Andrea alban Exam 3 -2 - microbiology PDF

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General Microbiology - SCB 260 Fall I 2020 Exam # 3 Please highlight your answers in yellow

Name: Andrea Alban .

1) Which of the following methods is used to preserve food by slowing down the metabolic processes of foodborne microbes? A. lyophilization B. nonionizing radiation C. freezing D. heat E. pasteurization 2) Select the mismatched pair. A. sterilant — inhibits the growth of all living microorganisms B. virucide — inactivates viruses C. fungicide — kills yeasts and molds D. germicide — kills microbes 3) Ethylene oxide A. is a good antibiotic B. is sporicidal C. require high heat to be effective D. is used for food preservation E. is a sterilizing agent for heat-sensitive materials 4) Which of the following pairs is mismatched? A. Ionizing radiation – hydroxyl radicals B. Ozone – takes electrons from substances C. Plasma sterilization – free radicals D. Supercritical fluids – CO2 E. Ultraviolet radiation – desiccation 5) Which of the following is a limitation of the autoclave? A. It requires an excessively long time to achieve sterilization. B. It cannot inactivate viruses. C. It cannot be used with heat-labile materials. D. It cannot kill endospores. E. It cannot be used with glassware. 6) Which of the following disinfectants acts by disrupting the plasma membrane? A. soaps B. aldehydes C. plasma gas D. bisphenols E. heavy metals 7) Which of the following antibiotics does NOT interfere with cell wall synthesis? A. cephalosporins B. gentamicin C. natural penicillins D. monobactam E. vancomycin

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8) Which concentration of ethanol is the most effective bactericide? A. 100 percent B. 70 percent C. 40 percent D. 30 percent E. 20 percent 9) All of the following are methods of food preservation EXCEPT A. microwaves B. organic acids. C. desiccation D. osmotic pressure. 10) Bone and tendons for transplant are decontaminated by

A. ethylene oxide. B. glutaraldehyde. C. peroxygens. D. plasma sterilization. E. supercritical fluids

11) The antibiotic tetracycline binds to the 30S subunit of the ribosome, as shown by the dark black bar on the right portion of the diagram in the above figure. The effect is to A. prevent attachment of DNA. B. prevent peptide bond formation. C. prevent transcription. D. stop the ribosome from moving along the mRNA. E. interfere with the attachment of the tRNA to mRNA-ribosome complex. 12) Inhibition of protein synthesis in bacteria may be achieved by treatment with A. Polymyxin B, Rifampin and Trimethoprim, Sulfonamide B. Chloramphenicol, Erythromycin, Quinolones, Cephalosporins C. Erythromycin, Streptomycin, Tetracycline, Chloramphenicol D. Penicillins, Bacitracin, Vancomycin, Tetracycline E. Trimethoprim, Cephalosporins, Streptomycin, Chloramphenicol 13) More than half of our antibiotics are A. produced by fungi. B. produced by bacteria. C. synthesized in laboratories. D. produced by Fleming. E. produced by eukaryotic organisms.

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14) Which of the antimicrobial drugs below has the broadest spectrum of activity? A. streptomycin B. acyclovir C. penicillin G D. isoniazid E. tetracycline Table 1 The following results were obtained from a disk-diffusion test for microbial susceptibility to antibiotics. Staphylococcus aureus was the test organism. Antibiotic

Zone of Inhibition

A

3 mm

B

17 mm

C

0 mm

D

10 mm

15) In Table 1, the most effective antibiotic tested was A. A B. B C. C D. D E. The answer cannot be determined based on the information provided. 16) In the presence of penicillin, a cell dies because A. it lacks a cell wall. B. cell wall weakens and lysing occurs C. it lacks a cell membrane. D. competitive inhibition occurs E. protein synthesis is inhibited 17) Transient microbiota differ from normal microbiota in that transient microbiota A. cause diseases. B. are found in a certain location on the host. C. are acquired by direct contact. D. are present for a relatively short time. E. Are present for a longtime in the host 18) In mutualism, A. both organisms benefit B. one organism benefit, and the other is unaffected C. both organisms are unaffected D. one organism benefit at the expenses of the other 19) Which of the following definitions is INCORRECT? A. endemic: a disease that is constantly present in a population B. epidemic: a disease that is endemic across the world C. pandemic: a disease that affects a large number of people in the world in a short time D. sporadic: a disease that affects a population occasionally E. incidence: number of new cases of a disease 20) Symptoms of disease differ from signs of disease in that symptoms: 3

A. are specific for a particular disease. B. are changes observed by the physician. C. are changes felt by the patient. D. always occur as part of a syndrome. 21) Which of the following definitions is INCORRECT? A. acute: a short-lasting primary infection B. inapparent: infection characteristic of a carrier state C. chronic: a disease that develops slowly and lasts for months D. primary infection: an initial illness E. secondary infection: a long-lasting illness 22) Koch observed Bacillus anthracis multiplying in the blood of cattle. What is the condition specifically called when bacteria are multiplying (growing) in the blood? A. bacteremia B. focal infection C. local infection D. septicemia E. systemic infection 23) The major significance of Robert Koch's work is that A. microorganisms are present in a diseased animal. B. diseases can be transmitted from one animal to another. C. microorganisms can be cultured. D. microorganisms cause disease. E. microorganisms are the result of disease. 24) The spread of disease agents via contaminated water is an example of _____ transmission. A. vehicle B. direct contact C. mechanical D. biological E. All of the above 25) Emergence of infectious diseases can be attributed to A. antibiotic resistance. B. climatic changes. C. new strains of previously known agents. D. ease of travel. E. The emergence of infectious diseases can be attributed to all of the above 26) Which of the following involves collecting all data that describe the occurrence of the disease under study? A. descriptive epidemiology B. analytical epidemiology C. CDC epidemiology D. experimental epidemiology E. case reporting 27) If a prodromal period exists for a certain disease, it should occur prior to A. illness B. decline C. convalescence D. incubation

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28) Which of the following pairs is mismatched? A. malaria – foodborne transmission B. salmonellosis – vehicle transmission C. syphilis – direct contact D. influenza – droplet infection 29) What type of organism produces saxitoxin? A. helminth B. alga C. fungus D. Protozoan E. None of the above 30) Which of the following is/are predisposing factor(s) of disease? A. lifestyle B. genetic background C. climate D. occupation E. All of the above are predisposing factors of disease. 31) Healthcare-associated infections were also called ________ infections. A. nosocomial B. opportunistic C. chronic D. emerging 32) In the pyrogenic response Gram-negative endotoxins cause the following events. What is the second step? A. Body temperature is reset in the hypothalamus. B. Fever occurs. C. IL-1 is released. D. LPS (endotoxins) are released from gram-negative bacteria. E. Phagocytes ingest gram-negative bacteria. 33) Proteins secreted by pathogens that bind iron are known as A. superantigen B. siderophores C. leukocidins D. hemolysins

34) The ID50 is A. a measure of pathogenicity. B. the dose that will cause an infection in 50 percent of the test population. C. the dose that will cause an infection in some of the test population. D. the dose that will kill 50 percent of the test population.

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35) Bacteria such as E. coli and Salmonella produce invasins that bind host cells, thus causing the cells to A. release TNF. B. produce iron-binding proteins. C. engulf the bacteria by membrane ruffling. D. destroy the bacteria. E. release cytokines. 36) Superantigens produce intense immune responses by stimulating lymphocytes to produce A. endotoxins. B. exotoxins. C. cytokines. D. leukocidins. E. interferons. 37) Which of the following is NOT a membrane-disrupting toxin? A. A-B toxin B. hemolysin C.. leukocidin D. streptolysin O

38) What is the action of bacterial kinases? A. to coagulate fibrinogen B. to hydrolyze hyaluronic acid C. to breakdown collagen D. to break down IgA antibodies E. to break down fibrin 39) In 1849, who showed that most people infected with cholera in London drank from the Board Street pump? A. Florence Nightingale B. John Snow C. Robert Koch D. Ignaz Semmelweis 40) Which of the following is NOT a cytopathic effect of viruses? A. antigenic change on the host cell surface B. host cells fusing to form multinucleated syncytia C. inclusion bodies forming in the cytoplasm or nucleus D. gain of contact inhibition 41) All of the following are used by bacteria to adhere to host cell surface EXCEPT A. M protein. B. adhesins/ligands. C. fimbriae. D. glycocalyx E. A-B toxins. 42) In A-B exotoxins, which component binds to the host cell receptor in the first step so that the exotoxin can enter the cell. A. A B. B 6

C. A and B at the same time D. not unknown 43) Which one of the following is NOT a way fungi cause disease? A. by antigen variation B. by producing toxins C. by secreting proteases D. by provoking an allergic response 44) What is the most common type of nosocomial infection? A. lower respiratory infection B. surgical infection C. bacteremia D. urinary tract infection E. custaneous infection 45) Disease not transmitted from host to host is called A. nosocomial B. noncommunicable C. contagious D. communicable 46) Niclosamide prevents ATP generation in mitochondria. You would expect this drug to be effective against A. gram-negative bacteria. B. gram-positive bacteria. C. helminths. D. Mycobacterium tuberculosis. E. viruses. 47) An example of a noncommunicable disease is A. measles B. chicken pox C. tetanus D. influenza 48) Normal microbiota can benefit the host by preventing the overgrowth of harmful microorganisms. This is called microbial A. antagonism B. symbiosis C. mutualism D. commensalism 49) All of the following substances are used to preserve foods EXCEPT A. biguanides B. sulfur dioxide C. potassium sorbate D. sodium nitrite E. calcium propionate. 50) Which of the following contributes to the virulence of a pathogen? A. numbers of microorganisms that gain access to a host 7

B. evasion of host defenses C. toxin production D. numbers of microorganisms that gain access to a host and evasion of host defenses E. numbers of microorganisms that gain access to a host, evasion of host defenses, and toxin production

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