Bacteriology 303- Exam 2- Summer 03

Bacteriology 303- Exam 2- Summer 03 - ‘i 4'BacteriolOgy...

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Unformatted text preview: ‘i 4 'BacteriolOgy 303 . f/“i/X . * Second Examination {/f" r553, JUly 18, 2003 6 ' .‘2 Instructions: \ / 63"”: . \ f» Use a No. 2 pencil. Write your name and student Lil/number above on the front page Of the examination. On ' the answer sheet print your name and identification number in the boxes indicated and blacken the ' corresponding circles below. In answering the examination questions, blacken one of the five letter circles for each‘ of the questions. You may write on the examination but do not make stray marks on the answer sheet. ' Turn in both the examination (question booklet) and the answer sheet at the end of the test period. ' Questions 1-4. 'The following data are used to plot the growth of Bacillus megaterium over a 2-day period of time. The bacteria were inoculated intofresh medium at an original cell density of 1000 cells per ml. Growth was determined by viable cell counts (colony forming units/ ml or cfu/ml) over a period of 48 hours yielding 'the following results: 1000 cfu/ml at 2 hours, LQEfiuLmJALflngs, Migmjmlwatjuhours, 106 cfu/ ml at 12 hours, 99 cfu/ml at 24 hours, 109 cfu/ml at 30 hours, 109 cfu/ml at 40 hours and 109 cfu ml at”4’8”"libur"s. (LogZ;O.3; Log3=0.5; LogS=0.7) /? ' Ki 1. What is the length of the lag phase of the bacterial culture? . or" “i A. 2 hours » , ' ' ' lime . {000 ‘ C. 6 hours I q [We “fives D. 10 hours V. 0’ - q . E. none of the above V ’L- W $.49 it.) 2.1%“! many generations of bacterial cells occurred during the\total period 0; expogential gro‘wth?<(How.manéyO times did the cell population divide?) , y N ling . . is “e? 1 Q4051}; qg - ’ -t - htwatgifib Is. ~ - . - w - 51% a: - lb” . v’ ' m . . 151.96%“ is; . k _. - 3. What is the approximate generation time (+/- 1 minute) of the bactefiial'bulturew [L A. 18, minutes ‘ 7M WEE; 03- 2’4 minutes ' (QQWN‘W‘ £2? C. 36 minutes _ c w" ' unite». 4. Supposing at 12 hours .u u 0 Of 5‘ V yousxrzecmn: Elan)! count to ' o 'B. 106 cfu/mi c. 107 cfu/ml D. 108 cfu/ml I ' ~ :7? E. 109 cfu/ml fl _. . .,—,~ .41 was . 5. 5,000 bacterial cells. Aftera two-hour lag the culture divides” and grows exponeagialbmfimit’miteffi'fihe stationary. phase at 8 pm with a pepulation of 5x108 cells. What is the generation time of the bacterium? fl 4; a; :me“ ‘ $69,, ' alt.“ 14-22%; ‘ €380 6“: E. 48 minutes- 45.x ‘ 1-ng WK}? 6. Bacterial growth in a chemostat (continuoUs culture) relieves the environmental conditions that restrict exponential growth by ' . A. continuously supplying nutrients to the cells for growtlfi B. continuously removing waste substances from the medium/\ C. continuously removing cells from the culture medium 4 D. both B and C " . all of the Nu 7. in microbiology, sterilization is defined as - A. gentle heating of a substance to reduce the total number of-viable organisms present—fate}? B ,illing all vegetative Cells but not necessarily endospores in a defined area limination of all forms of life in a specific area ' . ~ ‘1 . any chemical or physical treatment which kills bacterial pathogens, especially those present in milk?“3 in a substance - E. the time and te/myrature necessary to bring about a decimal (10—fold)reduction in the number: of microbes . 8. Pasteurization of milk uSing heat accomplishes A. complete elimination of all'microorganisms in the milk V . ‘ _ ‘ B. reduction in the total number of organisms ,but no redugtidn/or eliminationof pathogens in the milk C. elimination of pathogens but no elimination or r ction in the number of'nonpathogens in the milk D. killing all potential pathogens in milk except Mycobacterium tuberculosis @eduction inthe total number of microorganisms and elimination of all potential pathogens in the milk / ‘ 9. Heat-sensitive liquids can be sterilized by A. boiling ‘ B. autoclaving ' ©irradiation - D. filtration E. chemical gas 10. The temperature and time necessary to sterilize a . A. 720/30 minutes i. ' ‘ B. 1000/30 minutes masts D. l600/2 hours E. 1800/1 hour substance in the autoclave is \v 77 77,7 77 7 7, 7 7 7 7 777 . _. '1 1 j The pore diameter of membrane filters used in sterilization processes, selected because it is the largest ‘ pore diameter that will exclude passage of all bacterial cells. is ‘ A. 0.22 nanometers lbol , ‘ WQW“ 3’ B. 32;, micrometers it)” 1363-- 33‘ C. 1.0 micrometer - ' D. 10 micrometer _ W 12. Which statement(s) below refers to chemical food preservatives? ' A. They are cidal in their efje’éc. They are not effective against eukaryotes. . hey must be continually present in the food in order to be effective. D. both A an _ v ' E. all of the we 13. As antimicrobial agents, chemicals such as formaldehyde, hypochlorite (chlorox) and phenolic. compounds (e.g. lysol) are used as ' ' A. preservatiVes @disinfectants C. chemotherapeut' gents D. antibjp'tl’cs ’M’ E. none of the above .14. Distinctions between eukaryotic and procaryotic cells that make the latter selective targets for antimicrobial agents include ’ A. differences in 'DNA replication (DNA polymerase) B. differences in transcription (RNA polymerase)? - C. differences in translation 'D. differences in cell wall structure’f ll efthe above ‘ 15. A characteristic of the beta lactam antibiotics includes A. low therapeutic index (indicates a low degree of selective toxicity) B. limited spectrum of activity ? C. chemical-structure containing a tetrapyrrole ring"(v g D. a bacterio'static mode of action”? ‘E. none of the above 16. Chemical modification of the substituent groups of a naturally-produced beta lactam molecule leads to the industrial development of - ‘ emisynthetic beta lactams f B. sulfa drugs‘ - C. tetracycline . D. cephalosporin _ E. beta lactamase enzymes 17. Ethambutol, isoniazid (NH) and para—amino-salicylic acid (PAS), used in the treatment of tuberculosis, are - examples of A ' * , A. antisep ' B. chemothjfiapeutic agents‘T’ E v C. broad-spectrum antibiotics D. narrow spectrum antibiotics E. none of the above 18. The seleCtive toxicity of the sulfa drugs is achieved on this basis. _ . _ A. They specifically inhibit an. enzyme involved in an ear w tep in the synthesis of bacterial murein. 8. They combine with yeast sterols (ergosterol) and ereby disrupt membranes. C. They bind selectively to the bacterial ribosome and block peptide bond formation between amino acids "during the translation process. . . - _ ey block the synthesis of folic acid in bacteria by acting as analogs of bacterial PABA. E. They inhibit the activity of bactefial‘fiNA polymerase reactions. ‘ 19. What is the mechanism of'action of rifam‘ycin as a primary drug 'n the treatment of tuberculosis? A. it specifically inhibits synthesis and assembly of the bacteri ‘ Wall. ' B. It disrupts membranes of Mycobacterium M losis. C. lt blocks mycolic acid synthesis in Mycobactpflfin tuberculosis. . ‘ D. it binds specifically to the DNA gyrase of bacterial DNA polymerase and prevents unwinding of DNA during the replication process. ' v ‘ @lt inhibits the activity of bacterial RNA polymerase. 20. What is mechanism of action of the aminoglycoside, macrolide and tetracycline antibiotics in bacterial cells? ' . ' - i ‘ J ' A. growth factor analogs that interfere with pr ' otic vitamin metabolism - B. disruption of the outer membrane of Gram- ative bacteria ' C. interference witnfifanscription ' ' D. inhibition of cell walLsynthesis interference with translation 21. Electrons removed'from an inorganic substrate by an aerobic lithotrophic bacterium are ‘ I transferred directly to ' ' A. co2 (Mn to CH4. D. photosystem the phoMthetic m§brane @ carrier in the membrane electron transport system 22. Water microbiologists differentiate fecal enteric bacteria (E. call) from non fecal enteric bacteria (e.g. K/ebsiella or Enterobacter) by means of the presence of this metabolic pathway in the non-fecal group. ‘ A. homolactic pathway B. heterolactic pathway .butanediol pathway . ability to ferment lactose E. glucose fermentation that yields gas (C02) the fermentation of glucose and Shige/Ia does not. Metabolically, enzyme in E. coli which is missing in Shigella? ‘ ~ .A.. 1, ehyd'rOQenae ‘ ' ‘u' intdro iaD‘. formate dehydrogenase /2\ E. KDPWIase . 59 Questions 24-28 refer to the following metabolic pathway: The overall reaction for the fermentation of glucose by Lactobacillus acidophi/us is given in the pathway below. Numbers refer to 355 individual enzymaticreactions of the pathway. ,3; The overall reaction, is: ‘ . ‘ C5H1206 —-—-———--———-——>2 C3H503 (lactic acid) + 56 kcal (per mole glucose) 2.4:- The cleavage enzyme in this pathway that identifies it as the Embden—Meyerhof pathvVay is A. phosphoketolase ' ' . . @ fructose 1,6-diphosphate aldolase C. hexose kinase ' D. pyruvate decarboxylase E. lactate dyhydrogenase 6. The'redu'ction reaction that is mediated by NADH is reaction number Uppopm 03014: .27. Substrate-level phosphorylation that leads to the synthesis of ATP occurs at reaction ' . ~ A. 1 B. 5 D. 10 E. two of the above 28. What is the net gain in ATP per mole of glucose obtained during this fermentation? A. 1 o ‘ _ ' E. none of the above, Questions 29-33 refer to the following metabolic pathway for the utilization of glucose by aerobically-respiring Staphylococcus. ' ' . “Erma enema 33:3}: g:- - M The overallreac’tion is; if ”‘ ' C5H1206 + 6 02 ———— -————>6 C02 +,6 H20 + 688 kcal/mole glucose ‘ . L: 3 ' ' ‘ ' 29. How many moles of NADH are produced in a bacterial cell during the oxidation of one mole of glucose? A. 2 ' ' B. 4 I o .noe of the above 30. At which step'shown in the pathway does an oxidation occur that is mediated by a coenzyme other than NAD? A.l 8.5 .c. ; E.8 . 31. At which step shown in 32. What is the net yield in high energy phosphate (= the pathway does a substrate level phosphorylation occur? ATP or GTP) per mole of glucose when this pathway is cou led to an electron trans ort hos. ho lation s stem? - AIZPZ, \ _. P p P. ry Y 36 B. 26 5+ Arr? C. 36 33. If the complete . A-. 26% B. 30% ‘o.4% ' , pigidation of glucose yields 688 kcal/mole, considering the total e rgy made avail the cell (above), what- is the ove'r'a'll“efficiency'of'this,respiration?-~~~ -' -- " ' ‘ ' (Assume ATP—-—-—-—-T>ADP + P; + 8 . ct be calculated from the data given ' HP??? able to M , , .,..._.-..,......_.~. al/ mole) 31:???) ‘3'; 2,96 ‘ apfi... ‘ hf ' ma- 34. Photosynthesis in the Purple Bacteria suCh as Rhodobactgxmvolves'all of the following except A. chlorophyll that‘absorbs light in the range of 800-1000nm B. fixation of C02 by RUBP carboxylase and the Calvin cycle substancesotherjghan H20 as electron donors for reduction of NADP ' C. use of figured-u ' _ E. synthesis b'f'ATP by cyclic p s x hotophosphorylation (Photosyste-m l) '35. in the light reactions of photosystem ll in the Cyanobacteria A. an electron is ejected and transferred to a pigment in photosystem l T1 B. ATP is produced by the mec 002 is produced ’i’ all of the above . none of the above 36. An important role-of carotenoids in all pigments, involves shielding Chlorophyll from he hanisms of electron transport phosphorylation ' photosynthetic bacteria, besides acting as light-harvesting rmful wavelengths of light wuenching" singlet oxygen, thereby preventing harmful photooxidations in cells . transferring electrons in the photosynthetic electron transport system D. providing electrons to photosystem I for reduction of ferredoxin E. all of the above 37. The function of the Calvin Cycle in autotrophs includes , A. regeneration of ribulose bisphoSphate necessary to drive the cycle B. regeneration C02 for autotrophic C02 fixation - A” C. regeneration of NADPH as a source of reductant ‘ ' \Jggflproducggfinmg; intermediates for cell biosynthesis (anabolismfr the above g ' I , «mecmmmyammmm' -" f; . 38. What process is utilized by the Green Bacteria to obtain to A.Calvi le _. y H re TCA cycl C. codh patw D. both B a C E. none of the above obtain carbon for growth. 39. Which reaction below is involved in autotrophic C02 fixation in the methanogens? A A. Acetyl CoA;-— —-——->Pyruvate r , _ l'B. Succinyl -CoA-——---—-—>alphaMoglutarate C. alpha Ketoglutarate——-——-—->lsocitrate _ .,HDaRibulose-"bisph‘osphate*“¥“€0TWmmmwGZMaRaGlyeeratewmm . E. co + CH3-B1z —--———-——> Acetyl-B12 + qu Wetyhfiofii‘”; ‘ Questions 40-42 refer to the regulation of the following modelofiabiosynthetic pathway: ‘ «0“ .-/' ,r x N“ y . v 2' . K?) x_______> z++—> AA1 'c . >D}\ 40. When the pathway is regulated by feedback inh inhibitedby the presence of an excess A. a . B. d andvx D. 2 - E. x, y and z > C _ ' e f E-———-——f> F V V lbition, the activity of which enzyme(s) is specifically of amino acid 1 (AA1)? 41. When the pathway is regulated by end product repression, the synthesis of which enzyme(s) is repressed in the presence of an excess of amino acid 1 (AA1)? ' ' ‘A. a, b and c . . ‘ 42. The effector molecule that. binds to the regulatory site of enzyme d is . -., s. _.. ._ sppteg garment».- lactgéetcfinnotibgwgleaw fdgéfi‘nterfiglfifloiys‘idsfl E. none of the above ' 44. In the positive control Of transcription of_ the lac operon (e.g. catabolite'repression) cyclic AMP is re ired for A. activgg'p ’e lac repressor B. inactigatififi the lac repressor ' ctivating the CAP protein D. inactivating the’CAP protein E. two of the above 45. In a repressible operon (e.g. the trp operon), in the presence of the effector (signal)-molecule, the repressorIRES;Egiflmigrélumnwwflu‘u:mxfi“may”Shmmiwmlmazlmmuv~ ' n.“ . .. ., n: ...... .. .. igfi’a‘ét’i‘vfiland can bind to t 'ope tor site-W} . "*B:'“a‘ctT\7E“a“nd-ca'nnot"bifitl’td"tfiE‘d‘fiE‘FWtsifié' C. inactive and ‘cannot bind to the operator ’site 9mm "‘ Questions 46-50 refer to the plot below which illustrates growth (as optical density) of E3cherichia coii in the following minimal medium: KH2P04 - 2.09 K2HPO4 7.09 M9804 ' 0.2 g (NH4)2$O4 ' 1.0 9 glucose 1.0 g lactose 5.0 9 tap water 1 liter 46. The pattern of growth illustrated is ‘ QDEXQQ [_Vbacterial growth curve i““‘-'.'f‘B. diauxic growt. . Continuous culture _ D. synchronous growth E. biennial growth 47.'During what period of growth is the . 0- hou s ' C. 8-10 hours , D. 10-20 hours E. 20-28 hours 1 o 1 2 Time (hours) 16 20 24 28 referred to as generation time of the culture the fastest? ‘ l .48. At what time during? the grewth curve are the _cells utilizing glucose as a source of carbon and energy? A. 0—4 hou —-B. 4-8 hours We: D. 10-20 hours E. none of the above 49. At what time does cyclic AMP begin» _A. 2 hours B. I ours D. 10 hours E. 20 hours 50. At what time is growth initiated usin A. 0 hours B. 4 hours C. 8J1Q rs @iw—u E. 20 hours to accumulate in the cells? 9 lactose as a soUrce of carbon and energy? 10 Dm._..:_>_0 m<\S 2m;— wIL. me<O_QZ_ X OOIJJGJO<£DmmOD Umm30> $280 66me wszn—wwm Pony—moo .m> zwwOIQ "—0 0,2ij DMN_._<DD_>_DZ_ ‘ N3 ufihmEouwso «£3882: 8km =5 .comfims. 5 82:2,; 28 g 88m E a 32. 303.3 :o_um:_m>m Ucm mcswwh yo SEC 2:. meOQmmm MAQEHBE < mmF<OEZ_ « om av wv Du wv mv Eu mv NV Eu ov MEX , SE. 8.09. “900w 2889“. E:E_xw_>_ . . H: “5an Hwm30> m m m. m D O D m. D D D m. 0 m 0 m D O m. m m. D m < m m m_ 0 m 0 D m. 0 m. m < m 0 m mm mm mm on mm «.0 mm Nm 5 on mm mm RN mm mm .VN mm mm FN ON mv m: t‘ m: 3 3.. Mr Nv : or m x-NO’JV'OQDNOO Hmxrmx. "Em: oon “whoow .90... 50% mmufiwma "we". 88 .K 33. ...
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Bacteriology 303- Exam 2- Summer 03 - ‘i 4'BacteriolOgy...

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