General Microbiology - Exam 1 Solutions | BSCI 223, Exams of Microbiology

Download General Microbiology - Exam 1 Solutions | BSCI 223 and more Exams Microbiology in PDF only on Docsity! BSCf223 Fall20AS Stewart Exam #1 Your Name: /'19 1* Dr. Stewort Exom 1 October 11, 2005 IMPORTANT THINGS TO DO BEFORE YOU GET STARTED: 1. Please make sure that your copy of the exam has 11 pages (including this page). Did you check? L/- 2. Write your name and your TA's first name here AND on the top of page2 (worth 1 point!!). B*T2?3 Genersl Microbiology YourName: Your TA's name or your Lab Section: 3. Please read and sign the UMCP Honor Pledge below. I pfefge on m1 frorwr tfiat I fiaue rct givm or received any urnutfwizef assktutce ofl tfiis e4aninatiorL Your signature below ufatSggr your agreement to abide by this pledge page 1 BSCI223 Fall2005 Stewart Exam #l Your Name: wt?tw/#k/t//MfrM/*t%/g*?trM.i-,tl ?enerol Instructions: Answer directly on your test poges. Usepen. Usepen! Answer multipte choice guestions on the fine provided next to the guestion number. Q0.[1 pt] What is your TA's first name? Write it here: Q1-12. Finish labeling the cell components diagram below. Shown below is a partially labeled diagram depicting the major structural/functional features of a Gram-negative bacterium. In the spaces provided, write the correct labels for the major structural features of this cell. For each structure (label) indicate one major function and one major biochernical comoonent (DNA, RNA, protein, carbohydrate, peptidoglycan, or phospholipid) in the spaces provided immediately the the right. I provided answers for some of the components as an example and to help orient you within the diagram. [12 pts: I pt. for each answer] o phospholipid _ ) seleclive permeobility borien Y r DNA o cqrries cell's genetic info. I I I I O'lit+".rt' -Z+-+E*+-'s#*-^ '- t, A complefe answer willhave somefhing written on each of the horizontal lines on this diagran. No exfra credit for wrifing in extra informafion, so don'f wasfe fine doirg if: move on!! 13. [1pt.] Using a double-headed arrow ( diagram. $ ), indicate the location of the periplasmic space on the 6ytoplosrnic membrane -0 page2 BSC|223 Fall2005 Stewart Exam #1 Your Name: rJL,.rttL&t 7;tu.r/-tJt)>7/r,).,/tirt,/--.rt.2u)urx:r'"'r/)r"'i;:/"+7/r"4'iiatr: Use the choices listed below to answer questions 35-39. I pt each] A choice may be used once, more than once, or not at all. (a) the cytoplasmic membrane of an Archaeal cell (b) the cell wall of an Archaeal cell (c) the inner membrane of a Gram-negative bacterium (d) the outer membrane of a Gram-negative bacterium (e) the cytoplasmic membrane of a Gram-positive bacterium (D the cell wall of a Gram-positive bacterium D35. Where are porins most likely to be found? /. I tz L ZA. Where is a membrane composed of a phospholipid monola),er most likely to be found? rtl Where are teichoic acids most likely to be found? IJ I D:S. Which is most likely to contain hydrocarbon chains linked to glycerol molecules via ether linkages? f- lg. Which structure is most likely to contain N-acetyl glucosamine; N-acetyhnuranic acid, and tetra-peptides connected by peptide interbridges? 40.[ pt] Polyrnixins are agroup of antibiotics that disrupt some bacterial membranes by binding preferentially to Lipid A molecules. Forthis reason, polymixins are expected to: a. be more effective in killing Gram-positive bacteria than in killing Gram-negative bacteria b. be more effective in killing archaea than in killing Gra:n-negative bacteria ..O U" more effective in killing Gram-negative bacteriathan in killing Grarn-positive bacteria d. be more effective in killing yeast than in killing bacteria e. induce sporulation in Gram-negative bacteria 41.[1 pt] Lysozyn,e has antimicrobial activity because it: a. is a Blactam antibiotic b. inhibits cell wall transpeptidases c. cleavespeptidoglycancrosslinks t L9 cleaves the glycan (NAG-NAM) chains of peptidoglycan e. inhibits 70S ribosomes /L page 5 Below is a list of terms that relate to classification of antimicrobial drugs. Use these terms to answer questions 42 and 43. Any term may be used once, more than once, or not at all. BSC|223 Fatl 2005 Stewart Exam #1 Your Name: (a) broad spectrum (c) bactericidal (e) natural antibiotic (g) inhibits binding of IRNA to 70S ribosomes t ' / 1,., r, ) t .. ,i rr j " ; 44. [2 p*] Penicillin and Doxycycline are both said used to refer to antir,ricrobial drugs? I ; ..ilt{./_/L,, ,t 1,.,j ,l !aI >. 1 t, >)' rtrj i'f.? t r"., r^ u / t -, *x j - (b) narrow spectrum (d) bacteriostatic (f) semi-synthetic antimicrobial (h) iniribits cell wall transpeptidase t" , ( i L^rlri 1,, .."\-. '-.* ( to have 'selective toxicitv'. What does this tenn mean rvhen r ,'zr,, ../'. -'.|'.' i-.#+|i.&i-j*, t"t"t-.,,r /t--,t'/ L., \ 42. 14 pts.l Penicillin G is isolated directly from cultures of Penicilliunt chrysogeru,tnt. It is effective agamst many Gram-positive bacteri4 but against few Gram-negatives. From lecture and your reading you know its mechanism of action and target in cells. Choose 4 terms from the list above (a-h) that apply to Penicillin G: ;^1,- ic,1 llt. , * ,u ,rr I ' '. i - 43. [4 pts.] To rnake Doxycycline, Tetracycline is first isolated from cultures of Streptot tyces rhnosus, arrd then the chemical structure of the Tetracycline is modified slightly in the laboratory to generate Doxycycline. This drug is effective against most Gram-positive and Gram-negative bacteria. From lecture and your reading you should know its mechanism of action and target in cells. Choose 4 terms from the list above (a-h) that apply to Doxycycline: (,.,., .,-,,rl.l'' ('i" t i ,\. 45. [2 pts] ^,JltrtP- 't Y 46. [2 pts] Penicillin kills rnany Gram-positive bacteri4 but those that produce the enzyme B-lactamase can continue growing in the presence of penicillin. Briefly explain how B-lactamase confers this Bacterial cells that produce S-lactamase are resistant to penicillins; does this mean that they will also be resistant to Tetracycline? Why or why not? "Lr'- !-- ,\ 47 . 12 pial ln the chemotaxis system of E. coli, receptor proteins 'senss'the cell's chemical environment and communicate this information to the flagellar motors. Which of the following statements best describes how this communication occurs? The receptor proteins and the flagella both bind to actin and stimulate its polymerization. The receptors directly contact the flagella and cause thern to either retract or extend, depending on whether the cell needs to move forward or backrvard. The receptors generate a transmernbrane proton gradient to alter the speed of flagellar rotation. The receptors control the rate of ATP production which, in tum, detennines the speed of flagellar rotation. The receptors communicate with a protein kinase (CheA) that, in fum, cornmunicates with another protein, CheY, and CheY flren interacts with the flagella to modulate its rotational direction. -l a. &D d. ,\\ \J a page 6 BSC!223 Fall2005 Stewaft Exam #1 Your Name: 48. Matching (Each answer may be used only once) ll pt. eachl :\ / ) gaseous alkylating agent often used to sterilize bulky objects in hospitals C- antiseptic effective as a70o/o aqueous solution; damages membranes and'coagulates proteins' Tt.z- phenolic derivative often used as antiseptic; commonly found rn toothpastes, deodorant soaps, lotions I i general term that refers to a chemical used to reduce the nunbers of microorganisms on living tissue ,1 'general term that refers to a chemical used to reduce the nunber of microbes present on inanimate objects 1/.r'1/.,.,JLat /r)r/,)/2-1.1j-4rr/*1,:+i'.r-)-9rrJ.,-/--'.'--1,,r-'-'.':/'.?/'rJ-'*2-r-,. /,ttr,,-,. ,^z'disinfectant / ethylene oxide . fl. antiseptic 9j'triclosan 49. [1 pt.] Which one the following microbiologists devised a set of steps that can be follorved to prove that a particular microbe causes a specific infectious disease? a. Pasteur b. Leeuwenhoek o" Winogradsky . d.l Koch\-/e. rlemmrns 50. I pt.] Which of the following features would be most useful for detennining the phylogenetic relationship of two microorganisms? a. ribosome sizes (e.g., 70S or 80S) ofthe microorganisms b. genome size of the microorganisms c. cell shapes of the microorganisms O. nucleotide sequences of genes encoding ribosomal RNA in the microorganisrns e. growth rates of the microorganisms at different temperatures 40 page 7 BSC|223 Fall 2005 Stewart Exam #1 ,vt4*!//)rg/v/*r'*&lr'ltw-u8$hbraffi$lr Your Name: t-,:tbra<'?/jr*bn'/&//}2?-)rJr))ir)//rr-,-'J ^^'-.-../-//."r/,lr'a'*l,azt-4'-9:r7j"-.r" The diagram above shows growth of a batch culture of Bacillus subtilis with the different growth phases labeled as 1-5 62. tI ptl During which phase would you observe the cells maximizing their production of secondary metabolites? a. I b.2 rs/ 3 d.4 e.5 63.I pt.] Bacillus subtilis can fonn endospores. You would begin to observe production of endospores during the transition between which two phases? a. l'--+2 O 2-+3 c. 3--+4 d. 4--+5 64.[2ps.l WhatstimulioreventsusuallyinitiatetheprocessofsporulationinBacillus,Clostridiurn,andother sporulatingbacteria? t-<.'t( - r .iti <.r, L^ .y/-...-.- t-.,.,.t--'"<'r J 65.I pt.] B .subtilis endospores are resistantto: a. temperatures high enough to kill vegetative B. subtilis cells b. radiation doses sufficient to kill vegetative B. subtilis cells c. dessication conditions that would kill vegetative B. subtilis cells d. chemicals that would kill vegetative B. subtilis cells r,$. all ofthe above 66.I pt.] rl The oldest endospores that have been successfully revived 3. 5 days old b. 5 years old c. 500 years old E) zsumillion vears old Y uhundred billion, trillion, gazillion years old. (gemrinated) in a laboratory setting were: -l page 10 BSC!223 Fall2005 Stewart Exam #1 Your Name: )-t.n??'/s'r>)1t ">?r>:+'//ir)iL*a'" )Jj> ,r ,..i.,rr,,rri?&';,?',r> : -:a t'*i.\ r j- a'r.'. Exom 1 Finol Qtrestion [lpoints] This some question will oppear on Exom 1. Youn aruwers will need to fit into the spoce provided. Your work at DuPunt, Inc. continues with the microbe ETPUM, but you have been shifted to the Division of Disposable Diapers. The chemical engineers have devised two different super-absorbent poll,mers [poly-c- ketoglutarate (PK) and poly-fumarate (PF)1. Both polymers have done wonderfully in their "field tests" (be thankful that you don't have that job!). But the engineers would like to ensure that these polymers are biodegradable, and they have asked for your advice on which polymer (poly-o-ketoglutarate or poly-fumarate) would be better to use. Both polymers have molecular weights in excess of 500,000 Daltons. The engineers would like to be able to be able to add ETPUM to a landfill full of Dupont Disposable Diapers, and let the microbes break down the absorbent polymer (by using it as a carbon and energy source), converting it into organic molecules. Your recent work with ETPUM has indicated that it: o secretes a PK/PF depolymerase that can digest both poly-c-ketoglutarate (generating o-ketoglutarate ) and poly-fu marate (generating fumarate) o has a PMF-powered transporter that can transport either a-ketoglutarate or fumarate across the cytoplasmic membrane into the cytoplasm (at a cost of l4 protons per molecule of a-ketoglutarate or fumarate transported) o has all of the enzymes required for glycolysis and the TCA cycle r has, in its cytoplasmic ntentbrane, an ATP synthase and an Electron Transport Chain that makes use of oxygen as the terminal electron acceptor (assume that these rvork just as those of E. coli\. Answer the specific qttestions (2-6) Iisted below; then come baclc and answer the o,-erall Lluestion (#1): 1. Which would be better to use in the diapers? Poly-c-ketoglutarate or poly-fumarate? 1r pt1 ,)r{r t,,,/'-- /- J/r tc,'-t 2. Describe how carbon atoms might find their way from poly-a-ketoglutarate or poly-fumarate into the cytoplasm of ETPUM by answering these questions: a. Why is it important that flre ETPUM PK/PF depolymerase is secreted? 1r pt1 . - - '-. ' J:.- t .J.r/+' .-r., k), r-,., ., . {,- -,-. 1 |.. /t, ;- r:.r/a.,, r. - r- i- r-.,r ./,} i:' b. How would the digestion products generated by PIVPF depolymerase find their ivay into tlie ETPUMcI'toplasrn?[lpr] I),r.r.r. ll..'u,. ,1.;-'o.- ], 'r. ,.. ,:i -.1.,,",, 3. Consider ATP expenditure: Getting the fumarate or c-ketoglutarate into the cytoplasm r.vould require expenditure of PMF, but we can also think of this as ATP expenditure (14 protons used for transport is 14 protons not available for driving ATP production). What ATP-cost results from transport of one molecule of fuilarate or o-ketoglutarate ? 1r pq 'r /t , / I 4. Consider ATP production (don't subtract out the ATP used for transport yet): a. Into what central metabolic pathu'ay of ETPUM can fumarate and a-ketoglutarate i .,rf ! i /'t enter? tt prl b. If ETPUM catabolizes fumarate, how much ATP can it generate? 1r pt.1 -- A, r, ' .\ I, c. If ETPUM catabolizes o-ketoglutarate , how much ATP can it generate?tr pt.l 'l ,J' ' [- 5. Consider net ATP yield (now subtract the ATP used from the ATP produced) a. Can ETPUM grow on poly-fun'rarate as its sole carbon and energy source? 1z prs.1 -z b. Can ETPUM grow on poly-o-ketoglutarate as its sole carbon and energy source? Iz pt l l--; Pa(e tl For 5a and 5b suy "yes" or "no" and give the net ATP yields per moleuile offuntarate and o.- l;etoglutarate