Mastering Biology Chapter 16 and 17 Reviews
Some viruses can be crystallized and their structures analyzed. One such virus is yellow mottle virus, which infects beans. This virus has a single-stranded RNA genome containing about 6,300 nucleotides. Its capsid is 25-30 nm in diameter and contains 180 identical capsomeres. If the yellow mottle virus capsid has 20 facets, how many proteins form each facet?
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Use the following information to answer the question below. Some viruses can be crystallized and their structures analyzed. One such virus is yellow mottle virus, which infects beans. This virus has a single-stranded RNA genome containing about 6,300 nucleotides. Its capsid is 25-30 nm in diameter and contains 180 identical capsomeres. If the yellow mottle virus capsid has 20 facets, how many proteins form each facet?
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Homeostasis is a living organism's
Ability to maintain constant internal conditions even when environmental conditions change
You are a doctor working at a clinic in Liberia. Which of the following patients are you most likely to diagnose with Ebola?
A man with a high fever, diarrhea, and vomiting
You are a doctor woking at a clinic in liberia. Which of the following patients are you most likely to diagnose with Ebola?
A man with a high fever, diarrhea, and vomiting.
You are a doctor in Egypt. Which of the following patients are you most likely to diagnose with schistosomiasis?
A patient with anemia and blood in the urine.
Which of the following series of events best reflects what we know about how the flu virus moves between species?
An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates and is passed to a new species such as a bird, and the virus mutates and can be transmitted to humans.
A human pandemic is
An epidemic that extends around the world
What is the function of reverse transcriptase in retoviruses?
It uses viral RNA as a template for DNA synthesis
What is the function of reverse transcriptase in retroviruses?
It uses viral RNA as a template for DNA synthesis.
Why have so many people with Lassa been turned away from hospitals in Sierra Leone?
It was unknown as to what the patients had
Why have so many people with Lassa been turned away from hospitals in Sierra Leone?
It was unknown as to what the patients had.
You are a doctor working in Sierra Leone. A patient presents with fever, vomiting, bleeding and a brain infection. Which would be best to diagnose?
Lassa
You work for the Centers for Disease Control and Prevention and have been sent to the country where this recent Ebola outbreak was first identified. Where do you go?
Guinea
Which of the following countries would be best to study to understand why polio has the ability to continue coming back?
Nigeria
Viruses are
Not alive because they are not made of cells and require a host cell for reproduction
Why is combination drug therapy for HIV/AIDS less likely to lead to resistance than single drug therapy?
The likelihood of one virus spontaneously mutating to be resistant to several different drugs at the same time is extremely small.
Why is combination drug therapy fro HIV/AIDS less likely to lead to resistance than single drug therapy?
The likelihood of one virus spontaneously mutating to be resistant to several different drugs t the same time is extremely small
Which of the following characteristics determine a virus's host range?
The proteins on its surface and that of the host
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?
The plants would develop the typical symptoms of TMV infection.
Most molecular biologists think that viruses originated from naked bits of cellular nucleic acid. Which of the following observations supports this theory?
Viral genomes are usually similar to the genome of the host cell.
Evidence suggests that factors which contribute towards the virulence of E. coli strain O157:H7, a bacterial strain reported to cause several food poisoning deaths, are caused by genes from a virus that infects bacteria. Considering this evidence, which statement most likely explains how the O157:H7 population acquired the genetic variation that distinguishes the strain from harmless E. coli strains, such as those that reside in our intestines?
The virus infected the bacterium, and allowed the bacterial population to replicate with a copy of the phage genome in each new bacterium
How does a virus differ from a bacterium?
Viruses, unlike bacteria, lack metabolic enzymes.
Evidence suggests that factors which contribute towards the virulence of E. coli strain O157:H7, a bacterial strain reported to cause several food poisoning deaths, are caused by genes from a virus that infects bacteria. Considering this evidence, which statement most likely explains how the O157:H7 population acquired the genetic variation that distinguishes the strain from harmless E. coli strains, such as those that reside in our intestines?
The virus infected the bacterium, and allowed the bacterial population to replicate with a copy of the phage genome in each new bacterium.
Which of the following is key to eradicating polio?
Vaccinations
Emerging viruses arise by
all of the above; mutation of existing viruses, the spread of existing viruses to new host species, the spread of existing viruses more widely within their host species
Viral envelopes can best be analyzed with which of the following techniques?
antibodies against specific proteins not found in the host membranes
Which of the following would currently be the most effective way to eliminate schistosomiasis in Africa?
deworming pill distribution
In the figure, at the arrow marked II, what enzyme(s) are being utilized?
host cell DNA polymerase
RNA viruses require their own supply of certain enzymes because
host cells lack enzymes that can replicate the viral genome
Viral DNA makes mRNA by the process of
transcription
Use the following information to answer the following question. In 1971, David Baltimore described a scheme for classifying viruses based on how the virus produces mRNA. the table shows the results of testing five viruses (AE) for nuclease specificity, the ability of the viral genome to act as an mRNA, and the presence (+) or absence () of each viruss own polymerase. Base on the table, which virus meets the requirements for a bacteriophage?
A
Use the following information to answer the following question. In 1971, David Baltimore described a scheme for classifying viruses based on how the virus produces mRNA. the table shows the results of testing five viruses (AE) for nuclease specificity, the ability of the viral genome to act as an mRNA, and the presence (+) or absence () of each viruss own polymerase. Based on the table, which virus meets the requirements for a bacteriophage?
A
Which of the following can be found in bacteria, but not viruses?
A cell membrane
Emerging viruses arise by
All of the listed responses are correct; mutation of existing viruses, the spread of existing viruses to new host species, the spread of existing viruses more widely within their host species
Please use the following information to answer the question(s) below. The herpesviruses 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 virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects 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 order to be able to remain latent in an infected live cell, HSV must be able to shut down what process?
Apoptosis of a virally infected cell
The herpesviruses 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 virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects 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 order to be able to remain latent in an infected live cell, HSV must be able to shut down what process?
Apoptosis of a virally infected cell
In areas where schistosomiasis is rampant, having people do which of the following would be most likely to decrease the frequency of this illness?
Avoid getting into lakes and ponds.
How is Ebola spread?
By person to person contact
You inhale the virus for the common cold. What sentinel cells does your immune system send out to determine the location of the infection?
CD4
Which of the following is why someone who has had a herpesvirus-mediated cold sore or genital sore may have flare-ups for the rest of his or her life?
Copies of the herpesvirues genome remaining as mini-chromosomes in some host cell nuclei
Which of the following is why someone who has had a herpesvirus-mediated cold sore or genital sore may have flare-ups for the rest of his or her life?
Copies of the herpesvirus genome remaining as mini-chromosomes in some host cell nuclei
Which of the following is NOT a characteristic of living things?
Creating energy
Which of the following is NOT characteristic of living things?
Creating energy
Which of the following is true?
Ebola and Lassa are both caused by viruses
Why aren't antibiotics typically given to Ebola patients?
Ebola is a virus, so antibiotics will be ineffective
You agree with the Centers for Disease Control and Prevention concerning the new plans to combat Ebola in Sierra Leone. What do you think?
Ebola patients should not be cared for at home
You are an epidemiologist for the CDC, specializing in schistosomiasis. Your goal is the reduce or eliminate this disease by focusing on the intermediate host. What are you researching?
Freshwater snail
You are an epidemiologist for the Centers for Disease Control, specializing in schistosomiasis. Your goal is to reduce or eliminate this disease by focusing on the intermediate host. What are you researching?
Freshwater snail
The pointer is indicating the virus's
Genome
Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations?
High mutation rate due to lack of proofreading of RNA genome replication errors.
In the figure, at the arrow marked II, what enzyme(s) are being utilized?
Host cell DNA polymerase
RNA viruses require their own supply of certain enzymes because
Host cells lack enzymes that can replicate the viral genome
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?
III
What happens first when a phage infects a bacterial cell and is going to enter a lysogenic cycle?
Linear DNA circularizes
What happens first when a phage infects a bacterial cell and is going to enter a lysogenic cycle?
Linear DNA circularizes.
Cycle A is the _______ cycle and cycle B is the ________ cycle.
Lytic... lysogenic
Cycle a is the _____ cycle and cycle B is the _____ cycle.
Lytic... lysogenic
Controlling populations of which of the following would likely cause a decline in cases of Lassa?
Mice
Based on what happened in Nigeria, what is most likely to occur in Sierra Leone?
Over time, the number of people with the LARGE mutation will increase
Based on what happened in Nigeria, what is most likely to occur in Sierra Leone?
Over time, the number of people with the LARGE mutation will increase.
Where are doctor most likely to find new polio patients to treat?
Pakistan
Where are doctors most likely to find new polio patients to treat?
Pakistan
Which of the following is polio best known for causing?
Paralysis
What is a virus that attacks a bacterium?
Phage
In 2009, a flu pandemic was believed to have originated when viral transmission occurred from pig to human, thereby earning the designation, "swine flu." Although pigs are thought to have been the breeding ground for the 2009 virus, sequences from bird, pig, and human viruses were all found within this newly identified virus. What is the most likely explanation of why this virus contained sequences from bird, pig, and human viruses?
Related viruses can undergo genetic recombination if the RNA genomes mix and match during viral assembly.
You work for the World Health Organization and are sent to the last known place where polio was found in Africa to help ensure it does not return. Where do you go?
Somalia
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
T4 protein and T4 DNA
Which of the following statements about viruses is FALSE?
The widespread use of antibiotics has led to resistant strains of viruses.
Most molecular biologists think that viruses originated from naked bits of cellular nucleic acid. Which of the following observations supports this theory?
Viral genomes are usually similar to the genome of the host cell
Suppose you were in charge of sending an unmanned space probe to a new planet in search of life. The probe would be able to collect and test samples and make observations, but the planet is too far away for the probe to be able to bring samples back to Earth. The probe is small and would only be able to run a few tests, so you want to pick a test for evidence of life that is broad enough to incorporate all forms of life as we know it. Which one of the following tests would be the best to use in this situation?
a test for the presence of cells that contain DNA
A human pandemic is
an epidemic that extends around the world
HIV uses which of the following processes to synthesize a DNA strand using its RNA genome as a template?
reverse transcription
Which of the following is key to eradicating polio?
vaccinations
In the lysogenic cycle
viral DNA is replicated along with host DNA