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MIC Practice Test Questions for Exam 2|194 Questions with
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Later in infection once it had traveled to the lymph node, Yersinia pestis, switches strategy and starts to a. It releases a toxin that causes the surround tissue to become very salty. b. It makes an altered form of LPS that has reduced binding to TLRs. c. It stops making LPS so not to activate toll like receptors (TLRs). d. It uses a protein injection system to paralyze immune cells. - CORRECT ANSWER It makes an altered form of LPS that has reduced binding to TLRs. Your lab partner Ricky is accusing you of not properly culturing the bacterium in a test tube containing liquid media (see accompanying photograph). Why else, Ricky asks, would this bacterium not be able to grow near the top edge of the liquid media; thereby implying that you didn't shake the tube when you inoculated the tube the day before. What do you tell your obnoxious lab partner? a. That this pattern of growth is characteristic of a microaerophilic microbe. b. That this pattern of growth is characteristic of a facultative anaerobic microbe. c. That this pattern of growth is characteristic of an obligate anaerobic microbe. d. That he's correct, you likely did make a mistake because something is obvious wrong. - CORRECT ANSWER That this pattern of growth is characteristic of an obligate anaerobic microbe. Which type of immune response is not protective in clearing helminth infections in the gastrointestinal tract? a. TH1-derived cytokines b. antibody-dependent cell-mediated cytotoxicity (ADCC) c. mast activation d. production of IgE antibodies - CORRECT ANSWER antibody-dependent cell- mediated cytotoxicity (ADCC)
Mitochondrial-derived _____ activate an immune response that is similar to immune responses activated by bacterial derived _____. a. PAMPs (MAMPs) ; DAMPs b. DAMPs ; PAMPs (MAMPs) c. DAMPs ; DAMPs d. PAMPs (MAMPs) ; PAMPs (MAMPs) - CORRECT ANSWER DAMPs ; PAMPs (MAMPs) All of the statements about antibiotic resistance in bacteria are true EXCEPT: a. Antibiotic resistance has existed long before the emergence of modern humans. b. Bacteria can become antibiotic resistant in several different ways. c. There is no need to search for new antibiotics since we now have complete knowledge of how bacteria become resistant to antibiotics. d. Essentially identical antibiotic resistance genes are found in soil and clinical bacterial species. - CORRECT ANSWER There is no need to search for new antibiotics since we now have complete knowledge of how bacteria become resistant to antibiotics. All of the following are true statements about yeast-mediated ethanol production EXCEPT: a. Yeast do not possess the enzymes to break down starch; these enzymes are made in the germinating barley seed. b. ATP is produced by both substrate-level and oxidative phosphorylation. c. Acetaldehyde serves as a terminal electron acceptor. d. The ethanol produced is actually an excretion product. - CORRECT ANSWER ATP is produced by both substrate-level and oxidative phosphorylation. What is the definition of 'antibiotics'? a. Antimicrobial compounds that can be ingested or injected into animals with minimal side effects. b. Antimicrobial compounds applied to inanimate objects. c. All of the answers, depending on the context, can be true.
d. It is a polymer composed of nucleic acids. - CORRECT ANSWER It is the information storage molecule. The following symptoms are characteristic of an inflammation caused by a localized infection EXCEPT a. Swelling b. Pain c. Fever d. Redness - CORRECT ANSWER Fever Which of the pairs below portrays a barrier function that was breached by the indicated pathogen prior to the infection? a. Antimicrobial molecules produced by the skin - Vibria cholera b. Action of lysozyme in tears - HIV c. Mucociliary escalator - influenza d. Stomach acidity - Yersinia pestis - CORRECT ANSWER Mucociliary escalator - influenza Why were gut microbes once referred to as 'commensals'? a. It was thought that there was little variation between humans. b. Because their abundance was based on CFU assay and thus was vastly underestimated. c. It was thought that our knowledge of its species composition was fairly complete. d. It was thought that they in no way impacted our health. - CORRECT ANSWER It was thought that they in no way impacted our health. An INCORRECT statement about polio virus - CORRECT ANSWER The disease is acquired via the urogenital tract The discovery of antibiotics in the _______ was totally ________. a. 1920s ; unexpected b. 1960s ; expected
c. 1960s ; unexpected d. 1920s ; expected - CORRECT ANSWER 1920s ; unexpected The plague bacterium, Yersinia pestis, infects humans via the bite of a flea. How does this pathogen prevent an aggressive inflammatory response at this initial point of infection? a. It stops making LPS so not to activate toll like receptors (TLRs). b. It makes an altered form of LPS that has reduced binding to TLRs. c. It releases a toxin that causes the surrounding tissue to become very salty. d. It uses a protein injection system to paralyze immune cells. - CORRECT ANSWER It makes an altered form of LPS that has reduced binding to TLRs. In the early phase of infection immediately following gaining access to the tissue (i.e., just after the flea bite), how does Yersinia pestis avoid getting killed by the resident macrophages? a. It invades these macrophages and immediately kills them. b. It releases a toxin that kills macrophages and other immune cells. c. It invades these macrophages but avoids being exposed to the contents of the lysosome. d. It uses a protein injection system to paralyze these macrophages. - CORRECT ANSWER It invades these macrophages but avoids being exposed to the contents of the lysosome. Which HIV-infected individuals carry the highest risk to transmit HIV? a. Heterosexual women during sexual contact b. Pregnant women during birth c. Heterosexual men during sexual contact d. Homosexual men during sexual contact - CORRECT ANSWER Pregnant women during birth Which description is correct for activated CD8+ T-cells? a. Their secondary function is to inhibit macrophages and local inflammation. b. They release molecules onto virally infected cells to kill them.
E. coli, as well as many other organisms including humans, possess an enzyme, Isocitrate Dehydrogenase, which performs a key reaction in the Krebs cycle. The E. coli gene encoding this enzyme... a. ...has only been identified through its corresponding transcribed RNA. b. ...has been identified in the E. coli genome, but its exact DNA sequence has not been determined. c. ...has been identified in the E. coli genome and its exact DNA sequence is available in public databases. d. ...has so far not been identified in the E. coli chromosome. - CORRECT ANSWER ...has been identified in the E. coli genome and its exact DNA sequence is available in public databases. All of the following are true statements about the 'germ theory of fermentation' and the 'germ theory of disease' EXCEPT: a. The 'germ theory of fermentation' proceeded the 'germ theory of disease' by approximately 20 years. b. Louis Pasteur was involved in formulating and establishing both theories. c. They were totally independent of one another in terms of practical experimental techniques. d. Both ideas were counter-intuitive for many scientists and most non-scientists of the day. - CORRECT ANSWER They were totally independent of one another in terms of practical experimental techniques. When brewing beer in a bucket, a water-filled air lock is required to allow _________ to escape and to prevent ________ from entering. a. Ethanol : O b. CO2 : O c. CO2 : acetic acid bacteria d. O2 : CO2 - CORRECT ANSWER CO2 : O What is a unique ability of the adaptive immune system that the innate immune system cannot provide?
a. It has "millions" of cells waiting in the body to become activated by the pathogen. b. It kills pathogens. c. It generates immunological memory. d. Cells are recruited to the site of an infection. - CORRECT ANSWER It generates immunological memory. Regarding rabies virus a. In the USA, the main source are mice b. It spreads in the body after infection via the bloodstream c. When the virus reaches the central nervous system and the symptoms of the disease are apparent, is almost always fatal d. A live virus vaccine is required to be given to all children of school age - CORRECT ANSWER When the virus reaches the central nervous system and the symptoms of the disease are apparent, is almost always fatal T-cells and B-cells usually do not cause autoimmunity, e.g., they do not attack our own healthy cells ("self"). Nevertheless, the specificities of their antigen receptors are randomly generated. How come? - CORRECT ANSWER Self-reactive T-cells and B-cells are removed early during their development in the thymus and, respectively, in the bone marrow. What is the major function of B-cells as compared to T-cells? - CORRECT ANSWER B-cells secrete antibodies while T-cells kill infected cells or provide help to other cells of the immune system. In which organ do CD4+ T-cells and CD8+ T-cells diverge from their common precursor? a. Thymus b. Lymph node c. Spleen d. Bone marrow - CORRECT ANSWER Thymus The immunological recognition of danger by pattern recognition involves the following concepts and mechanisms EXCEPT - CORRECT ANSWER It triggers immunological defense functions after a delay of one to two weeks.
c. Generate metabolic energy d. Do not cause human disease - CORRECT ANSWER Are composed solely of protein Regarding Arboviruses all of the following statements are true EXCEPT a. Their natural hosts (reservoirs) can be birds b. Are usually transmitted by mosquitoes and ticks c. Include dengue, Zika and yellow fever viruses d. They are DNA containing viruses - CORRECT ANSWER They only produce mild symptoms even after the viruses spread twice in the body by viremia OR They are DNA containing viruses Many vaccines work by eliciting antibodies (Abs) to protect us by the following mechanisms EXCEPT: a. Abs can block the entry of microorganisms through mucosal barriers. b. Abs can opsonize microorganisms for their phagocytosis and destruction by macrophages. c. Abs can block the activity of bacterial toxins. d. Abs can inhibit complement activation by pathogens. - CORRECT ANSWER Abs can block the entry of microorganisms through mucosal barriers. Many vaccines work by eliciting pathogen-specific antibodies that will circulate in our bodies to protect us from later infections with the pathogen. These antibodies are protective because, among other abilities, - CORRECT ANSWER they neutralize the pathogen or toxin by preventing it from binding to its receptors on the host cells Why is the somatic recombination of V, D, J segments in our bone marrow and thymus important? This process - CORRECT ANSWER generates nearly unlimited antigen specificities for T-cells and B-cells in an individual
Complement proteins have many functions but they CANNOT - CORRECT ANSWER recognize specific antigens of infectious pathogen A 3-year-old girl is diagnosed for a second time with a life threatening meningitis. The pathogen isolated in both cases is Neisseria Meningitis (meningococcus). Other than that, the girl has been healthy until now. What describes this situation best? The second incident - CORRECT ANSWER should alert the health professionals to an inborn complement deficiency or complement dysfunction in their young patient. Which statement is correct? - CORRECT ANSWER So called NETs and pus can act as traps for other microorganisms trying to colonize an infection. Nitrogen is an important component of DNA and proteins and there's plenty of nitrogen in the air. However, atmospheric nitrogen (in the form of N2) must be chemically reduced ('fixed') before it can be incorporated into DNA and proteins. All of the following statements about the chemical reduction of N2 are true EXCEPT: a. The industrial reduction of N2 to NH3 requires extremely high temperatures and pressures. b. Bacteria within plant root nodules reduce N2 to NH3. c. Nitrogenase is the bacterial enzyme that reduces N2 to NH3. d. The intestinal microbiota of humans reduce N2 to NH3. - CORRECT ANSWER The intestinal microbiota of humans reduce N2 to NH3. Which situation describes an example for passive immunization? a. Second application (booster) of the DPT vaccine (diphtheria, pertussis/whooping cough, and tetanus; the vaccine components include diphtheria and tetanus toxoids and killed whole cells of the bacterium that causes pertussis). b. Activating dendritic cells of a cancer patient outside the body with tumor antigens prior to returning them to the patient. c. Injection of antibodies from an Ebola survivor into a patient that just contracted Ebola.
b. Hepatitis B only causes mild disease all over the world c. Hepatitis D is a viroid-like agent containing RNA d. There is no vaccine available against any Hepatitis virus - CORRECT ANSWER Hepatitis D is a viroid-like agent containing RNA Many commonly used antibiotics inhibit protein synthesis in bacteria. All of the following are true statements about this general class of antibiotics EXCEPT: a. They target different regions of the bacterial ribosome; but all inactivate its function. b. Bacteria can develop resistance to this class of antibiotics. c. Most antibiotics were first identified in soil bacteria. d. These antibiotics exclusively bind bacterial (prokaryotic) ribosomes; not to human (eukaryotic) ribosomes and therefore can be used at extremely high doses. - CORRECT ANSWER These antibiotics exclusively bind bacterial (prokaryotic) ribosomes; not to human (eukaryotic) ribosomes and therefore can be used at extremely high doses. What is the major function of B-cells? a. B-cells fight pathogens residing in the extracellular space. b. B-cells kill infected cells. c. Activated B-cells travel to the site of an infection to limit is local progression. d. B-cells fight infections in the bone marrow to preserve its hematopoietic stem cells. - CORRECT ANSWER B-cells fight pathogens residing in the extracellular space. T-cells and B-cells recognize antigens differently because a. TCRs, but not BCRs, need to recognize the antigen in the context of an MHC molecule. b. antigens need to undergo the process of antigen presentation to be recognized by T-cells, but not by B-cells. c. BCRs, but not the TCRs, can recognize polysaccharides d. All of the answers - CORRECT ANSWER ***
TCRs, but not BCRs, need to recognize the antigen in the context of an MHC molecule Strictly in terms of obtaining energy, what plays the primarily role in determining the microbial composition of a particular environment? a. Electron donors and acceptors b. Atmospheric pressure c. Temperature d. Water content - CORRECT ANSWER Electron donors and acceptors Your roommate Alex is really into genetics and computers. In analyzing antibiotic resistance genes of hundreds of microbes he makes a startling discovery: that soil-inhabiting bacteria and bacteria that cause human diseases (like Staphylococcus aureus) have in many cases can have IDENTICAL antibiotic- resistance genes despite the fact that the groups of bacteria are very distantly related. What would you tell Alex? a. That there has to be a mistake in the data bases because it just is not possible. b. That it is true, because these genes mutate much more slowly than other genes. c. That it is true, but microbiologists have no idea why. d. That it is true, because these genes can be transferred between species by bacterial viruses ('phages') - CORRECT ANSWER That it is true, because these genes can be transferred between species by bacterial viruses ('phages') Which tissue comprises an immunological barrier? a. Gut mucosa b. Pancreas (organ secreting enzymes to digest food) c. Blood d. Retina (inner most layer of cells of the eye that initiate our vision) - CORRECT ANSWER Gut mucosa In regards to the AIDS epidemic, a monumental event occurred in 1987. That was the year that...
The influenza flu virus a. uses its hemagglutinin protein to bind to host cells and infect them. b. has its genomic information organized within a circular plasmid inside its nucleocapsid. c. causes minor disease symptoms as compared to other viruses that infect the respiratory tract. d. uses its hemagglutinin protein to infect red blood cells. - CORRECT ANSWER uses its hemagglutinin protein to infect red blood cells. OR infects cells after "holding on" to specific sialic acid modifications of molecules on cells of the respiratory epithelium. Recall that hemagglutination, or the lack thereof, can be used in various permutations for many diagnostic tests. With respect to an influenza virus infection, the ability to agglutinate red blood cells is caused by - CORRECT ANSWER hemagglutinin spikes on the viral envelope How is it possible that individuals with an intact innate and adaptive immune system can be infected by influenza viruses within a year after their prior influenza infection rather than being immune following the first infection? - CORRECT ANSWER Usually the viruses change the structure just enough so that they escape the antibodies raised against the prior infection. All of the following statements about Chlamydia trachomatis are true EXCEPT: a. C. trachomatis exists in two forms: an infectious elementary body (EB) and a reticulate body (RB). b. In females C. trachomatis infection is often asymptomatic. c. EB can only grow outside of animal cells. d. RB can only grow inside animal cells. - CORRECT ANSWER EB can only grow outside of animal cells. Each antibody molecule has ____ identical binding sites.
a. four b. two c. one d. three - CORRECT ANSWER two Which of the following explains why immunity to influenza may appear to be relatively short-lived? a. Immune responses to influenza involve innate immune mechanisms only b. Influenza virus kills memory T cells c. New influenza variants able to escape previous immunity appear regularly d. Effective immunological memory fails to develop - CORRECT ANSWER New influenza variants able to escape previous immunity appear regularly Regarding Arboviruses all of the following statements are true EXCEPT a. Their natural hosts (reservoirs) can be birds b. Include dengue, Zika and yellow fever viruses c. Are usually transmitted by mosquitoes and ticks d. They are DNA containing viruses - CORRECT ANSWER They are DNA containing viruses Which pair below fulfills all of the following: 1) It only comprises cells or weapons of the innate immune system; 2) The first cells or weapons participate in the defense of viral infections; and 3) The second cells or weapons participate in the defeat of bacterial infections. a. interferon alpha - B-cells/antibodies b. cytotoxic T-cells - interferon alpha c. macrophages - neutrophils d. NK cells - macrophages - CORRECT ANSWER NK cells - macrophages Biological characteristics of interferons include all of the following EXCEPT - CORRECT ANSWER virus specific Viruses are distinguished from bacteria because they
a. "plugg" the holes of an injured barrier. b. recognize bacterial products such as LPS. c. migrate to the draining lymphnodes. d. take up bacterial pathogens and digest them. - CORRECT ANSWER "plugg" the holes of an injured barrier. The progression of an HIV infection to AIDS is controlled by many parameters. The following mechanisms and genes participate EXCEPT: a. Certain HLA alleles impair or enhance the progression. b. Induction of broadly neutralizing antibodies impairs the progression. c. Results from infected sooty mangabee monkeys indicate a strong immune response accompanied by strong inflammation can sterilize the infection. d. Lower levels of CCR5 impair the progression. - CORRECT ANSWER Results from infected sooty mangabee monkeys indicate a strong immune response accompanied by strong inflammation can sterilize the infection. The following characteristics describe the receptors of the adaptive immune system (TCRs and BCRs) EXCEPT: a. Their diversity exceeds trillions of different receptors. b. TCRs and BCRs are generated by the same molecular mechanism (VDJ recombination), but they use their own separate gene segments. c. Receptors with different specificities are present on a single cell to enable it to defeat different pathogens. d. Their diversity is established in the bone marrow (BCR) and, respectively, the thymus (TCR). - CORRECT ANSWER Receptors with different specificities are present on a single cell to enable it to defeat different pathogens. In terms of energy, both electrical devices like light bulbs and biological systems, like humans, rely on high energy electrons. All of the following statements about light bulbs and/or humans are also true EXCEPT: a. Light bulbs obtain their high energy electrons through a wire; humans obtain their high energy electrons from food. b. Light bulbs also use a wire to 'dispose' of (i.e., get rid of) their low energy electrons.
c. Humans use nitrate (NO3-) to 'dispose' of (i.e., get rid of) their low energy electrons. d. Light bulbs convert the energy from high energy electrons into heat (~light); whereas humans use high energy electrons primarily to make ATP. - CORRECT ANSWER Humans use nitrate (NO3-) to 'dispose' of (i.e., get rid of) their low energy electrons. Blood of a 7-year-old boy from central Africa, recently adopted by a couple in Kentucky, is drawn because he reports of repeated "cramping in my tummy." What result would you anticipate if the child would be infected by parasites in his gut? a. Elevated number of CD8+ T-cells b. Reduced number of CD4+ T-cells c. Elevated number of neutrophils d. Elevated number of eosinophils - CORRECT ANSWER Elevated number of eosinophils Macrophages can perform many functions. However, they CANNOT a. recognize pathogen-associated molecular patterns such as lipopolysaccharide (LPS). b. take up bacterial pathogens and digest them. c. secrete cytokines and chemokines to initiate an inflammation. d. "remember" a pathogen and attack it more viciously the second time. - CORRECT ANSWER "remember" a pathogen and attack it more viciously the second time. In the last 10 years, a consensus among microbiologists has emerged that the two most abundant groups of microbes present in the human gut, _________ and _________, should be considered the 'good guys' whereas, _________, which are much less abundant, should nevertheless be classified as the 'bad guys'. a. Gram positives; Gram negatives; viruses b. Proteobacteria; Bacteroidetes; Firmicutes c. Gram positives; viruses; Gram negatives
