Question 1

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 2

Which of the following is the best predictor of how much damage a virus causes?

Accepted Answer

A) ability of the infected cell to undergo normal cell division 
B) ability of the infected cell to carry on translation 
C) whether the infected cell produces viral protein 
D) whether the viral mRNA can be transcribed 
E) how much toxin the virus produces 
A) ability of the infected cell to undergo normal cell division 
B) ability of the infected cell to carry on translation 
C) whether the infected cell produces viral protein 
D) whether the viral mRNA can be transcribed 
E) how much toxin the virus produces

Question 3

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 4

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 would you use to determine if the agent is a prion?

Accepted Answer

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

Question 5

A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have

Accepted Answer

A) T2 protein and T4 DNA. 
B) T2 protein and T2 DNA. 
C) a mixture of the DNA and proteins of both phages. 
D) T4 protein and T4 DNA. 
E) T4 protein and T2 DNA. 
A) T2 protein and T4 DNA. 
B) T2 protein and T2 DNA. 
C) a mixture of the DNA and proteins of both phages. 
D) T4 protein and T4 DNA. 
E) T4 protein and T2 DNA.

Question 6

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 7

In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following would you expect of the genes of the bacteriophage?

Accepted Answer

A) regulation via acetylation of histones 
B) positive control mechanisms rather than negative 
C) control of more than one gene in an operon 
D) reliance on transcription activators 
E) utilization of eukaryotic polymerases 
A) regulation via acetylation of histones 
B) positive control mechanisms rather than negative 
C) control of more than one gene in an operon 
D) reliance on transcription activators 
E) utilization of eukaryotic polymerases

Question 8

Use the following information to answer the questions below.
Throughout history, human populations have been impacted by viral outbreaks. In the past 100 years we have seen several devastating epidemics and pandemics that have put people at risk. Worldwide, annual seasonal flu epidemics result in about three to five million cases of severe illness, and about 250 000 to 500 000 deaths annually. Most deaths associated with seasonal influenza in industrialized countries occur among people age 65 or older.
In 2009, a new strain of influenza, H1N1, entered the global scene. Within the year it had spread to 207 countries, infected 600 000 people, and killed 8000 worldwide. The pandemic alert was raised and a coordinated, concerted effort around the world was implemented to bring this flu under control. H1N1 is most likely a variation of the Spanish flu (also called H1N1); this flu was responsible for over 40 million deaths worldwide in the pandemic of 1918 (killing over 2.5% of the entire human population in one year).
-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 9

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.
-In a cell-free system, what other components would you have to provide for this virus to express its genes?

Accepted Answer

A) ribosomes, tRNAs and amino acids 
B) ribosomes, tRNAs, amino acids, and GTP 
C) RNA nucleotides and GTP 
D) RNA nucleotides, RNA polymerase, and GTP 
E) bean cell enzymes 
A) ribosomes, tRNAs and amino acids 
B) ribosomes, tRNAs, amino acids, and GTP 
C) RNA nucleotides and GTP 
D) RNA nucleotides, RNA polymerase, and GTP 
E) bean cell enzymes

Question 10

Use the following information to answer the next few questions.
Poliovirus is a positive-sense RNA virus of the picornavirus group. At its 5' end, the RNA genome has a viral protein (VPg) instead of a 5' cap. This is followed by a nontranslated leader sequence, and then a single long protein coding region (~7000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short-period use of the radioactive amino acids result in labelling of only very long proteins, while longer periods of labelling result in several different short polypeptides.
-What conclusion is most consistent with the results of the radioactive labelling experiment?

Accepted Answer

A) The host cell cannot translate viral protein with the amino acid analogues. 
B) Host cell ribosomes only translate the viral code into short polypeptides. 
C) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones. 
D) The RNA is translated into short polypeptides, which are subsequently assembled into large ones. 
E) The large radioactive polypeptides are coded by the host, whereas the short ones are coded for by the virus. 
A) The host cell cannot translate viral protein with the amino acid analogues. 
B) Host cell ribosomes only translate the viral code into short polypeptides. 
C) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones. 
D) The RNA is translated into short polypeptides, which are subsequently assembled into large ones. 
E) The large radioactive polypeptides are coded by the host, whereas the short ones are coded for by the virus.

Question 11

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 12

Viral genomes vary greatly in size and may include from four genes to several hundred genes. 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 13

The spread of viral disease in a human population occurs through which means?

Accepted Answer

A) mutation of existing viruses 
B) transmission through travel and movement 
C) handling animals that have viruses that jump the species barrier 
D) not getting vaccinated against the virus 
E) All of these examples can help spread a viral disease. 
A) mutation of existing viruses 
B) transmission through travel and movement 
C) handling animals that have viruses that jump the species barrier 
D) not getting vaccinated against the virus 
E) All of these examples can help spread a viral disease.

Question 14

Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life?

Accepted Answer

A) re-infection by a closely related herpesvirus of a different strain 
B) re-infection by the same herpesvirus strain 
C) co-infection with an unrelated virus that causes the same symptoms 
D) copies of the herpesvirus genome permanently maintained in host nuclei 
E) copies of the herpesvirus genome permanently maintained in host cell cytoplasm 
A) re-infection by a closely related herpesvirus of a different strain 
B) re-infection by the same herpesvirus strain 
C) co-infection with an unrelated virus that causes the same symptoms 
D) copies of the herpesvirus genome permanently maintained in host nuclei 
E) copies of the herpesvirus genome permanently maintained in host cell cytoplasm

Question 15

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.

Question 16

Antiviral drugs that have become useful are usually associated with which of the following properties?

Accepted Answer

A) ability to remove all viruses from the infected host 
B) interference with viral replication 
C) prevention of the host from becoming infected 
D) removal of viral proteins 
E) removal of viral mRNAs 
A) ability to remove all viruses from the infected host 
B) interference with viral replication 
C) prevention of the host from becoming infected 
D) removal of viral proteins 
E) removal of viral mRNAs

Question 17

The country or region hit hardest during the outbreak of SARS in 2002-2003 was

Accepted Answer

A) Asia. 
B) Canada. 
C) the United States. 
D) the UK. 
E) Australia. 
A) Asia. 
B) Canada. 
C) the United States. 
D) the UK. 
E) Australia.

Question 18

The SARS outbreak in 2003 resulted in ________ deaths in Canada.

Accepted Answer

A) 8000 
B) 1026 
C) 438 
D) 44 
E) none 
A) 8000 
B) 1026 
C) 438 
D) 44 
E) none

Question 19

Use the following information to answer the questions below.
Throughout history, human populations have been impacted by viral outbreaks. In the past 100 years we have seen several devastating epidemics and pandemics that have put people at risk. Worldwide, annual seasonal flu epidemics result in about three to five million cases of severe illness, and about 250 000 to 500 000 deaths annually. Most deaths associated with seasonal influenza in industrialized countries occur among people age 65 or older.
In 2009, a new strain of influenza, H1N1, entered the global scene. Within the year it had spread to 207 countries, infected 600 000 people, and killed 8000 worldwide. The pandemic alert was raised and a coordinated, concerted effort around the world was implemented to bring this flu under control. H1N1 is most likely a variation of the Spanish flu (also called H1N1); this flu was responsible for over 40 million deaths worldwide in the pandemic of 1918 (killing over 2.5% of the entire human population in one year).
-With H1N1, most deaths occurred under the age of 65. Why might this have been the case?

Accepted Answer

A) Seniors tend to stay at home so are not in contact with the disease. 
B) Seniors, in general, are more resistant to viral infection. 
C) Seniors may have had exposure to earlier H1N1 viruses and are thus more immune. 
D) This virus targeted the young and healthy. 
E) There is no possible explanation. 
A) Seniors tend to stay at home so are not in contact with the disease. 
B) Seniors, in general, are more resistant to viral infection. 
C) Seniors may have had exposure to earlier H1N1 viruses and are thus more immune. 
D) This virus targeted the young and healthy. 
E) There is no possible explanation.

Question 20

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.

Exam 19: Viruses

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

Which of the following is the best predictor of how much damage a virus causes?

H1N1 was declared ________ in June 2009.

A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have

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

In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following would you expect of the genes of the bacteriophage?

Viral genomes vary greatly in size and may include from four genes to several hundred genes. Which of the following viral features is most apt to correlate with the size of the genome?

The spread of viral disease in a human population occurs through which means?

Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life?

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

Antiviral drugs that have become useful are usually associated with which of the following properties?

The country or region hit hardest during the outbreak of SARS in 2002-2003 was

The SARS outbreak in 2003 resulted in ________ deaths in Canada.

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

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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