Microbiology final.docx

Microbiology final Sporulating bacteria are able torrect!    survive harsh conditions like high heat, dehydration and low nutrient levels.    chemotax to an area of infection by following a chemical signal.    share genes on a plasmid by horizontal gene transfer.    form biolfilms.    prevent phag...

Microbiology final Sporulating bacteria are able torrect!    survive harsh conditions like high heat, dehydration and low nutrient levels.    chemotax to an area of infection by following a chemical signal.    share genes on a plasmid by horizontal gene transfer.    form biolfilms.    prevent phagocytosis by inhibiting adherence.     Which tool from the microbiologist's toolbox is used to prevent growth of microbes in the air and on tools?    Stains/dyes    Loop    Petri dishes    Bunsen burner/microincinerator Growth media     Which statement correctly describes the eukaryotic and prokaryotic ribosome?    The eukaryotic ribosome reads A,C,G, and T base pairs while the prokaryotic ribosome reads A,C,G, and U.   Correct!    The ribosome in the eukaryotic cell cytoplasm is larger than the prokaryotic ribosome.      The eukaryotic ribosome makes mRNA and the prokaryotic ribosome makes DNA.      The eukaryotic ribosome is located only in the cytoplasm while the prokaryotic ribosome is located in the cytoplasm and in some of the cell’s organelles.     Burt is attempting to recreate Pasteur’s famous experiment disproving Spontaneous Generation. He adds broth to a flask, heats the neck to bend it into an S-shape, and then heats the broth. After several days, Burt observes that the broth is cloudy and there is microbe growth. Which of the following could have led to this result?    A laboratory down the hall studies a motile bacteria that possess several flagella that propel the cells.      Burt used chicken broth in the flask instead of beef broth used by Pasteur.      When heating the flask, the steam was allowed to escape through the open end of the S-shaped neck.      After the flask had cooled, Burt handled it with his bare hands and set it on a countertop that was not sterilized.   Correct!    Burt did not bring the broth to a full boil but left it at low heat for a long period of time.     The lysogenic cycle and the lytic cycle of bacteriophage are depicted in Figures 6.7 and 6.8 in your book (https://openstax.org/details/books/microbiologyLinks to an external site.) and in our lecture slides for Chapter 6. Which of the following ONLY happens during the lysogenic cycle (NOT during the lytic cycle)?      The bacteriophage directs the host cell to make molecules for building new bacteriophage.   Correct!    The viral DNA is integrated into the host cell genome.      The host cell dies.      The bacteriophage injects its genome into the host cell.     Escherichia coli is a usually harmless bacteria but can sometimes cause food poisoning when ingested. Which statement about the binomial nomenclature system used to name Escherichia coli is FALSE?    You can abbreviate the name by writing the full genus name and the first letter of the species name.    The name should be written in italics, not in normal font.    coli is the species name.   There is only one type of organism of each species.     Which of the following statements describes the process of horizontal gene transfer?    DNA transferred to the next generation of bacteria from a related cell.   Correct!    Gaining a single new gene sequence from outside of the cell.      Replication of genomic DNA to be passed on the daughter cells.      A DNA mutation that is passed on to offspring by the process of DNA replication and cell division.     After penetration, animal viruses need to be uncoated but bacteriophage need not be. Why?    The spikes of animal viruses are added to the capsid in the uncoating step. Phage don’t have spikes.      Animal viruses insert their DNA into the host cell genome in the uncoating step and phage are not able to insert DNA into the host.      The uncoating step converts the RNA genome of animal viruses to DNA, which is not required for phage with a DNA genome.      The enveloped animal viruses exit the host cell in the uncoating step, bacteriophage lyse the host cell.   Correct!    Bacteriophage inject their DNA into the host during penetration so the capsid doesn’t enter the host cell.     How do the cell walls of fungi and bacteria differ? Correct!    Only bacteria cell walls contain peptidoglycan.      Only fungi cell walls contain phospholipids.      Only bacteria cell walls contain cellulose.      Fungi don’t have cell walls because they are not cellular.     All viruses destroy their host cell during release.  True   False     In comparing the bacteria shown in the figure below the genotypes of B. cereus and B. anthracis are _____, which would lead to their phenotypes being ____ if these genes are expressed into proteins in B. anthracis.    the same, different      different, the same      the same, the same  rect!    different, different     How many of the following statements are reasons why microbes are important to human life on Earth? Microorganisms provide models that give us fundamental knowledge about life processes. Humans use microbes for bioremediation. Microbe fermentation products are used in food and beverage production. Microbes are essential for life as we know it and for the processes that support life. Human and microbe reproduction are similar. You Answered    1 none of the statements are reasonsou Answered    3ou Answered    5 Answered    2Correct!    4   In the figure, which cell envelope includes lipopolysaccharide (LPS) molecules?    The answer cannot be determined from the information provided.   Correct!    b      both a and b      neither a or b      a     What is unique about the helminths compared to other categories of microorganisms?    Helminths are motile.      Helminths are comprised of cells that contain a nucleus.      Helminths are pathogens.      Helminths contain peptidoglycan in the cell walls.   Correct!    Helminths can be viewed without a microscope during part of their life cycle.     Viruses are unable to reproduce outside of a host cell. Correct!    True      False     For a bacteriophage, which of the following is a disadvantage of the lytic cycle? Question authored by: Layne    The virus is inactive.   Correct!    The host cell lyses.      The viral genome is integrated into the host cell DNA.      The virus replicates indefinitely, leading to many new virions.     To reduce the risk of open flame from Bunsen burners, microbiologists are increasingly using which of the following devices for easy, rapid benchtop sterilization of small pieces of equipment?    growth media   Correct!    microincinerator      inoculation loop      incubators     Keeping in mind how Griffith did his transformation experiments, which of the following types of Strepococcus pneumoniae, when combined into the same syringe, will NOT kill mice? (R refers to rough strain, and S refers to smooth strain)    None of these mixtures will kill mice      Live R mixed with heat-killed S      Heat-killed R mixed with live S   Correct!    All of these mixtures will kill mice      Live R mixed with live S     Transduction is the transfer of DNA from a donor to a recipient cell    by crossing over   as naked DNA in solution.   by a bacteriophage. by cell-to-cell contact.     If Pasteur had not boiled the broth at the start of the experiment, what would happen after several days?    The broth would eventually evaporate through the neck of the flask.   Correct! Microbes would grow in the broth and it would become contaminated.      Microbes from the air would be able to move past the S neck and grow in the broth.      The broth would remain sterile and no microbe growth would be observed.      The broth would solidify in the flask.     Transformation is the transfer of DNA from a donor to a recipient cell    by sexual reproduction.   by crossing over.   as naked DNA in solution.   by cell-to-cell contact.   by a bacteriophage.     An antibiotic that specifically targets the 70S ribosome will have NO effect on which of the following?    Human ribosomes attached to the endoplasmic reticulum Correct!    Human ribosomes in the cytoplasm AND Human ribosomes attached to the endoplasmic reticulum   Human ribosomes in the cytoplasm Mitochondria   Bacterial ribosomes Which of the following is a cell undergoing transformation?    S. aureus that is not able to donate DNA to other bacteria during conjugation because it doens't have the F factor gene.    Salmonella that is unable to ferment lactose.t!    A cell that takes up foreign DNA by transformation and incorporates the DNA into its genome.   A bacteria cell that has DNA mutations after having been exposed to a mutagen.    E. coli that has infected a human host by adhering to mucous membranes.   The core of every virus particle always contains ______.    enzymes   capsomeres    DNA    DNA and RNA    either DNA or RNA     Conjugation differs from other means of horizontal gene transfer between bacteria cells because conjugation requires    heat-killed cells to release their DNA.   physical contact between the bacteria cells by a pili.   cell division.    a bacteriophage virus.    DNA replication.     Fimbriae help bacteria    synthesize proteins,    attach and form biofilms. move by twitching and gliding motility.    replicate DNA.   transfer DNA to neighboring bacteria.     Bacteria with plasmids are more likely to be ___ compared to bacteria without plasmids.    vibrio Gram positive   resistant to antibiotics     Viruses are unable to reproduce outside of a host cell. Correct!    True False   JayVaugh has a very sore throat. Analysis of a swab from his nose confirmed that the causative organism is Bacillus anthracis, a gram-positive bacteria. Imagine that you are the technician looking at the Gram stain from JayVaugh’s culture. What would you expect to see as you look through the microscope? Correct!    purple, rod-shaped organisms      pink, spherical-shaped organisms arranged in chainlike formations      pink, rod-shaped organisms arranged in pairs      purple, spherical-shaped organisms arranged in chainlike formations     In 1994 a civil war in Rwanda displaced 3.9 million people, many of whom fled to refugee camps in Goma, Zaire. Conditions in refugee camps led to rapid spread of infectious diseases including a disease causing severe, watery diarrhea. Microbes isolated from the stool samples of these patients  with Gram stained showed a curved, Gram negative microorganism to be present. This microbe was identified as Vibrio cholerae. Based on this information and what you know from chapter 3, what can you conclude?orrect!    V. cholerae has a two plasma membranes that surround a peirplasmic space and a peptidoglycan cell wall. The V. cholerae have a single plasma membrane and a thick peptidoglycan cell wall. V. cholerae does not have a capsule since it is a Gram-negative microbe. The V. cholerae will be present in grape-like clusters of arrangement.  Clostridium difficile is a bacteria that causes the gastrointestinal disease C. diff. From this statement, select all that you can conclude about C. difficile? You Answered    Clostridium is the species of this bacteria.   C. difficile is a pathogen.   C. difficile is prokaryotic.   C. difficile has a cell wall made of peptidoglycan. C. difficile is a coccus.     You have isolated a mutant strain of Serratia marscesens that has an abnormal ribosome that is not functioning well. Which of the following might be affected by this change? ability to survive harsh environmental conditions biofilm formation motility production of proteins three dimensional shape of the cell     You are working with two microbe cultures in the lab; one is a bacteria and one is a fungus. The labels have fallen off and you need to determine their identity. What information about the cultures could help you distinguish the two tubes? Knowing that the cells are eukaryotic/prokaryotic. Knowing if the cells have a cell membrane. Knowing if the cells have a cell wall. Knowing that the cells have a DNA genome.     Although lytic phage are not able to insert DNA into the host cell’s genome, they are able to carry out transduction that leads to increased diversity within a bacterial population. Which of the following is the most likely explanation of how a lytic phage carries out transduction?    When the new phage particles are assembled, a bacterial plasmid is inserted into the phage head. When the phage DNA is excised, part of the bacterial DNA is also cut. When the phage exit the host cell by lysis, fragments of host cell DNA are released and taken up by bacteria cells in the environment. During conjugation, the phage carries a part of the bacterial chromosome through the pilus.  When the phage DNA is transcribed, an error is made in the newly made RNA molecule. Which of the following could alert a human's immune system to a bacterial infection?    flagella ribosomes DNA   peptidoglycan cell membrane   Herpes simplex virus type 2 (HSV-2) uses epithelial cells in the cervix (part of the female sex organs) as a host cell. HSV-2 does not normally infect epithelial cells in other areas of the body. Which characteristics of HSV-2 explains this tissue tropism?    HSV-2 is small in size. HSV-2 has spikes that specifically connect to the surface of cervical epithelial cells. HSV-2 is inactive outside of its host cell HSV-2 has a DNA genome. HSV-2 is an enveloped virus.     Your patient has a constant sensation of needing to urinate, feels burning when urinating, and has cloudy urine. You take a urine sample and culture it (allow microbes present in the sample to grow) in the lab. After performing a Gram stain, you conclude that the patient has a urinary tract infection and the causative microbe is the Gram positive bacteria, Staphylococcus saprophyticus. Which of the following statements are TRUE?    The causative bacteria is rod-shaped and arranged in long chains The bacteria causing the infection is of the genus saprophyticus. S. saprophyticus has a double plasma membrane. S. saprophyticus has a periplasmic space in between the cell membrane and cell wall. S. saprophyticus contains teichoic acid in the cell wall.     Tamiflu is a common medication given for influenza treatment. It works by blocking sialic acid molecules on the surface of host cells to prevent influenza virus from leaving the host cell. Which statement reflects the mechanism of Tamiflu's action? Tamiflu interferes with the release of the budding viruses from the infected host cells. Tamiflu interferes with the replication of the RNA genome of the flu virus Tamiflu blocks protein synthesis of the viral genome Tamiflu interferes with the metabolic properties of the virus. Question 1  1 / 1 pts An organism that can use only oxygen as the final electron acceptor in it electron transport chain may also have the ability to perform fermentation. Correct!    True      False     Question 2  1 / 1 pts A bacteria culture was grown in a glucose medium without O2. O2 was added to the medium at the time marked X. The rates of glucose and oxygen (O2) consumption and number of cells are shown in the Figure. Addition of O2 to the medium at time X resulted in    a slower growth rate of the bacteria.   Correct!    the bacteria switching to aerobic metabolism.      less efficient metabolism.      the bacteria performing fermentation.      less production of ATP.     Question 3  1 / 1 pts The space between the cell membrane and the cell wall is important during aerobic respiration. Why? Correct!    Hydrogen ions are transported into the space to set up a hydrogen gradient.      Electron carriers are located in this space.      Oxygen combines with electrons in that space to form water.      Pyruvate is transported into the space to be converted into acetyl coenzyme A to enter the Krebs cycle.     Question 4  1 / 1 pts A major difference between anaerobic respiration and aerobic respiration is that Correct!    anaerobic respiration uses an inorganic molecule as a final electron acceptor while aerobic respiration uses oxygen.      anaerobic respiration requires breathing while aerobic respiration does not. only human cells are capable or aerobic respiration.      aerobic respiration uses an electron transport chain while anaerobic respiration does not.      anaerobic respiration produces more ATP molecules than aerobic respiration.     Question 5  1 / 1 pts Inhibitors that bind away from the enzyme's active site to prevent substrate binding to the enzyme are Correct!    noncompetitive.      ions.      competitive.      coenzymes.      denatured.     Question 6  1 / 1 pts The figure below shows the Electron Transport System (ETS) embedded in the plasma membrane of a bacteria cell. Use what you know about ETS structure and function to identify "2".    production of ATP      formation of water   Correct!    the path of H+      production of ADP      FADH2 reduction     Question 7  1 / 1 pts To access energy required to do cellular work like copying DNA or building proteins, cells need to Correct!    breakdown ATP into ADP and Pi.      build ATP from ADP and Pi.      build sugars from ATP.      breakdown enzymes to build ATP.     Question 8  0 / 2 pts Select the statement that is TRUE for all three types of metabolism; aerobic respiration, anaerobic respiration, and fermentation.    Between 5-36 ATP are produced.   You Answered    Much or most of the ATP produced is produced by an electron transport system.      End products are CO2 and H2O.      Process includes glycolysis.      End products are useful for identification and may include lactic acid, ispropanol, and ethanol.     Question 9  1 / 2 pts Which of the following molecules are produced in the Electron Transport System during aerobic respiration? Select all that are produced.    glucose   Correct!    ATP   Correct!    water   You Answered    oxygen     Question 10  2 / 2 pts Escherichia coli needs to obtain only a few compounds from the environment to synthesize more than 5,000 compounds, thus E. coli produces   Correct!    a large variety of enzymes in order to synthesize almost every compound it needs to survive.      large numbers of a few important enzymes to synthesize almost every compound it needs to survive.      enzymes with low specificity active sites in order to bind to a number of different substrates.      enzymes with a high turnover number of substrate molecules in order to maintain the cell.     Question 11  1 / 1 pts During which phase of the growth curve are bacterial species decreasing or experiencing no increase in the number of living cells? Select all that apply. Question authored by: Trevor Correct!    lag phase      log phase   Correct!    stationary phase   Correct!    death phase     Question 12  0 / 1 pts Assuming unlimited resources and space, which line from the graph on the right best depicts a thermophile grown at  50°C?    a     bu Answered    c     Question 13  0 / 1 pts Jo, a technician in a microbiology lab, is measuring the number of bacteria cells in a culture in the morning and again in the afternoon using serial dilutions and viable plate counts. Jo counted more colonies from the morning test than the afternoon test. What was the culture's growth phase that afternoon? Question authored by: Sammy You Answered    log      lag      stationary      death     Question 14  1 / 1 pts Mucus is found in nostrils and contains high amounts of protein, salt, sugar, and particulate matter from the air. Which group of bacteria would be most likely to grow in mucus?    Photosynthetic bacteria      Thermophilic bacteria      Acidophiles      Obligate anaerobes   Correct!    Halophiles     Question 15  1 / 1 pts The term microaerophile refers to an organism that    does not use oxygen but tolerates it.      is killed by oxygen.   Correct!    requires less oxygen than is present in air.      requires more oxygen than is present in air.     Question 16  1 / 1 pts Figure 6.3 Growth of two bacteria on normal and high salt nutrient agar The data in the table indicate that S. aureus is a(n)    mesophile.      facultative anaerobe.   Correct!    facultative halophile.      obligate halophile.      aerobe.     Question 17  1 / 1 pts Staphylococcus aureus is non-motile, a facultative anaerobe, and a mesophile. You place the S. aureus in a culture tube with all essential nutrients. How should you incubate the tube to produce the highest cell mass of S. aureus within two hours? Correct!    Flask with aeration and shaking at 37C.      Flask left on the lab bench at 20C.      Flask grown in an anaerobic chamber that removes oxygen from the air around the flask at 37C.      Flask without aeration at 50C.      Flask in a water bath with shaking at 90C.     Question 18  2 / 2 pts A chemostat is a bioreactor (vessel) to which fresh medium is continuously added, while culture liquid containing left over nutrients and waste products are continuously removed. How would growing a bacteria culture in a chemostat change the growth curve?    The cells in the culture would cycle through the four phases of the growth curve more quickly.      The cells in the culture would immediately begin logarithmic growth and skip the lag phase.   Correct!    The log phase of the growth curve would be extended.    The culture would have a smaller cell mass in comparison to an identical culture that was not grown in a bioreactor.     Question 19  0.67 / 2 pts A patient has recently developed a bacterial infection in the tissues surrounding their cardiac pacemaker. The patient's medical team is working fast to treat the infection before the bacteria can establish a biofilm on the surface of the pacemaker. Why will it be more difficult to treat the infection with antibiotics if the bacteria form a biofilm? Select all that apply.    The extrapolymeric substance (EPS) allows faster diffusion of antibiotics in the biofilm.   You Answered    Cells are more metabolically active at the base of a biofilm.      Cells are metabolically inactive in a biofilm.   Correct!    Bacteria in a biofilm readily exchange antibiotic resistance genes.   Correct!    Bacteria in a biofilm may have abilities that counteract the action of antibiotics      Biolfims are comprised of Gram negative bacteria that have natural resistance to antibiotics.     Question 20  2 / 2 pts How would a limited food supply affect the bacterial growth curve?    There would be no lag phase.   Correct!    The log phase would be shortened.      The culture would not enter a death phase but would remain stationary indefinitely.      The death phase would be shortened.      The slope of the log phase growth curve would be steeper.     Question 21  1 / 1 pts Hobie came into your office to discuss an illness he’s had for the last few days. Hobie says he feels lightheaded, has an aching stomach, and a pounding headache. You do a check up on Hobie and you see that he has shortness of breath, his face is flushed and he’s coughing pretty badly. What have you identified in this illness and what has Hobie identified? Question authored by: Ay'reese    You identified his symptoms and Hobie has identified his signs.      You and Hobie both identified his symptoms.   Correct!    You have identified Hobie’s signs and Hobie has identified his symptoms.      You don’t know and need Hobie to give you more information.     Question 22  1 / 1 pts The time between exposure to a pathogen and when symptoms begin is called the Question authored by: Jameson    prodromal period.      period of illness.      period of decline.   Correct!    incubation period.      period of convalescence.     Question 23  1 / 1 pts You have recently lost your sense of taste and smell so you decide to take a Covid test. Which of these is a sign that you have Covid-19?    loss of taste and smell   Correct!    positive Covid test result      negative Covid test result      your decision to get a Covid test      Both loss of taste and smell AND your decision to get a Covid test     Question 24  1 / 1 pts The 1918 Spanish flu virus pandemic was a result of a(n) _____ in which two flu strains recombined to create a very virulent influenza virus.        hemagglutinin spike   Correct!    antigenic shift      antigenic drift      transduction     Question 25  1 / 1 pts Why is an acute disease with a high mortality rate unlikely to spread through the population?    The number of microbes present in the host will remain low.      The infected individuals will have no and symptoms and will therefore avoid contact with others and not transmit the disease.      The microbes causing the disease are not contagious during the latent period.   Correct!    The disease develops and kills those infected rapidly so that there is little time for transmission.      The area of infection in the host is localized and therefore won’t spread to others easily.     Question 26  0 / 1 pts Each of these virulence factors increase pathogenicity of the microbe. Which of the factors would specifically influence the microbe's ability to evade host immune cells?        Staphylococcus aureus carriers are very susceptible to wound infection after undergoing surgery.      Clostridium perfringes spores can germinate deep within wounds, where they release a protein that moves along muscle fibers killing all host cells.   You Answered    Neisseria gonorrhea produces pili and adhesins specific to the human urogenital epithelium.      Many Streptococcus strains have a capsule layer outside of the cell membrane and cell wall.      Staphylococcus aureus can synthesize hemolysins.     Question 27  1 / 1 pts How does having a capsule increase the virulence of a bacterial cell?    A capsule gives bacteria antibiotic resistance.   Correct!    Bacteria with a capsule cannot be phagocytized by immune cells.      The capsule speeds up asexual reproduction of the bacteria.      The capsule increases bacteria motility.     Question 28  1.5 / 2 pts Diseases that involve biofilm-producing bacteria are not as easily treat compared to those caused by free-floating bacteria that don't form biofilms. Select all that explain why. Correct Answer    Bacteria in biolfilms are less affected by medication.      Bacteria in biofilms grow more slowly.      Biolfilms only occur in the hospital setting.   Correct!    The extra polymeric substance that coats biolfilms makes if difficult to deliver medications to bacteria inside the biofilm. Correct!    Bacteria in biofilms have abilities that help counteract medications.   Correct!    Horizontal gene transfer of resistance genes is commong among bacteria in biofilms.     Question 29  2 / 2 pts Select the statement that describes the period of illness stage in the course of infection and disease.    Relatively short stage that follows the incubation period.      The interval between initial exposure and the first appearance of signs or symptoms.   Correct!    The patient exhibits strong signs and symptoms of disease and disease is most severe.      The patient regains strength and the body returns to its predisease state.     Question 30  1 / 1 pts The incidence of typhoid fever in the US from 1954-2013 is shown in the graph below. During what span of time would the incidence of typhoid fever be considered a pandemic? Correct!    1954-1959      1954-1979      1969-1974      1954-1974     Question 31  1 / 1 pts The spread of disease by food over a distance greater than 1 meter is called ____transmission.    vector      direct      droplet   Correct!    vehicle     Question 32  1 / 1 pts A disease transmitted by a needlestick is an example of    direct contact.      droplet transmission.   Correct!    indirect contact transmission by fomite.      direct biological transmission by vector.      vehicle transmission.     Question 33  1 / 1 pts Only a living organism can be a reservoir of infection.    True   Correct!    False     Question 34  0.5 / 1 pts Typhoid Mary was infected with S. typhi and although she was asymptomatic, she spread the bacteria to other hosts by passing it in food she prepared. Mary was a human reservoir of S. typhi and spread typhoid fever by vehicle transmission. Answer 1: You Answered human   active carrier   Answer 2: Correct! vehicle     Question 35  1 / 1 pts In 1854 a cholera outbreak in London was caused by contamination of drinking water with the bacteria Vibrio cholerae and killed over 10,000 people. This is an example of disease transmission by    direct contact.      biological vector.      fomite.   Correct!    vehicle.      droplet.      indirect contact.     Question 36  1 / 1 pts Cholera is a disease that can spread when sewage mixes with drinking water. Cholera is spread by ____ transmission.    direct contact   Correct!    vehicle      fomite      biological vector      carrier     Question 37  2 / 2 pts Scenario 14.1 During a six-month period, 239 cases of pneumonia occurred in a town of 300 people as a result of Coxiella burnettii infections. Before the outbreak, 2000 sheep were kept 30 miles northwest of the town, 95% of sheep tested were positive for C. burnetii. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years. In situation 14.1 what is the incidence of pneumonia in humans for the six-month period?    300   Correct!    239/300 = 77%      95%      95% of 2000 = 1900      239/539 = 44%     Question 38  2 / 2 pts In the 1832 cholera outbreak in New York City 4,000 people were sick with cholera by July 1st and in the month of July another 1,000 people got sick. If the total population of NYC was 250,000, what was the incidence of cholera for the month of July?    4,000/250,000 or 1.6%   Correct!    1,000/250,000 or 0.4%      5,000/250,000 or 2%      3,000/250,000 or 1.2%   Question 1  1 / 1 pts All of the following occur during inflammation. What step occurs first?    Leukocytes follow chemotactic signals to move toward the area.      Macrophages phagocytize cellular debris.   Correct!    Chemical signals are released by pathogens and injured tissues.      Leukocytes squeeze through capillary walls at the site of injury.     Question 2  1 / 1 pts Which non-specific innate defense mechanism is mismatched with its associated body structure or body fluid?    Ciliated goblet cells produce mucous in the intestines to trap pathogens.      Lysozyme is present in mucus and tears and can destroy the peptidoglycan in the bacterial cell wall.   Correct!    Complement proteins present in the urine can initiated the destruction of pathogens.      Tight cell connections in the skin keep most pathogens from entering the host.      Ear wax, skin, and the vagina all have a slightly acidic pH that prevents the growth of many pathogens.     Question 3  1 / 1 pts How does a phagocyte “know” it is in contact with a pathogen instead of another body cell?    Pathogens have capsules that phagocytes can adhere to.    Phagocytes are not able to distinguish body cells (self) from pathogens (non-self) and destruction happens at random. Correct!    Phagocytes recognize Pathogen-Associated Molecular Patterns (PAMPs) on the surface of pathogens.    The pathogen is packaged in the phagosome by immune cells so the phagocyte can bind to it and engulf it.      The phagocyte detects enzymes released by the pathogen.   Question 4  0 / 1 pts How many of the items listed below are part of the innate immune response? phagocytosis inflammation antibody production complement cascade fever    5      4      1   You Answered    3      2     Question 5  1 / 1 pts A new wound infected with MRSA causes an immune response with inflammation. There is a a brief period of vasoconstriction followed by vasodilation of the vessels near the wound. Vasoconstriction occurs in order to Correct!    minimize blood loss from the wound.      increase vessel permeability.      dilute toxins and bacterial products at the wound site.      bring immune cells to the wound.     Question 6  1 / 1 pts A child falls and suffers a deep cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will try to eliminating contaminating microbes immediately?      skin cells of the epidermis sloughing off      hair follicles and sweat glands      production of endotoxin   Correct!    phagocytosis and the inflammatory response      production of antibodies     Question 7  1 / 1 pts Dendrites and macrophages are immune cells that are capable of _____.    clotting.      producing antibodies.   Correct!    phagocytosis.      inflammation.     Question 8  1 / 1 pts How does the ciliary escalator function to eliminate microbes from the host organism?    Peristalsis sends microbes to the lung aveoli where they are killed.      The escalator recruits inflammatory cells to the respiratory tissues.   Correct!    Microbes are trapped in mucus secretions and moved towards the throat by cilia.      Cilia use digestive enzyme to kill microbes.     Question 9  0 / 2 pts True or False: All of the descriptions below are part of the innate immune system. connections between skin cells physically prevent microbes from entering the host lysozyme present in perspiration can degrade bacterial cell walls lysozyme present in perspiration can degrade bacterial cell walls mucous membranes secrete mucus that traps microbes B lymphocytes produce antibodies against microbial antigens phagocytes adhere to invading microbes and destroy them You Answered    True     False     Question 10  1 / 2 pts A patient has a lesion on their thigh that is infected with MRSA. MRSA bacteria are coated in a capsule and are able to survive in the cytoplasm of the phagocyte to prevent their destruction by phagocytosis. Which steps in phagocytosis are MRSA able to inhibit? Correct!    formation of the phagolysosome      adherence      release of debris      chemotaxis     Question 11  2 / 2 pts Select all of the following that would either enhance or reduce a phagocyte’s ability to bind to a microbe. Correct!    Initiation of the complement cascade results in the microbe being coated in the complement protein C3b.   Correct!    A DNA mutation that causes alteration in the phagocyte’s Pathogen Recognition Receptors.      The microbe is an enveloped virus.   Correct!    The microbe aquired the ability to make a capsule.     Question 12  1 / 2 pts Activation of the complement cascade may result in which of the following? (Select all that are correct)    reduced blood vessel permeability.   Correct!    lysis of the pathogen.   Correct!    inflammation.   You Answered    apoptosis of infected cells.      antibody production.     Question 13  1 / 1 pts In general, what sorts of pathogens may be able to more successfully attack a patient with an inability to synthesize B lymphocytes?      Viruses      Intracellular antigens   Correct!    Extracellular antigens      Large pathogens with repeating structures     Question 14  1 / 1 pts Your patient has an infected wound on their foot causing them pain and a high fever. Blood work is done on the patient and their levels of IgM antibody are very high. What can you conclude from this piece of data? Correct!    The infection is recent.      The infection is a result of normal microbiota that have become pathogenic.      Nothing, high levels of IgM in the blood is normal.      The infection is caused by a virus.     Question 15  1 / 1 pts The antibodies found in mucus, saliva, and tears are Correct!    IgA      IgE      IgM      IgG     Question 16  1 / 1 pts The most abundant class of antibodies in serum is    IgE      IgD      IgM   Correct!    IgG      IgA     Question 17  1 / 1 pts The most abundant class of antibodies in serum is    IgM      IgD      IgE   Correct!    IgG      IgA     Question 18  1 / 1 pts What does an antigen bound to MHC I on the surface of a cell indicate about that cell?    The cell has encountered an exogenous antigen.      The cell is displaying the antigen for a helper T cell to recognize.   Correct!    The cell is infected with an endogenous antigen.      The cell is a plasma cell and is making antibodies.     Question 19  1 / 1 pts T cells are responsible for directly manufacturing antibodies.     True   Correct!    False     Question 20  1 / 1 pts A man develops a respiratory infection caused by a virus. He is not given antibiotics and subsequently recovers after about two weeks. Which best explains why his body destroyed some of his own cells during the viral infection?    Most viruses transform normal cells into cancer cells that use up available nutrients, causing cell death.   Correct!    Viral proteins are intracellular antigens that are bound to MHCI molecules and presented to cytotoxic T-lymphocytes that lead to destruction of the infected cell.      Antibodies are able to coat the viruses before they are able to absorb to host cells, resulting in the death of host cells.      Certain types of phagocytes in the body are able to penetrate virus-infected cells in order to seek out and engulf viruses.      The complement cascade is initiated by viral proteins in the host and ultimately results in the death of host cells.     Question 21  1 / 1 pts What type of immunity results from vaccination? Correct!    artificially acquired immunity      innate immunity      passive immunity      naturally acquired immunity     Question 22  1 / 1 pts Active immunity will last longer than passive immunity. Correct!    True      False     Question 23  1 / 1 pts Which of the following contribute to the specificity of adaptive immunity?    T cells release cytokines that control many aspects of adaptive immunity.      B cells can be activated to become memory cells capable of handling a repeated infection.   Correct!    Each B and T cell has a unique receptor that recognizes antigen.      T or B cells mature in the thymus or bone marrow and then circulate through the body.     Question 24  0.5 / 1 pts Which of the following statements about B cells are TRUE?    In response to antigen, all B cells located close to the antigen begin dividing.In response to antigen, all B cells located close to the antigen begin dividing.   Correct!    Each B cell is programmed to make one specific type of antibody.    B cells have B-cell receptors, MHCI, and MHCII on their surface.   Correct!    The B-cell receptor allows B cells to detect antigen.      An activated B cell called a plasma cell makes and secretes antibody.     Question 25  1 / 1 pts Autoimmune disorders are characterized by immune destruction of self tissues. The underlying basis of these disorders is    an overproduction of complement.      failure to produce memory cells.   Correct!    failure to delete B and T cells that are reactive to self antigens.      an oversecretion of antibodies from memory B cells.     Question 26  0 / 1 pts Your neighbor’s child has been diagnosed with a disease that causes the child to make no antibodies. Which of the following functions is this child still able to perform at normal levels?   You Answered    Increase the activity of phagocytic cells.      Stop viruses from binding to cells.      Antibody-dependent cell-mediated cytotoxicity   Correct Answer    Activate cytotoxic T-lymphocytes that kill infected cells.      Stop toxins from damaging host tissues.     Question 27  1 / 1 pts Both are components of adaptive immunity but         [ Select ]      ["adaptive", "humoral", "innate", "cell-mediated"]  immunity depends on B cells and         [ Select ]      ["innate", "humoral", "adapative", "cell-mediated"]  immunity depends on T cells. Answer 1: Correct! humoral   Answer 2: Correct! cell-mediated     Question 28  1 / 1 pts M. tuberculosis can stay in the extracellular space of the lungs or can reside inside the cytoplasm of a human macrophage cell there. Which of these forms of M. tuberculosis infection would be targeted by CD8+ cytotoxic T cells? Correct!    M. tuberculosis inside a macrophage    Either form of M. tuberculosis infection    Neither form of M. tuberculosis infection    M. tuberculosis in the extracellular space   Question 29  1 / 1 pts Newborn immunity resulting from the transfer of antibodies across the placenta is Correct!    naturally acquired, passive immunity.      artificially acquired, active immunity.      innate immunity.      naturally acquired, active immunity.     Question 30  1 / 1 pts B cells, macrophages, and dendritic cells differ from other human cells in that they express ______ on their surface.    CD8 receptors      CD4 receptors   Correct!    MHC-II receptors      interleukin-2      MHC-I receptors     Question 31  1 / 1 pts How is a T-cell receptor different from a B-cell receptor? Correct!    T-cell receptors must have antigen broken down inside a cell and presented to them by a Major Histocompatibility Complex (MHC) molecule.    T-cell receptors are attached to the cell surface.    T cell receptors have a variable region that binds to a unique epitope.    T-cell receptors from different T cells recognize different antigens.   Question 32  1 / 1 pts Which of the cells listed below can present extracellular antigens on Class II MHC proteins?    B cells      Healthy epithelial cells   Correct!    B cells or macrophages      Macrophages      Virus-infected epithelial cells     Question 33  0 / 1 pts B cells are activated by _____ to become plasma cells. You Answered    an antigen presented on MHC      an antigen-presenting cell      a memory cell      an antibody      cytokines released by a CD4+ T cell     Question 34  1 / 1 pts What happens when a B-cell receptor binds an self/autoantigen in the bone marrow? The B-cell Correct!    undergoes apoptosis (cell death).      proliferates (divides).      develops into a memory cell.      develops into a plasma cell.      produces antibodies.     Question 35  0 / 2 pts An interaction between two cells is shown in the figure. MHCI on the surface of Cell 1 is interacting with a T cell receptor on the surface of Cell 2. Identify the immune cells.    cell 1: Antigen-Presenting Cell, cell 2: B cell      cell 1: nucleated cell, cell 2: CD8 T cell   You Answered    cell 1: Antigen-Presenting Cell, cell 2: CD4 T cell      cell 1: Antigen-Presenting Cell, cell 2: phagocyte     Question 36  0 / 2 pts Select all of the TRUE statements about antigen presentation of intracellular and extracellular antigens. Correct Answer    Intracellular antigens are inside a host cell but extracellular antigens are outside and must be brought into the host cell.   Correct!    Intracellular antigens are presented on MHC I proteins but extracellular antigens are presented on MHC II proteins.      Cytotoxic T cells recognize intracellular antigens but helper T cells recognize extracellular antigens.   You Answered    A small portion of intracellular antigen is displayed on the cell surface but the entire extracellular antigen is displayed on the cell surface.     Question 37  2 / 2 pts Why does antibody concentration fade over time with passive immunotherapy but increase over time with active immunotherapy? Select all that apply.    Active immunotherapy is acquired by artificial means and is more concentrated.   Correct!    Active immunotherapy is exposure to antigen and the person’s own immune system make antibodies in response.   Correct!    Passive immunotherapy is gaining antibodies directly and they can break down over time.     Question 38  2 / 2 pts Scientists can develop genetically modified strains of mice. Describe the immunological impairments that mice deficient in MHCI or in MHCII would have. Correct!    Mice deficient in MHCI would be unable to present intracelluar antigens to T cells while mice deficient in MHCII would be unable to present extracellular antigens to T cells.      Mice deficient in MHCI would be unable to present extracellular antigens to T cells while mice deficient in MHCII would be unable to recognize self.      Mice deficient in MHCI would unable to recognize antigens and produce antibodies while mice deficient in MHCII would have dysfunctional cytotoxic T.      Mice deficient in MHCI and MHCII would both be unable to phagocytize invading pathogens.      Mice deficient in MHCI would be unable to phagocytize invading pathogens and mice deficient in MHCII would be unable to recognize self.     Question 39  2 / 2 pts All of the following events occur to elicit an antibody response. Put them in the order they occur from step 1 to step 5. Correct! Step 1                  The Antigen-Presenting Cell phagocytizes antigen              Correct! Step 2                  Part of the digested antigen is presented on the surface of the Antigen-Presenting Cell              Correct! Step 3                  The helper T cell recognizes antigen-digest bound to MHC II              Correct! Step 4                  The helper T cell produces cytokines              Correct! Step 5                  B cell is activated