Seminar assignments chapter 6 questions and answers PDF

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!MULT I PLE(C HOI C E.((C hoose(the(one(alternative(that(best(completes(the(statement(or(answers(the(question.( Figure!6.1

!1)! In!Figure!6.1,!which!line!best!depicts!a!facultative!anaerobe!in!the!absence!of!O 2?! 1)! _______!A)! a! B)! b! C)! c!!2)! In!Figure!6.1,!which!line!best!illustrates!a!mesophile!at!5°C!above!its!optimum!temperature?! 2)! _______!A)! a! B)! b! C)! c!!3)! In!Figure!6.1!,which!line!best!depicts!an!obligate!anaerobe!in!the!presence!of!O 2?! 3)! _______!A)! a! B)! b! C)! c!!4)! In!Figure!6.1,!which!line!best!depicts!a!mesophile!with!an!optimum!temperature!of!!incubated!at!! 4)! _______!A)! a! B)! b! C)! c!!5)! In!Figure!6.1,!which!line!shows!the!growth!of!an!obligate!aerobe!incubated!anaerobically?! 5)! _______!A)! a! B)! b! C)! c!!6)! In!Figure!6.1,!which!line!best!illustrates!the!growth!of!a!facultative!anaerobe!incubated!aerobically?! 6)! _______!A)! a! B)! b! C)! c!!7)! In!Figure!6.1,!which!line!best!depicts!a!catalase-negative!cell!incubated!aerobically?!

7)! _______!A)! a! B)! b! C)! c!!8)! M icrococci!are!facultative!halophiles.!In!Figure!6.1,!which!line!best!depicts!the!growth!of!M icrococcus(luteus!in!a!nutrient! medium!containing!7.5%!NaCl?! 8)! _______!A)! a! B)! b! C)! c!!9)! In!Figure!6.1,!which!line!best!depicts!a!psychrophile!incubated!at!room!temperature?! 9)! _______!A)! a! B)! b! C)! c!!10)! In!Figure!6.1,!which!line!best!depicts!a!psychrotroph!incubated!at!0°C?! 10)! ______!A)! a! B)! b! C)! c!!11)! In!Figure!6.1,!which!line!best!depicts!Neisseria(gonorrhoeae!when!growing!inside!the!human!body?! 11)! ______!A)! a! B)! b! C)! c!!12)! T he!addition!of!which!of!the!following!to!a!culture!medium!will!neutralize!acids?! 12)! ______!A)! Carbon!B)! Buffers!C)! pH!D)! Sugars!E)! Heat!!13)! Salts!and!sugars!work!to!preserve!foods!by!creating!a! 13)! ______!A)! Depletion!of!nutrients.!B)! Hypotonic!environment.!C)! Lower!pH.!D)!

Hypertonic!environment.!E)! Lower!osmotic!pressure.!!14)! T he!term!facultative(anaerobe!refers!to!an!organism!that! 14)! ______!A)! R equires!less!oxygen!than!is!present!in!air.!B)! Prefers!to!grow!without!oxygen.!C)! Uses!oxygen!or!grows!without!oxygen.!D)! Is!killed!by!oxygen.!E)! Doesn'฀t!use!oxygen!but!tolerates!it.!!15)! Which!of!the!following!is!an!advantage!of!the!standard!plate!count?! 15)! ______!A)! Determines!the!number!of!viable!cells!B)! Cannot!be!used!to!count!bacteria!in!food!C)! R equires!incubation!time!D)! Chemical!and!physical!requirements!are!determined!by!media!and!incubation.!E)! Can!readily!count!cells!that!form!aggregates!!16)! Which!of!the!following!is!an!advantage!of!the!direct!microscopic!count?! 16)! ______!A)! R equires!a!large!number!of!cells!B)! Enumerates!dead!cells!C)! R equires!no!incubation!time!D)! Can!readily!count!organisms!that!are!motile!E)! Sample!volume!is!unknown.!!17)! Which!of!the!following!is!NOT !used!to!determine!metabolic!activity?! 17)! ______!A)! NO 2-!produced!from!the!electron!transport!chain!B)! Decreased!dissolved!oxygen!C)! Acid!production!from!fermentation!D)! CO 2!produced!from!the!Krebs!cycle!E)! Turbidity!!18)! T hirty-six!colonies!grew!in!nutrient!agar!from!1.0!ml!of!undiluted!sample!in!a!standard!plate!count.!How!many!cells!were! in!the!original!sample?! 18)! ______!A)! 4! B)! 36! C)! 18! D)! 9! E)! 72!!Figure!6.2

!19)! In!Figure!6.2,!which!section!shows!a!growth!phase!where!the!number!of!cells!dying!equals!the!number!of!cells!dividing?! 19)! ______!A)! a!B)!

b!C)! c!D)! d!E)! a!and!c!!20)! In!Figure!6.2,!which!sections!of!the!graph!illustrate!a!logarithmic!change!in!cell!numbers?! 20)! ______!A)! c!and!d!B)! a!and!b!C)! b!and!d!D)! a!and!c!E)! b!only!!21)! M ost!bacteria!grow!best!at!pH! 21)! ______!A)! 7.! B)! 1.! C)! 14.! D)! 9.! E)! 5.!!Figure!6.3

!22)! Figure!6.3!shows!three!containers!of!water!connected!by!tubes.!A!selectively!permeable!membrane!divides!each!tube.! Solutes!are!added!to!each!container!to!give!final!concentrations!of!5%!NaCl!in!(a);!10%!NaCl!in!(b);!and!5%!sucrose!in!(c).! When!the!experiment!is!first!set!up,!the!initial!movement!of!water!will!be! 22)! ______!A)! a!to!c;!b!to!c;!c!to!a.!B)! a!to!b;!b!to!c;!c!to!a.!C)! a!to!b;!c!to!b;!c!to!a.!D)! a!to!c;!c!to!b;!c!to!a.!E)! b!to!a;!b!to!c;!c!to!a.!!23)! A!culture!medium!on!which!only!gram-positive!organisms!grow!and!a!yellow!halo!surrounds!Staphylococcus(aureus! colonies!is!called!a(n)! 23)! ______!A)! Selective!medium.!B)! Differential!medium.!C)! Enrichment!culture.!D)! A!and!B!E)! B!and!C!!24)! A!culture!medium!consisting!of!agar,!human!blood,!and!beef!heart!is!a! 24)! ______!A)! Selective!medium.!B)! R educing!medium.!C)! Differential!medium.!D)! Complex!medium.!E)! Chemically!defined!medium.!!25)!

Which!of!the!following!pairs!is!mismatched?! 25)! ______!A)! M esophile!!!growth!at!25°C!B)! Psychrotroph!!!growth!at!0°C!C)! T hermophile!!!growth!at!37°C!D)! Hyperthermophiles!!!growth!at!100°C!E)! Psychrophile!!!growth!at!15°C!!26)! During!which!growth!phase!will!gram-positive!bacteria!be!most!susceptible!to!penicillin?! 26)! ______!A)! Death!phase!B)! Lag!phase!C)! Log!phase!D)! Stationary!phase!E)! T he!culture!is!equally!susceptible!during!all!phases.!!27)! Which!of!the!following!is!the!best!definition!of!generation(time?! 27)! ______!A)! T he!duration!of!log!phase!B)! T he!length!of!time!needed!for!a!cell!to!divide!C)! T he!length!of!time!needed!for!lag!phase!D)! T he!minimum!rate!of!doubling!E)! T he!time!needed!for!nuclear!division!!28)! Which!of!the!following!is!NOT !a!direct!method!to!measure!microbial!growth?! 28)! ______!A)! Standard!plate!count!B)! M PN!C)! Direct!microscopic!count!D)! M etabolic!activity!E)! Filtration!!29)! Which!group!of!microorganisms!is!most!likely!to!spoil!a!freshwater!trout!preserved!with!salt?! 29)! ______!A)! Psychrophiles!B)! Anaerobes!C)! Facultative!halophiles!D)! Hyperthermophiles!E)! T hermophiles!!30)! Which!of!the!following!is!an!organic!growth!factor?! 30)! ______!A)! NH 4H 2PO 4!B)! H 2O!C)! NAD + D)! G lucose!E)! Peptone!!31)! Which!of!the!following!is!an!example!of!a!metabolic!activity!that!could!be!used!to!measure!microbial!growth?! 31)! ______!A)! Turbidity!B)! M PN!C)! G lucose!consumption!D)!

Standard!plate!count!E)! Direct!microscopic!count!!32)! An!experiment!began!with!4!cells!and!ended!with!128!cells.!How!many!generations!did!the!cells!go!through?! 32)! ______!A)! 4! B)! 32! C)! 64! D)! 5! E)! 6!!33)! T hree!cells!with!generation!times!of!30!minutes!are!inoculated!into!a!culture!medium.!How!many!cells!are!there!after!5! hours?! 33)! ______!A)! 16!B)! 3!×!210!C)! 1024!D)! 243!E)! 48!!Figure!6.4

!34)! In!Figure!6.4,!in!which!tube!are!microaerophiles!growing?! 34)! ______!A)! a! B)! b! C)! c! D)! d! E)! e!!35)! In!Figure!6.4,!in!which!tube!are!facultative!anaerobes!growing?! 35)! ______!A)! a! B)! b! C)! c! D)! d! E)! e!!36)! In!one!hospital,!Pseudomonas!aeruginosa!serotype!10!infected!the!biliary!tract!of!10%!of!1300!patients!who!underwent! gastrointestinal!endoscopic!procedures.!After!each!use,!endoscopes!were!washed!with!an!automatic!reprocessor!that! flushed!detergent!and!glutaraldehyde!through!the!endoscopes,!followed!by!a!tap!water!rinse.!P.(aeruginosa!10!was!not! isolated!from!the!detergent,!glutaraldehyde,!or!tap!water.!What!was!the!source!of!the!infections?!!

36)! ______!A)! A!biofilm!in!the!reprocessor!!B)! Fecal!contamination!of!the!bile!ducts!!C)! Contaminated!disinfectant!!D)! Bacterial!cell!walls!in!the!water!!!Table!6.1 T hree!different!culture!media!are!shown!below. M edium!A Na2HPO 4

M edium!B

M edium!C

T ide!detergent Na2HPO 4

G lucose

KH 2PO 4 M gSO 4

KH 2PO 4

Peptone (NH 4)2SO 4

CaCl2

M gSO 4

KH 2PO 2

NaHCO 3

(NH 4)2SO 4

Na2HPO 4

37)! In!Table!6.1,!which!medium!(media)!is!(are)!chemically!defined?! 37)! ______!A)! A!B)! B!C)! C!D)! A!and!C!E)! A!and!B!!38)! In!Table,!6.1,!in!which!medium!would!an!autotroph!grow?! 38)! ______!A)! A!B)! B!C)! C!D)! A!and!C!E)! A!and!B!!39)! Assume!you!inoculated!100!cells!into!100!ml!of!nutrient!broth.!You!then!inoculated!100!cells!of!the!same!species!into!200! ml!of!nutrient!broth.!After!incubation!for!24!hours,!you!should!have! 39)! ______!A)! M ore!cells!in!the!200!ml.!B)! M ore!cells!in!the!100!ml.!C)! T he!same!number!of!cells!in!both.!!40)! T he!source!of!nutrients!in!nutrient!agar!is! 40)! ______!A)! Peptone!and!NaCl.!B)! Nutrient.!C)! Peptone!and!beef!extract.!D)! Agar.!E)! All!of!the!above.!!41)! Which!enzyme!catalyzes!the!reaction:!!O 2-!+!O 2-!+!2H +!→!H 2O 2!+!O 2?! 41)! ______!A)! Superoxide!dismutase! B)! Catalase!C)! Oxidase!

D)! Peroxidase!!42)! Which!enzyme!catalyzes!the!reaction:!!2H 2O 2!→!2H 2O!+!O 2?! 42)! ______!A)! Oxidase! B)! Superoxide!dismutase!C)! Catalase! D)! Peroxidase!!43)! Which!enzyme!catalyzes!the!reaction:!!H 2O 2!+!2H +!→!2H 2O?! 43)! ______!A)! Oxidase! B)! Catalase!C)! Peroxidase! D)! Superoxide!dismutase!!Table!6.2 T he!following!data!show!growth!of!two!bacteria!on!different!media.

!44)! T he!data!in!Table!6.2!indicate!that!S.(aureus!is!a(n)! 44)! ______!A)! Aerobe.!B)! Facultative!halophile.!C)! Facultative!anaerobe.!D)! Halophile.!E)! M esophile.!!45)! Patients!with!indwelling!catheters!are!susceptible!to!infections!because! 45)! ______!A)! Bacteria!cause!infections.!B)! T heir!immune!systems!are!weakened.!C)! Biofilms!develop!on!catheters.!D)! Infections!can!be!transmihed!from!other!people.!E)! Injected!solutions!are!contaminated.!!ESSAY.((Write(your(answer(in(the(space(provided(or(on(a(separate(sheet(of(paper.( Figure!6.5

!46)! In!each!graph!in!Figure!6.5,!the!culture!was!incubated!at!30°C!in!glucose!minimal!salts!broth,!aerobically.!T he!bacterium! is!a!facultative!anaerobe!with!an!optimum!temperature!of!37°C!and!can!metabolize!glucose!and!lactose.!Indicate!how! each!growth!curve!would!change!under!the!conditions!indicated!in!each!graph.!Draw!the!new!graphs,!or!write!"฀no! change."฀!!47)! A!patient!with!a!heart!pacemaker!received!antibiotic!therapy!for!streptococcal!bacteremia!(bacteria!in!the!blood).!One! month!later,!he!was!treated!for!recurrence!of!the!bacteremia.!When!he!returned!6!weeks!later,!again!with!bacteremia,!the! physician!recommended!replacing!the!pacemaker.!Why!did!this!cure!his!condition?!!Table!6.3 Bacterial!generation!times!were!calculated!in!the!media!shown!below. All!media!were!prepared!with!tap!water!and!incubated!aerobically!in!the!light.

!48)! Compare!and!contrast!the!growth!requirements!of!the!bacteria!listed!in!Table!6.3.!Which!of!the!media,!if!any,!are! chemically!defined?!

!1)! B!2)! B!3)! C!4)! B!5)! C!6)! A!7)! C!8)! B!9)! C!10)! B!11)! A!12)! B!13)! D!14)! C!15)! A!16)! C!17)! E!18)! B!19)! C!20)! C!21)! A!22)! C!23)! D!24)! D!25)! C!26)! C!27)! B!28)! D!29)! C!30)! C!31)! C!32)! D!33)! B!34)! E!35)! B!36)! A!37)! A!38)! A!39)! C!40)! C!41)! A!42)! C!43)! C!44)! B!45)! C!46)! !47)! !48)!...