Question 1

Which of the following is NOT a method employed to control the spread of viruses?

Accepted Answer

A)  Antibiotics 
B)  Destruction of infected hosts 
C)  Washing hands 
D)  Use of condoms during intercourse 
E)  Mosquito net 
A)  Antibiotics 
B)  Destruction of infected hosts 
C)  Washing hands 
D)  Use of condoms during intercourse 
E)  Mosquito net A

Question 2

You are studying an unknown virus and note that upon contact with a specific host, the virus's terminal tail fibres attach and the outer layer twists and contracts. This forces the core of the virus's tail through the host's cell membrane such that the viral genome enters the host. Based on this information, the host for this virus must be a

Accepted Answer

A)  plant. 
B)  animal. 
C)  bacteria. 
D)  fungi. 
E)  the virus could infect any host. 
A)  plant. 
B)  animal. 
C)  bacteria. 
D)  fungi. 
E)  the virus could infect any host. C

Question 3

The best definition of a virus species is a

Accepted Answer

A)  self-perpetuating nucleotide fragment. 
B)  obligate host-dependant parasitic entity. 
C)  viral lineage that occupies a particular ecological niche. 
D)  virion or virions requiring a suitable replicating environment. 
E)  conserved nucleotide sequences, sharing commonality in hosts, symptoms and reproductive processes. 
A)  self-perpetuating nucleotide fragment. 
B)  obligate host-dependant parasitic entity. 
C)  viral lineage that occupies a particular ecological niche. 
D)  virion or virions requiring a suitable replicating environment. 
E)  conserved nucleotide sequences, sharing commonality in hosts, symptoms and reproductive processes. C

Question 4

When a virion comes into contact with a suitable host cell, the virus switches to its reproductive phase which consists of

Accepted Answer

A)  enzyme denaturation. 
B)  coat protein degradation. 
C)  lipoprotein envelope hydrolysis. 
D)  metabolic inertia. 
E)  metabolically active genes. 
A)  enzyme denaturation. 
B)  coat protein degradation. 
C)  lipoprotein envelope hydrolysis. 
D)  metabolic inertia. 
E)  metabolically active genes.

Question 5

Which of the following statements in relation to the genome of a virus is CORRECT?

Accepted Answer

A)  Some viruses have divided genomes in separate packages. 
B)  Viruses do not have circular genomes. 
C)  A viral genome is always packaged within a single, infectious virion. 
D)  Like all living organisms, viral genomes are composed of DNA. 
E)  Viruses copy their own genomes before using their hosts cellular machinery to produce proteins and assemble new viral particles. 
A)  Some viruses have divided genomes in separate packages. 
B)  Viruses do not have circular genomes. 
C)  A viral genome is always packaged within a single, infectious virion. 
D)  Like all living organisms, viral genomes are composed of DNA. 
E)  Viruses copy their own genomes before using their hosts cellular machinery to produce proteins and assemble new viral particles.

Question 6

A virus is isolated independently from two infected individuals. Each individual shows similar symptoms. Under an electron microscope, both viruses share common morphological features. Based on this information, what would you predict in relation to their respective nucleotide sequences?

Accepted Answer

A)  The two viruses are clearly of the same species, therefore they would have identical genomes. 
B)  They may be the same, slightly different or substantially different. The high rate of mutation in viruses makes large genome differences common. 
C)  Quite different, as shared symptoms and morphology do not necessarily correlate to nucleotide conservation. 
D)  As many viruses do not have DNA, nucleotide differences or similarities are irrelevant. 
E)  They would be the same, or may differ slightly. 
A)  The two viruses are clearly of the same species, therefore they would have identical genomes. 
B)  They may be the same, slightly different or substantially different. The high rate of mutation in viruses makes large genome differences common. 
C)  Quite different, as shared symptoms and morphology do not necessarily correlate to nucleotide conservation. 
D)  As many viruses do not have DNA, nucleotide differences or similarities are irrelevant. 
E)  They would be the same, or may differ slightly.

Question 7

A retrovirus is defined as

Accepted Answer

A)  a virus with an RNA genome that replicates by inserting DNA into a host's genome. 
B)  a virus with a DNA genome that replicates by inserting DNA into a host's genome. 
C)  a virus with a DNA genome that replicates by inserting RNA into a host's genome. 
D)  a virus with a RNA genome that replicates by inserting RNA into a host's genome. 
E)  any of a group of viruses that can cause cancer. 
A)  a virus with an RNA genome that replicates by inserting DNA into a host's genome. 
B)  a virus with a DNA genome that replicates by inserting DNA into a host's genome. 
C)  a virus with a DNA genome that replicates by inserting RNA into a host's genome. 
D)  a virus with a RNA genome that replicates by inserting RNA into a host's genome. 
E)  any of a group of viruses that can cause cancer.

Question 8

All viruses consist of

Accepted Answer

A)  genome. 
B)  lipoprotein envelope. 
C)  DNA or RNA. 
D)  protective coat. 
E)  protein. 
A)  genome. 
B)  lipoprotein envelope. 
C)  DNA or RNA. 
D)  protective coat. 
E)  protein.

Question 9

Viral genomes can take several forms. Which of the following is NOT a type of genome that can be found in a viral cell?

Accepted Answer

A)  dsDNA 
B)  combination of both DNA and RNA 
C)  dsRNA 
D)  ssDNA 
E)  ssRNA 
A)  dsDNA 
B)  combination of both DNA and RNA 
C)  dsRNA 
D)  ssDNA 
E)  ssRNA

Question 10

Most viruses are transmitted by

Accepted Answer

A)  faecal contamination. 
B)  pollen or seed. 
C)  vectors. 
D)  milk. 
E)  water. 
A)  faecal contamination. 
B)  pollen or seed. 
C)  vectors. 
D)  milk. 
E)  water.

Question 11

After the genes of a virus use a host's metabolic systems to produce proteins and DNA, what is formed once the replicated viral genomes and viral proteins finish assembling?

Accepted Answer

A)  Virions 
B)  Lipoprotein envelopes 
C)  Virus coats 
D)  Cell lysis proteins to facilitate the release of newly created viral particles 
E)  Viral genomes 
A)  Virions 
B)  Lipoprotein envelopes 
C)  Virus coats 
D)  Cell lysis proteins to facilitate the release of newly created viral particles 
E)  Viral genomes

Question 12

A scientist has identified a repetitive sequence of DNA from a mammalian species that appears to move around its genome. If this sequence were found to have nucleotide similarities to viruses, it is likely to be a

Accepted Answer

A)  transposon. 
B)  retrovirus. 
C)  retrotransposon. 
D)  satellite virus. 
E)  replicon. 
A)  transposon. 
B)  retrovirus. 
C)  retrotransposon. 
D)  satellite virus. 
E)  replicon.

Question 13

A virus with a negatively stranded genome has its genome chemically extracted from a virion. Why is this genome NOT contagious?

Accepted Answer

A)  Because it is no longer associated with viral proteins 
B)  Because the genome must first be transcribed into a plus strand 
C)  Because chemical extraction shears nucleic acids 
D)  Because it is not incorporated into a suitable host genome 
E)  Because negative strands are non-transmissible 
A)  Because it is no longer associated with viral proteins 
B)  Because the genome must first be transcribed into a plus strand 
C)  Because chemical extraction shears nucleic acids 
D)  Because it is not incorporated into a suitable host genome 
E)  Because negative strands are non-transmissible

Question 14

A virus with a plus-stranded genome can be

Accepted Answer

A)  translated directly from subgenomic mRNAs. 
B)  attenuated after being chemically deproteinised. 
C)  translated only after a complimentary reading strand is synthesised. 
D)  identified via light microscopy. 
E)  transcribed from genomic ssDNA. 
A)  translated directly from subgenomic mRNAs. 
B)  attenuated after being chemically deproteinised. 
C)  translated only after a complimentary reading strand is synthesised. 
D)  identified via light microscopy. 
E)  transcribed from genomic ssDNA.

Question 15

Why is a viral infection difficult to control via biochemical means without harming the host?

Accepted Answer

A)  Because they are very small. 
B)  Because their genomes can be so variable. 
C)  Because they recombine so readily, they often contain sequences homologous with their hosts. Therefore if these sequences are targeted, the host is also damaged. 
D)  Because viruses employ their hosts biochemical systems to reproduce. 
E)  Because they do not respond to antibiotics. 
A)  Because they are very small. 
B)  Because their genomes can be so variable. 
C)  Because they recombine so readily, they often contain sequences homologous with their hosts. Therefore if these sequences are targeted, the host is also damaged. 
D)  Because viruses employ their hosts biochemical systems to reproduce. 
E)  Because they do not respond to antibiotics.

Question 16

Which of the following is an example of a virus with one of the smallest known genomes, and what is the genome's approximate size?

Accepted Answer

A)  Tobacco mosaic virus, genome of approximately 6000 nucleotides 
B)  Poxvirus, genome of approximately 20,000 nucleotides 
C)  Lambda phage, genome of approximately 4000 nucleotides 
D)  AIDS, genome of approximately 10,000 nucleotides 
E)  Potato Y potyvirus, genome of approximately 8000 nucleotides 
A)  Tobacco mosaic virus, genome of approximately 6000 nucleotides 
B)  Poxvirus, genome of approximately 20,000 nucleotides 
C)  Lambda phage, genome of approximately 4000 nucleotides 
D)  AIDS, genome of approximately 10,000 nucleotides 
E)  Potato Y potyvirus, genome of approximately 8000 nucleotides

Question 17

Viruses are polyphyletic. From this term, you can accurately conclude that viruses have independently evolved how many times?

Accepted Answer

A)  More than once 
B)  Once 
C)  Twice 
D)  More than twice 
E)  Unknown 
A)  More than once 
B)  Once 
C)  Twice 
D)  More than twice 
E)  Unknown

Question 18

Which of the following is NOT an example of how a virus can aid its own dispersal?

Accepted Answer

A)  Nutrient diversion from ovaries instead used to greatly increase pollen production, to faciliate the dispersal of a pollen borne plant virus. 
B)  Increased CO2 output of infected hosts to attract additional viral vectors. 
C)  Fever in hosts infected with viruses that are mosquito borne. 
D)  Coughing and sneezing of mammalian hosts to produce airborne, contaminated droplets. 
E)  Plant virus causing discolouration to attracts more viral vectors. 
A)  Nutrient diversion from ovaries instead used to greatly increase pollen production, to faciliate the dispersal of a pollen borne plant virus. 
B)  Increased CO2 output of infected hosts to attract additional viral vectors. 
C)  Fever in hosts infected with viruses that are mosquito borne. 
D)  Coughing and sneezing of mammalian hosts to produce airborne, contaminated droplets. 
E)  Plant virus causing discolouration to attracts more viral vectors.

Question 19

A virion is defined as

Accepted Answer

A)  another common term for a virus. 
B)  Latin for 'contagious fluid'. 
C)  a very small virus. 
D)  the inert, transmission stage of a virus. 
E)  the reproductive, metabolically active stage of a virus. 
A)  another common term for a virus. 
B)  Latin for 'contagious fluid'. 
C)  a very small virus. 
D)  the inert, transmission stage of a virus. 
E)  the reproductive, metabolically active stage of a virus.

Question 20

A number of seminal experiments by plant pathologists on tobacco infected with tobacco mosaic virus (TMV) established the principle of the existence of viruses. Which of the following were NOT techniques used to help establish the existence of viruses?

Accepted Answer

A)  Precipitation of infective agents with ethanol that retained infectivity 
B)  Culturing of small particles 
C)  The ability of infective agents to be passed through a porcelain filter with pores too small to permit bacteria to pass through them 
D)  Sap from diseased plants could infect non-diseased plants 
E)  Diffusion of infective agents from sap into a block of gelatin 
A)  Precipitation of infective agents with ethanol that retained infectivity 
B)  Culturing of small particles 
C)  The ability of infective agents to be passed through a porcelain filter with pores too small to permit bacteria to pass through them 
D)  Sap from diseased plants could infect non-diseased plants 
E)  Diffusion of infective agents from sap into a block of gelatin

Exam 14: Viruses

Which of the following is NOT a method employed to control the spread of viruses?

The best definition of a virus species is a

When a virion comes into contact with a suitable host cell, the virus switches to its reproductive phase which consists of

Which of the following statements in relation to the genome of a virus is CORRECT?

A virus is isolated independently from two infected individuals. Each individual shows similar symptoms. Under an electron microscope, both viruses share common morphological features. Based on this information, what would you predict in relation to their respective nucleotide sequences?

A retrovirus is defined as

All viruses consist of

Viral genomes can take several forms. Which of the following is NOT a type of genome that can be found in a viral cell?

Most viruses are transmitted by

After the genes of a virus use a host's metabolic systems to produce proteins and DNA, what is formed once the replicated viral genomes and viral proteins finish assembling?

A scientist has identified a repetitive sequence of DNA from a mammalian species that appears to move around its genome. If this sequence were found to have nucleotide similarities to viruses, it is likely to be a

A virus with a negatively stranded genome has its genome chemically extracted from a virion. Why is this genome NOT contagious?

A virus with a plus-stranded genome can be

Why is a viral infection difficult to control via biochemical means without harming the host?

Which of the following is an example of a virus with one of the smallest known genomes, and what is the genome's approximate size?

Viruses are polyphyletic. From this term, you can accurately conclude that viruses have independently evolved how many times?

Which of the following is NOT an example of how a virus can aid its own dispersal?

A virion is defined as

A number of seminal experiments by plant pathologists on tobacco infected with tobacco mosaic virus (TMV) established the principle of the existence of viruses. Which of the following were NOT techniques used to help establish the existence of viruses?

Nature of Molecules

Biomolecules

The Chemistry of Life

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Movement Across Membranes

Harvesting Energy

Cells, Tissues and Signals

Cell Division

Inheritance

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Gene Expression

Genomes, Mutation and Cancer

Genetic Engineering and Biotechnology

Reproduction, Growth and Development of Flowering Plants

Structure of Plants

Plant Nutrition, Transport and Adaptation to Stress

Plant Hormones and Growth Responses

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Homeostasis: Water, Solutes and Excretion

Gas Exchange in Animals

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Hormonal Control in Animals

Nervous Systems

Animal Movement

Animal Behaviour

Evolving Life

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Mechanisms of Evolution

Bacteria

The Protists

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