid proteins would not be glycosylated and might not arrive at the host plasma membrane. 
C) The viral core proteins would not be glycosylated and might not arrive at the host plasma membrane. 
D) The virus would be unable to reproduce within the host cell. 
E) There would be no impact on the virus. 
A) The viral envelope proteins would not be glycosylated and might not arrive at the host plasma membrane. 
B) The viral capsid proteins would not be glycosylated and might not arrive at the host plasma membrane. 
C) The viral core proteins would not be glycosylated and might not arrive at the host plasma membrane. 
D) The virus would be unable to reproduce within the host cell. 
E) There would be no impact on the virus. A

Question 3

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
-Which treatment could definitively determine whether or not the component is a viroid?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) first II and then III 
A) I 
B) II 
C) III 
D) IV 
E) first II and then III A

Question 4

Which of the following describes plant virus infections?

Accepted Answer

A) They can be controlled by the use of antibiotics. 
B) They are spread via the plasmodesmata. 
C) They have little effect on plant growth. 
D) They are seldom spread by insects. 
E) They can never be passed vertically. 
A) They can be controlled by the use of antibiotics. 
B) They are spread via the plasmodesmata. 
C) They have little effect on plant growth. 
D) They are seldom spread by insects. 
E) They can never be passed vertically.

Question 5

Which of the following can be effective in preventing the onset of viral infection in humans?

Accepted Answer

A) taking vitamins 
B) getting vaccinated 
C) taking antibiotics 
D) applying antiseptics 
E) taking nucleoside analogues that inhibit transcription 
A) taking vitamins 
B) getting vaccinated 
C) taking antibiotics 
D) applying antiseptics 
E) taking nucleoside analogues that inhibit transcription

Question 6

Which of the following statements describes the lysogenic cycle of lambda (λ)phage?

Accepted Answer

A) After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. 
B) Most of the prophage genes are activated by the product of a particular prophage gene. 
C) The phage genome replicates along with the host genome. 
D) Certain environmental triggers can cause the phage to exit the host genome, switching from the lytic to the lysogenic. 
E) The phage DNA is incorporated by crossing over into any nonspecific site on the host cell's DNA. 
A) After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. 
B) Most of the prophage genes are activated by the product of a particular prophage gene. 
C) The phage genome replicates along with the host genome. 
D) Certain environmental triggers can cause the phage to exit the host genome, switching from the lytic to the lysogenic. 
E) The phage DNA is incorporated by crossing over into any nonspecific site on the host cell's DNA.

Question 7

A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV).The cell contents are left in a covered test tube overnight.The next day this mixture is sprayed on tobacco plants.Which of the following would be expected to occur?

Accepted Answer

A) The plants would develop some but not all of the symptoms of the TMV infection. 
B) The plants would develop symptoms typically produced by viroids. 
C) The plants would develop the typical symptoms of TMV infection. 
D) The plants would not show any disease symptoms. 
E) The plants would become infected, but the sap from these plants would be unable to infect other plants. 
A) The plants would develop some but not all of the symptoms of the TMV infection. 
B) The plants would develop symptoms typically produced by viroids. 
C) The plants would develop the typical symptoms of TMV infection. 
D) The plants would not show any disease symptoms. 
E) The plants would become infected, but the sap from these plants would be unable to infect other plants.

Question 8

H1N1 was declared ________ in June 2009.

Accepted Answer

A) an epidemic 
B) a pandemic 
C) cured 
D) under control 
E) non-life-threatening 
A) an epidemic 
B) a pandemic 
C) cured 
D) under control 
E) non-life-threatening

Question 9

Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host?

Accepted Answer

A) It is able to spread to a large number of new hosts quickly because the new hosts have no immunological memory of them. 
B) The new virus replicates quickly and undergoes rapid adaptation to a series of divergent hosts. 
C) A change in environmental conditions such as weather patterns quickly forces the new virus to invade new areas. 
D) Sporadic outbreaks will be followed almost immediately by a widespread pandemic. 
E) The newly emerging virus will die out rather quickly or will mutate to be far less lethal. 
A) It is able to spread to a large number of new hosts quickly because the new hosts have no immunological memory of them. 
B) The new virus replicates quickly and undergoes rapid adaptation to a series of divergent hosts. 
C) A change in environmental conditions such as weather patterns quickly forces the new virus to invade new areas. 
D) Sporadic outbreaks will be followed almost immediately by a widespread pandemic. 
E) The newly emerging virus will die out rather quickly or will mutate to be far less lethal.

Question 10

HIV is inactivated in the laboratory after a few minutes of sitting at room temperature,but the flu virus is still active after sitting for several hours.What are the practical consequences of these findings?

Accepted Answer

A) HIV can be transmitted more easily from person to person than the flu virus. 
B) The flu virus can be transmitted more easily from person to person than HIV. 
C) This property of HIV makes it more likely to be a pandemic than the flu virus. 
D) Disinfecting surfaces is more important to reduce the spread of HIV than the flu. 
E) This results in HIVs more serious long-term consequences to the host. 
A) HIV can be transmitted more easily from person to person than the flu virus. 
B) The flu virus can be transmitted more easily from person to person than HIV. 
C) This property of HIV makes it more likely to be a pandemic than the flu virus. 
D) Disinfecting surfaces is more important to reduce the spread of HIV than the flu. 
E) This results in HIVs more serious long-term consequences to the host.

Question 11

Use the following information to answer the questions below.
Some viruses can be crystallized and their structures analyzed.One such virus is Desmodium,or yellow mottle virus,which infects beans.This is a member of the tymovirus group and has a single-stranded RNA genome of ~6300 nucleotides.Its virion is 25-30 nm in diameter,and is made up of 180 copies of a single capsid protein that self-associate to form each capsomere,which has icosahedral symmetry with 20 facets.
-If this virus has a positive RNA strand as its genome,it begins the infection by using this strand as mRNA.Therefore,which of the following do you expect to be able to measure?

Accepted Answer

A) replication rate 
B) transcription rate 
C) translation rate 
D) accumulation of new ribosomes 
E) formation of new transcription factors 
A) replication rate 
B) transcription rate 
C) translation rate 
D) accumulation of new ribosomes 
E) formation of new transcription factors

Question 12

Use the following information to answer the few questions.
The herpes viruses are very important enveloped DNA viruses that cause disease in all vertebrate species and in some invertebrates such as oysters.Some of the human ones are herpes simplex (HSV)I and II,causing facial and genital lesions,and the varicella-zoster (VSV),causing chicken pox and shingles.Each of these three actively infect nervous tissue.Primary infections are fairly mild,but the virus is not then cleared from the host; rather,viral genomes are maintained in cells in a latent phase.The virus can then reactivate,replicate again,and be infectious to others.
-In electron micrographs of HSV infection,it can be seen that the intact virus initially reacts with cell surface proteoglycans,then with specific receptors.This is later followed by viral capsids docking with nuclear pores.Afterward,the capsids go from being full to being "empty." Which of the following best fits these observations?

Accepted Answer

A) Viral capsids are needed for the cell to become infected; only the capsids enter the nucleus. 
B) The viral envelope is not required for infectivity, since the envelope does not enter the nucleus. 
C) Only the genetic material of the virus is involved in the cell's infectivity, and is injected like the genome of a phage. 
D) The viral envelope mediates entry into the cell, the capsid entry into the nuclear membrane, and the genome is all that enters the nucleus. 
E) The viral capsid mediates entry into the cell, and only the genomic DNA enters the nucleus, where it may or may not replicate. 
A) Viral capsids are needed for the cell to become infected; only the capsids enter the nucleus. 
B) The viral envelope is not required for infectivity, since the envelope does not enter the nucleus. 
C) Only the genetic material of the virus is involved in the cell's infectivity, and is injected like the genome of a phage. 
D) The viral envelope mediates entry into the cell, the capsid entry into the nuclear membrane, and the genome is all that enters the nucleus. 
E) The viral capsid mediates entry into the cell, and only the genomic DNA enters the nucleus, where it may or may not replicate.

Question 13

Which of the following characteristics,structures,or processes is common to both bacteria and viruses?

Accepted Answer

A) metabolism 
B) ribosomes 
C) genetic material composed of nucleic acid 
D) cell division 
E) independent existence 
A) metabolism 
B) ribosomes 
C) genetic material composed of nucleic acid 
D) cell division 
E) independent existence

Question 14

Use the following information to answer the following questions.
In 1971,David Baltimore described a scheme for classifying viruses based on how the virus produces mRNA.
The table below shows the results of testing five viruses for nuclease specificity,the ability of the virus to act as an mRNA,and presence (+)or absence (-)of its own viral polymerase.
  
-Based on the above table,which virus meets the requirements for a bacteriophage?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 15

Viral disease in plants is spread through the population by

Accepted Answer

A) horizontal transmission (direct infection). 
B) vertical transmission (one generation to the next). 
C) horizontal and vertical transmission. 
D) being in contact with animals harbouring viruses that can jump the species barrier. 
E) There is no viral disease in plants as viruses only attack animals and bacteria. 
A) horizontal transmission (direct infection). 
B) vertical transmission (one generation to the next). 
C) horizontal and vertical transmission. 
D) being in contact with animals harbouring viruses that can jump the species barrier. 
E) There is no viral disease in plants as viruses only attack animals and bacteria.

Question 16

Which of the following supports the argument that viruses are nonliving?

Accepted Answer

A) They are not able to reproduce or carry out metabolism outside of a host cell. 
B) Their DNA does not encode proteins. 
C) They have RNA rather than DNA. 
D) They do not evolve. 
E) They mutate rapidly. 
A) They are not able to reproduce or carry out metabolism outside of a host cell. 
B) Their DNA does not encode proteins. 
C) They have RNA rather than DNA. 
D) They do not evolve. 
E) They mutate rapidly.

Question 17

Use the following information to answer the few questions.
The herpes viruses are very important enveloped DNA viruses that cause disease in all vertebrate species and in some invertebrates such as oysters.Some of the human ones are herpes simplex (HSV)I and II,causing facial and genital lesions,and the varicella-zoster (VSV),causing chicken pox and shingles.Each of these three actively infect nervous tissue.Primary infections are fairly mild,but the virus is not then cleared from the host; rather,viral genomes are maintained in cells in a latent phase.The virus can then reactivate,replicate again,and be infectious to others.
-If scientists are trying to use what they know about HSV to devise a means of protecting other people from being infected,which of the following would have the best chance of lowering the number of new cases of infection?

Accepted Answer

A) vaccination of all persons with preexisting cases 
B) interference with new viral replication in preexisting cases 
C) treatment of the HSV lesions to shorten the breakout 
D) medication that destroys surface HSV before it gets to neurons 
E) education about avoiding sources of infection 
A) vaccination of all persons with preexisting cases 
B) interference with new viral replication in preexisting cases 
C) treatment of the HSV lesions to shorten the breakout 
D) medication that destroys surface HSV before it gets to neurons 
E) education about avoiding sources of infection

Question 18

What are prions?

Accepted Answer

A) mobile segments of DNA 
B) tiny molecules of RNA that infect plants 
C) viral DNA that has had to attach itself to the host genome 
D) misfolded versions of normal brain protein 
E) viruses that invade bacteria 
A) mobile segments of DNA 
B) tiny molecules of RNA that infect plants 
C) viral DNA that has had to attach itself to the host genome 
D) misfolded versions of normal brain protein 
E) viruses that invade bacteria

Question 19

Use the figure that follows to answer the questions below.
  
-Which of the three types of viruses shown above would you expect to include a capsid(s)?

Accepted Answer

A) I only 
B) II only 
C) III only 
D) I and II only 
E) all three 
A) I only 
B) II only 
C) III only 
D) I and II only 
E) all three

Question 20

Most molecular biologists think that viruses originated from fragments of cellular nucleic acid.Which of the following observations supports this theory?

Accepted Answer

A) Viruses contain either DNA or RNA. 
B) Viruses are enclosed in protein capsids rather than plasma membranes. 
C) Viruses can reproduce only inside host cells. 
D) Viruses can infect both prokaryotic and eukaryotic cells. 
E) Viral genomes are usually similar to the genome of the host cell. 
A) Viruses contain either DNA or RNA. 
B) Viruses are enclosed in protein capsids rather than plasma membranes. 
C) Viruses can reproduce only inside host cells. 
D) Viruses can infect both prokaryotic and eukaryotic cells. 
E) Viral genomes are usually similar to the genome of the host cell.

Exam 19: Viruses

Which viruses have single-stranded RNA that acts as a template for DNA synthesis?

If a viral host cell has a mutation that interferes with the addition of carbohydrates to proteins in the Golgi,which of the following could likely result?

Which of the following describes plant virus infections?

Which of the following can be effective in preventing the onset of viral infection in humans?

Which of the following statements describes the lysogenic cycle of lambda (λ)phage?

A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV).The cell contents are left in a covered test tube overnight.The next day this mixture is sprayed on tobacco plants.Which of the following would be expected to occur?

H1N1 was declared ________ in June 2009.

Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host?

HIV is inactivated in the laboratory after a few minutes of sitting at room temperature,but the flu virus is still active after sitting for several hours.What are the practical consequences of these findings?

Which of the following characteristics,structures,or processes is common to both bacteria and viruses?

Viral disease in plants is spread through the population by

Which of the following supports the argument that viruses are nonliving?

What are prions?

Use the figure that follows to answer the questions below. -Which of the three types of viruses shown above would you expect to include a capsid(s)?

Most molecular biologists think that viruses originated from fragments of cellular nucleic acid.Which of the following observations supports this theory?

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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