BIOL 334 MICRO UNIT 5 (MC) EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026

BIOL 334 MICRO UNIT 5 (MC) EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026 Standard microbiological practices include all of the following EXCEPT ________. - Answers work space should be disinfected only when contaminating spills occur Which of the following is not a guideline on selection, collection, and handling of clinical specimens? - Answers A small quantity of specimen should be obtained. Which of the following tests can be used to distinguish Escherichia from Enterobacter? - Answers IMViC The clinical microbiology laboratory can provide preliminary identification of microorganisms based on ________. A) microscopic examination of specimens B) growth or biochemical characteristics C) immunologic techniques that detect microbial antigens D) All of the choices are correct. - Answers All of the choices are correct. Which of the following can be examined with an ordinary bright-field microscope? A) Wet mounts B) Heat-fixed specimens C) Chemical-fixed specimens D) All of the choices are correct. - Answers All of the choices are correct. Ten percent Calcofluor white stain is often used in wet mounts of ________. - Answers Molds 8) In the clinical laboratory, which of the following is (are) used as a rapid method of identification? A) Manual biochemical kit systems B) Mechanized/automated systems C) Immunologic systems D) All of the choices are correct. - Answers All of the choices are correct. An example of miniaturized commercial rapid bacterial identification system based on biochemical analysis is the ________. - Answers API 20E system Which of the following media will permit the growth of one group of bacteria while inhibiting the growth of some other groups? - Answers Selective The most common method used by clinical microbiology labs for identifying bacteria are ________. - Answers biochemical Which of the following is useful in the identification of bacteria? A) Source of the culture specimen B) Growth patterns on selective and differential media C) Hemolytic, metabolic, and fermentative properties D) All of the choices are correct. - Answers All of the choices are correct. The immunologic technique involving the transfer of proteins separated by electrophoresis to nitrocellulose sheets is ________. - Answers Immunoblotting Which of the following uses red blood cells? - Answers Hemagglutination inhibition Which of the following tests is an agglutination test for syphilis? - Answers Rapid Plasmin Reagin test Detection of single or multiple microorganisms based on their cytometric parameters is known as ________. - Answers flow cytometry The immunological reaction that occurs when there is an optimal ratio of antigen and antibody, producing a lattice at the zone of equivalence is known ________. - Answers Immunoprecipitation A colorless substrate acted on by the enzyme portion of the ligand to produce a colored product is known as a/an ________. - Answers Chromogen Of the scientific disciplines listed, which is the least directly relevant to the study of clinical microbiology? - Answers Ecology Clinical microbiologists diagnose some diseases by detecting and measuring the specific host response to the infection. What subdiscipline encompasses these methods? - Answers Immunology All of the following methods are employed to identify pathogens in clinical specimens EXCEPT ________. A) special stains and microscopy B) culture on a variety of all-purpose, selective, and/or differential media C) biochemical tests D) molecular testing for nucleic acids E) immunoassays F) There are no exceptions here. All of these methods are used to identify pathogens - Answers There are no exceptions here. All of these methods are used to identify pathogens Which of the following factors are considered during the risk assessment process for creating a safe microbiology laboratory? (Check all that apply.) A) Experience of the individuals working in the lab B) Infectious agent risk groups C) Types of procedures to be performed with the infectious agents D) Cost of personal protective equipment - Answers A) Experience of the individuals working in the lab B) Infectious agent risk groups C) Types of procedures to be performed with the infectious agents Which infectious agent risk group would Mycobacterium tuberculosis be placed in? - Answers Risk group 3 Staphylococcus aureus and Streptococcus pyogenes are in which risk group? - Answers 2 All of the following would be appropriate for handling routine patient specimens (urines, sputums, wound swabs) for microscopy and culture EXCEPT ________. A) gloves B) lab coat C) full-body positive pressure suit with air supply D) biological safety cabinet E) appropriate waste decontamination - Answers full-body positive pressure suit with air supply You are developing an ELISA test to detect cysts of a parasitic protozoan in stool specimens. Select the following items that would be part of this test. (Check all that apply.) A) Enzyme-labeled antibody against the parasite B) Enzyme-labeled rabbit anti-human-IgG antibody C) Microtiter plate containing wells coated with antibody against the parasite D) Chromogenic enzyme substrate E) Patient specimens - Answers A) Enzyme-labeled antibody against the parasite C) Microtiter plate containing wells coated with antibody against the parasite D) Chromogenic enzyme substrate E) Patient specimens Patients are instructed to collect sputum specimens in such a way as to minimize contamination with normal microbiota from the mouth. A sputum specimen has arrived in the clinical laboratory and a Gram-stained smear of the specimen reveals a mixture of Gram-positive cocci, Gram-negative cocci, and Gram-positive bacilli as well as numerous squamous epithelial cells. This result indicates ________. - Answers a poor quality specimen of primarily saliva and oropharyngeal microbiota A growth medium used for the recovery of fungal isolates from patient specimens contains antibiotics to prevent the overgrowth of bacteria and cycloheximide to prevent the growth of saprophytic fungi. This medium would be categorized as ________. - Answers Selective A patient specimen was Gram-stained upon arrival in the clinical laboratory and revealed both Gram-positive cocci and Gram-negative bacilli. The specimen was cultured on sheep blood agar and chocolate agar, and after incubation, the culture grew only the Gram-negative bacilli. Which of the following is/are a likely explanation(s) for the failure of the Gram-positive cocci to grow? A) The Gram-negative bacilli may have grown very quickly and overgrew the slower growing Gram-positive cocci. B) The media used may not support the growth of the Gram-positive cocci. C) The growth temperature may have enabled the growth of the Gram-negative bacilli but not the growth of the Gram-positive cocci. D) The Gram-positive cocci may be an obligate anaerobe and was unable to grow in an ambient air incubator. E) All of the choices are possible explanations. - Answers All of the choices are possible explanations What is the first piece of information that is used in the identification of an unknown bacterial isolate? - Answers The Gram stain morphology An ELISA test to detect antibodies to the Rubella virus would include/use all of the following EXCEPT ________. - Answers There are no exceptions here. Each of these items would be used. Which biosafety level(s) requires showering before exit? - Answers 4 The immune system normally discriminates between ________ antigens. - Answers self and non-self T cells attack ________. A) host cells that have been parasitized by microorganisms B) transplanted tissue cells from one host to another C) cancer cells D) All of the choices are correct. - Answers All of the choices are correct The humoral immune response defends against ________. A) bacteria B) bacterial toxins C) viruses D) All of the choices are correct. - Answers All of the choices are correct T cells produce and secrete factors that do not directly interact with invading microorganisms but that augment the body's defense mechanisms. These molecules are called ________. - Answers Cytokines An immune complex resulting from an interaction of antibody with cells or particles that becomes large enough to settle out of solution is called a(n) ________. - Answers precipitation reaction Adaptive immunity refers to the type of specific immunity that ________. A) develops after exposure to antigen B) can result from transfer of antibodies from one individual to another C) can be induced by natural or artificial means D) All of the choices are correct. - Answers All of the choices are correct. The transfer of antibodies in breast milk is a good example of ________. - Answers naturally acquired passive immunity A vaccination is a good example of ________. - Answers artificially acquired active immunity Botulinum antitoxin produced in a horse and given to a human suffering from botulism food poisoning is an example of ________. - Answers artificially acquired passive immunity When an individual's immune system responds to an appropriate antigenic stimulus during the course of daily activities, this is called ________. - Answers naturally acquired active immunity Class I and II MHC molecules ________. - Answers consists of a complex of two protein chains The major histocompatibility complex directs the production of proteins called ________. - Answers both class I and class II Class II major histocompatibility complex molecules are found on all of the following types of cells EXCEPT ________. - Answers red blood cells Class I major histocompatibility complex molecules are found on ________ cells. - Answers all nucleated Cytotoxic T lymphocytes are distinguished from other lymphocytes by the presence of ________. - Answers CD8 If a T cell that has received signal 1 for activation fails to also receive signal 2 it may become ________. - Answers Anergic