Micro Final Exam Questions And Answers

Micro Final Exam Questions And
Answers
**Domagkx-xCORRECTxxANSWER-
discoveredxSULFANILAMIDE,x1stxantimicrobialxmassxproducedxtoxpublic

**ForxBeta-lactamxantibiotics,xwhatxisxthexsignificancexofxthexbeta-
lactamxring?xWhatxisxthexmodexofxactionxofxthisxtypexofxantibioticx(howxdoesxitxkillxbacteria)?x
PenicillinxandxMethicillinx(axsemisyntheticxofxpenicillin)xarexexamplesxofxB-
lactamsxthatxhavexthexsamexmodexofxaction.x-xCORRECTxxANSWER--xBeta-
lactamsxbindxtoxenzymesxthatxcross-linkxNAMxsubunitsx(transpeptidase)
-
xKillsxbacteriaxbyxinhibitingxcellxwallxsynthesis,xstopsxpeptidexbondxformationxthereforexwallxi

sxnotxcomplete

**Howxdoxbacteriaxacquirexresistance?x-xCORRECTxxANSWER-
MutationsxofxchromosomalxgenesxandxacquisitionxofxexogenousxDNAxthroughxhorizontalxg
enextransferx(transformation,xtransduction,xconjugation)

**HowxdoesxA.xveroniixpreventxphagocytosisxbyxleechxhemocytes?x-
xCORRECTxxANSWER-

A.xveroniixhasxaxtypex3xsecretionxsystemx(injectosome),xdoesn'txgetxtakenxupxbyxphagocyto
sisxsoxitxcanxsurvivexinxhostxandxestablishxaxsymbioticxrelationship

**Howxdoesxcoagulasexandxantigenicxvariationxaidxinxthexbacterialxinfectionxprocess?x-
xCORRECTxxANSWER-

Coagulasex=xformsxclotxaroundxbacteriaxtoxblockxaccessxtoximmunexsystemxcellsxsoxtheyxd
on'txgetxdegraded

Antigenicxvariationx=xbacteriaxproducexdifferentxantigensxtoxstayxaheadxofximmunexrespons
e

**Howxdoesxstreptokinasexorxstaphylokinasexaidxinxthexinvasionxprocess?x-
xCORRECTxxANSWER-

Dissolvesxclotsxtoxreleasexpathogenxtoxbloodstreamxandxdeeperxtissues

, **Howxdoesxthexsulfonamide,xsulfanilamide,xinhibitxbacterialxgrowth?xHowxisxPABAxinvolve
dxinxfolicxacidxsynthesis?xWhyxisxsulfanilamidex'non-
toxic'xtoxhumans?xWhatxisxaxstructuralxanalog?x-xCORRECTxxANSWER--
xInhibitxmetabolicxpathway,xstopsxfolicxacidxsynthesisxinxbacteriaxandxprotozoa;xsulfanilami

dex=xstructuralxanalogxofxPABAx-->xcompetitivexinhibitor
-xPABAxisxaxprecursorxforxfolicxacidxsynthesis
-xNotxtoxicxbecausexhumansxdon'txhavexsynthesisxpathwayxforxfolicxacid
-
xStructuralxanalogx=xsimilarxtoxsubstratexbecausexitxcanxfitxinxactivexsitexbutxactuallyxdifferen

t

**HowxisxWolbachiaxpassedxfromxgenerationxtoxgeneration?x-xCORRECTxxANSWER-
Transovarianxtransmissionx-xonlyxbyxfemales

**Whatxarex5xresistancexmechanisms?xSpecifically,xwhatxisxbeta-
lactamase?xHowxdoesxmethicillinxresistancexwork?xWhatxisxanxeffluxxpump?x-
xCORRECTxxANSWER-1.xDrugxinactivation

-xBeta-lactamasex=xbreaksxdownxbeta-
lactamxringxinxpenicillin,xnoxlongerxeffectivexbcxnoxringxtoxbindxtoxtranspeptidasextoxstopxpep
tidexbondxformation
2.xAlterxtargetxofxdrugxsoxitxbindsxlessxeffectively
-xMethicillinxresistancex-xlockx&xkeyxanalogy,xnormallyxbeta-
lactamxabxx(key)xfitsxintoxPBPx(lock);xifxorganismxpicksxupxMecxAxgene,xlockxchangedxtoxPB
P2Axandxbeta-lactamxabxxcan'txfitxintoxitxanymore;xresistancexdeveloped
3.xReducexdrugxaccumulation
-xEffluxxpumpsx-xantibioticxgetsxintoxcellxbutxgetsxpumpedxoutxbeforexitxcanxbind
-xDecreasexpermeability
4.xAlterxmetabolicxpathway
5.xBacteriaxinxbiofilmsxcanxresistxantimicrobialsx-xantibioticsxcan'txdiffuse

**Whatxarexprebioticsxandxprobiotics?x-xCORRECTxxANSWER-
Prebioticsx=xhelpxstimulatexgrowth,xspecialxformxofxdietaryxfiber,xactsxasxaxfertilizerxforxgoodx
bacteria

Probioticsx=xaddxtoxgoodxbacteriaxcount,xlivexbacteriaxfoundxinxyogurtx&xotherxfermentedxfo
ods

**Whatxarexsomexbacterialxsurfacexstructuresxwexdiscussedxinxclassxthatxcontributextoxadh
erence?x-xCORRECTxxANSWER-Glycoproteinsxandxlipoproteins

Alsoxfimbriae,xpili,xHemagglutaninx(allxfirmlyxattachedxtoxcellxsurface,xdeterminexhostxcellxs
pecificity)

**Whatxarexthexbig-
picturextakenxhomexmessagesxfromxthexfruitxflyxexperiment?xHowxdidxtheyxshowxthis?x-