Microbiology Chapter 6

The protein shell that packages and protects the genome and also accounts for the bulk of a virion's mass is called a _________.
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The protein shell that packages and protects the genome and also accounts for the bulk of a virion's mass is called a _________.
Capsid
Which of the following would be the best general description of a "virus?"
Viruses are acellular infectious agents.
Which of the following is not a mechanism of an antiviral drug?
Blocking viral ribosomes
Bacteriophages use different mechanisms for host cell infection and viral replication. During the lytic replication pathway, bacteriophages infect the host bacterial cells and immediately build new virions. During which of the key steps is the genome packed into capsid and phage structures put together?
Assembly
Which of the following terms is used to describe the shape of a virus?
Icosahedral
In a(n) _________ infection, viral replication peaks, followed by immune clearance of the virus.
acute
Cells can only contain which of the following types of genomes?
A double-stranded DNA genome
Which of the following oncogenic viruses may integrate into the host genome?
Human papilloma viruses (HPVs)
You are comparing the size of different viruses. You are specifically interested in the size of the following viruses: Ebola virus, Poliovirus, Rhinivirus, and Pithovirus. Which of these viruses would be the smallest, and which the largest?
Poliovirus is the smallest; Pithovirus the largest.
Viruses do not infect which of the following organisms?
Viruses can infect all forms of life.
Which of the following viral genomes is immediately ready for translation after the virus gains entry into the cell?ssRNA+Why is there a need to be vaccinated with a new flu shot every year?The RNA genome of influenza mutates frequently, causing minor changes. This is referred to as antigenic drift.Which of the following statements incorrectly describes viral spikes?Lipid-based spikes make up the envelope that surrounds the capsid.Which of the following suffixes would be used to describe a viral family?viridaeWhich of the following acellular agents do not have any genetic material and therefore do not replicate?PrionsZika virus is best described as a(n) _________ virus with a ________ genome.enveloped, ssRNA+Which of the following is not a property used to group viruses?Unicellularity versus multicellularityNucleic acid detection techniques:can detect new viruses and early-stage infections that antibody-antigen tests are likely to miss.Which of the following steps is found in the lysogenic replication pathway but not in the lytic replication pathway?IntegrationThe most common drugs that block replication are ________.nuceloside analogsWhich of the following methods is used to cultivate bacteriophages in the laboratory setting?Bacteriophages are cultivated in bacteria in liquid broth or on solid medium.Which of the following is a major difference between bacteriophages and animal viruses?Animal viruses enter the host cell; bacteriophages inject their genome into the host without entering.Which type of method is used to determine if a prior exposure to a virus occurred?Latex agglutination testThe rabies virus primarily affects the nervous system. The specificity that the rabies virus has for neuronal host cells is primarily dictated by __________________________.the spikes that protrude from its viral envelopeChoose the correct statement about viral evolution.RNA viruses mutate faster than DNA viruses due to a lack of proofreading replicative enzymes.In the Spring of 2009, a novel H1N1 virus emerged that had a new combination of genes from pigs, humans, and birds. As a result, the virus spread quickly, resulting in a swine flu pandemic. Which of the following concepts explains why the outbreak occurred?Antigenic shiftViruses are considered to be non-living pathogens for which reason?their lack of metabolic processesA previously undescribed infection has been detected among inhabitants in an isolated village in a remote tropical rainforest. When serum from an infected individual is passed through a filter, the infection can be transmitted to laboratory animals. Nothing is observed when the serum is examined with a light microscope at the highest magnification. Biochemical tests show the presence of RNA and protein but no carbohydrates or lipids. This data is consistent with what type of infectious agent?VirusWhich statement is not true about the virus capsid?Because the capsid is not essential to the virus, it is not a useful target for antiviral drugs.When a virus has an envelope,it likely escapes its host cell by budding.Viral spikesallow the virus to attach and enter host cells, may be a target for the host immune system, and show specificity in binding to particular structures on the host cell.Which of the following are contributors to viral genome evolution?quick replication time and the large number of virions released within a hostWhich description of antigenic drift and antigenic shift in the influenza virus is incorrectly matched?Antigenic drift: Often involves reassortment of viral strains in an animal host followed by a "species jump" to humans.Which property is not used to classify viruses?tissue types infectedViruses which infect many different tissues types are said to have a(n)broad tropism.Which of the following is a key difference between lytic and lysogenic bacteriophage replication cycles?The lytic replication cycle ends with host cell lysis and release of newly formed bacteriophage particles, whereas lysogenic replication leads to prophage formation.Which of the following is an example of phage conversion?Infection of Streptococcus pyogenes with T12 phage enables the bacteria to produce erythrogenic toxins, allowing it to cause scarlet fever.You observe that a novel virus penetrates the host cell through membrane fusion. Which of the following statements must also be true regarding this virus and its replicative cycle?The virus releases from host cells by budding.An elderly patient who contracted chickenpox as a child now has shingles as an adult. You explain to your patient that both diseases are caused by the same virus, which lays dormant in the body prior to reactivation. Based on this information, choose the true statement.During dormant periods, the virus exists episomally inside of infected host cells.During lytic replication of bacteriophage, which process uses factors from the host cell, rather than coded by the viral genome?enzymes which transcribe and translate viral genesWhich stage of animal virus replication may be blocked by a drug that binds with the viral spike?attachmentHIV, the virus which causes AIDS, interacts with two receptors on the host cell membrane: CD4 and CCR5. A small percentage of individuals have a genetic mutation which causes their cells to lack CCR5. These individuals will never develop AIDS nor are they able to pass HIV on to others. Which part of viral replication is being blocked by the lack of a receptor?HIV cannot attach to the host cell without the proper membrane receptor.Oncogenic virusesstimulate uncontrolled host cell division.Which is not a cancer linked to a specific virus?Skin cancerWhich of the following is an unsuitable culture method for an animal virus?Direct inoculation of virus onto blood agarA nurse experienced an accidental needle stick while treating a patient who has hepatitis C. The seroconversion window for hepatitis C is approximately 6-8 weeks. Given this information, which of the following viral detection methods would be most appropriate for detecting a hepatitis C infection in the nurse one week following the needle stick?PCR-based detection of hepatitis C RNA SubmitA young patient who underwent surgical placement of depth electrodes for epilepsy treatment contracted a prion disease. Cortical electrode probes are known to be reused in patients. Based on this information, which of the following prion diseases did the young patient most likely contract?Iatrogenic Creutzfeldt-Jakob DiseaseOne ml of a liquid suspension of bacteriophage is mixed with its host bacteria and plated. After incubation, the plate is completely clear. What is the probable explanation?The phage concentration was so high that all the host bacterial cells were killed.What does the plaque assay determine?number of bacteriophage in a sampleAn individual uses an in-home test kit one week after engaging in high-risk behavior for HIV infection. The test kit uses a saliva sample that is mailed to a lab where an agglutination test to detected HIV antibodies is run. The results come back negative for HIV. What should the patient consider regarding these test results?One week may not be enough time for HIV antibodies to be detected.Challenges in developing effective antiviral drugs with minimal side effects to the patient includeviruses use the cell's own machinery and metabolism for replication.Prions aremisfolded proteins which can cause normal versions to also misfold.Which of the following prion diseases may be acquired by eating beef contaminated with a cattle prion?variant CJD