acs biochemistry exam questions
with a+ graded answers
Henderson-Hasselbach gvEquation gv- gvANSWERS-pH gv= gvpKa gv+ gvlog gv([A-] gv/ gv[HA])
FMOC gvChemical gvSynthesis gv- gvANSWERS-Used gvin gvsynthesis gvof gva gvgrowing
gvamino gvacid gvchain gvto gva gvpolystyrene gvbead. gvFMOC gvis gvused gvas gva gvprotecting
gvgroup gvon gvthe gvN-terminus.
Salting gvOut gv(Purification) gv- gvANSWERS-Changes gvsoluble gvprotein gvto gvsolid
gvprecipitate. gvProtein gvprecipitates gvwhen gvthe gvcharges gvon gvthe gvprotein gvmatch gvthe
gvcharges gvin gvthe gvsolution.
Size-Exclusion gvChromatography gv- gvANSWERS-Separates gvsample gvbased gvon
gvsize gvwith gvsmaller gvmolecules gveluting gvlater.
Ion-Exchange gvChromatography gv- gvANSWERS-Separates gvsample gvbased gvon
gvcharge. gvCM gvattracts gv+, gvDEAE gvattracts gv-. gvMay gvhave gvrepulsion gveffect gvon gvlike
gvcharges. gvSalt gvor gvacid gvused gvto gvremove gvstuck gvproteins.
Hydrophobic/Reverse gvPhase gvChromatography gv- gvANSWERS-Beads gvare gvcoated
gvwith gva gvcarbon gvchain. gvHydrophobic gvproteins gvstick gvbetter. gvElute gvwith gvnon-H-
bonding gvsolvent gv(acetonitrile).
Affinity gvChromatography gv- gvANSWERS-Attach gva gvligand gvthat gvbinds gva gvprotein gvto
gva gvbead. gvElute gvwith gvharsh gvchemicals gvor gvsimilar gvligand.
SDS-PAGE gv- gvANSWERS-Uses gvSDS. gvGel gvis gvmade gvfrom gvcross-linked
gvpolyacrylamide. gvSeparates gvbased gvoff gvof gvmass gvwith gvsmaller gvmolecules
gvmoving gvfaster. gvVisualized gvwith gvCoomassie gvblue.
SDS gv- gvANSWERS-Sodium gvdodecyl gvsulfate. gvUnfolds gvproteins gvand gvgives gvthem
gvuniform gvnegative gvcharge.
Isoelectric gvFocusing gv- gvANSWERS-Variation gvof gvgel gvelectrophoresis gvwhere
gvprotein gvcharge gvmatters. gvInvolves gvelectrodes gvand gvpH gvgradient. gvProtein gvstops
gvat gvtheir gvpI gvwhen gvneutral.
FDNB gv(1-fluoro-2,3-dinitrobenzene) gv- gvANSWERS-FDNB gvreacts gvwith gvthe gvN-
terminus gvof gvthe gvprotein gvto gvproduce gva gv2,4-dinitrophenol gvderivative gvthat gvlabels
gvthe gvfirst gvresidue. gvCan gvrepeat gvhydrolysis gvto gvdetermine gvsequential gvamino
gvacids.
DTT gv(dithiothreitol) gv- gvANSWERS-Reduces gvdisulfide gvbonds.
,Iodoacetate gv- gvANSWERS-Adds gvcarboxymethyl gvgroup gvon gvfree gv-SH gvgroups.
gvBlocks gvdisulfide gvbonding.
Homologs gv- gvANSWERS-Shares gv25% gvidentity gvwith gvanother gvgene
Orthologs gv- gvANSWERS-Similar gvgenes gvin gvdifferent gvorganisms
Paralogs gv- gvANSWERS-Similar gv"paired" gvgenes gvin gvthe gvsame gvorganism
Ramachandran gvPlot gv- gvANSWERS-Shows gvfavorable gvphi-psi gvangle
gvcombinations. gv3 gvmain gv"wells" gvfor gvα-helices, gvß-sheets, gvand gvleft-handed gvα-
helices.
Glycine gvRamachandran gvPlot gv- gvANSWERS-Glycine gvcan gvadopt gvmore gvangles.
gv(H's gvfor gvR-group).
Proline gvRamachandran gvPlot gv- gvANSWERS-Proline gvadopts gvfewer gvangles. gvAmino
gvgroup gvis gvincorporated gvinto gva gvring.
α-helices gv- gvANSWERS-Ala gvis gvcommon, gvGly gv& gvPro gvare gvnot gvvery gvcommon.
gvSide-chain gvinteractions gvevery gv3 gvor gv4 gvresidues. gvTurns gvonce gvevery gv3.6
gvresidues. gvDistance gvbetween gvbackbones gvis gv5.4Å.
Helix gvDipole gv- gvANSWERS-Formed gvfrom gvadded gvdipole gvmoments gvof gvall
gvhydrogen gvbonds gvin gvan gvα-helix. gvN-terminus gvis gvδ+ gvand gvC-terminus gvis gvδ-.
ß-sheet gv- gvANSWERS-Either gvparallel gvor gvanti-parallel. gvOften gvtwisted gvto gvincrease
gvstrength.
Anti-parallel gvß-sheet gv- gvANSWERS-Alternating gvsheet gvdirections gv(C gv& gvN-termini
gvdon't gvline-up). gvHas gvstraight gvH-bonds.
Parallel gvß-sheet gv- gvANSWERS-Same gvsheet gvdirections gv(C gv& gvN-termini gvline gvup).
gvHas gvangled gvH-bonds.
ß-turns gv- gvANSWERS-Tight gvu-turns gvwith gvspecific gvphi-psi gvangles. gvMust gvhave
gvgly gvat gvposition gv3. gvProline gvmay gvalso gvbe gvat gvß-turn gvbecause gvit gvcan gvhave gva
gvcis-omega gvangle.
Loops gv- gvANSWERS-Not gvhighly gvstructured. gvNot gvnecessary gvhighly gvflexible, gvbut
gvcan gvoccasionally gvmove. gvVery gvvariable gvin gvsequence.
Circular gvDichroism gv- gvANSWERS-Uses gvUV gvlight gvto gvmeasure gv2° gvstructure. gvCan
gvbe gvused gvto gvmeasure gvdestabilization.
Disulfide-bonds gv- gvANSWERS-Bonds gvbetween gvtwo gv-SH gvgroups gvthat gvform
gvbetween gv2° gvand gv3° gvstructure.
ß-mercaptoethanol gv- gvANSWERS-Breaks gvdisulfide gvbonds.
, α-keratin gv- gvANSWERS-formed gvfrom gv2 gvα-helices gvtwisted gvaround gveach gvother.
gv"Coiled gvcoil". gvCross-linked gvby gvdisulfide gvbonds.
Collagen gv- gvANSWERS-Repeating gvsequence gvof gvGly-X-Pro. gv3 gvstranded gv"coiled
gvcoil". gvContains gvgly gvcore.
Myoglobin gv4° gvStructure gv- gvANSWERS-Symmetric gvhomodimer,
Hemoglobin gv4° gvStructure gv- gvANSWERS-Tetramer. gvDimer gvof gvdimers. gvα2ß2
gvtetramer.
α/ß gvProtein gvFolding gv- gvANSWERS-Less gvdistinct gvareas gvof gvα gvand gvß gvfolding.
α+ß gvProtein gvFolding gv- gvANSWERS-Two gvdistinct gvareas gvof gvα gvand gvß gvfolding.
Mechanism gvof gvDenaturants gv- gvANSWERS-Highly gvsoluble, gvH-binding gvmolecules.
gvStabilize gvprotein gvbackbone gvin gvwater. gvAllows gvdenatured gvstate gvto gvbe
gvstabilized.
Temperature gvDenaturation gvof gvProtein gv- gvANSWERS-Midpoint gvof gvreaction gvis
gvTm.
Cooperative gvProtein gvFolding gv- gvANSWERS-Folding gvtransition gvis gvsharp. gvMore
gvreversible.
Folding gvFunnel gv- gvANSWERS-Shows gv3D gvversion gvof gv2D gvenergy gvstates. gvLowest
gvenergy gvis gvstable gvprotein. gvRough gvfunnel gvis gvless gvcooperative.
Protein-Protein gvInterfaces gv- gvANSWERS-"Core" gvand gv"fringe" gvof gvthe gvinterfaces.
gvCore gvis gvmore gvhydrophobic gvand gvis gvon gvthe gvinside gvwhen gvinterfaced. gvFringe gvis
gvmore gvhydrophilic.
π-π gvRing gvStacking gv- gvANSWERS-Weird gvinteraction gvwhere gvaromatic gvrings
gvstack gvon gveach gvother gvin gvpositive gvinteraction.
σ-hole gv- gvANSWERS-Methyl gvgroup gvhas gvarea gvof gvdiminished gvelectron gvdensity gvin
gvcenter; gvattracts gvelectronegative gvgroups
Fe gvBinding gvof gvO2 gv- gvANSWERS-Fe2+ gvbinds gvto gvO2 gvreversible. gvFe3+ gvhas gvan
gvadditional gv+ gvcharge gvand gvbinds gvto gvO2 gvirreversibly. gvFe3+ gvrusts gvin gvO2 gvrich
gvenvironments.
Ka gvfor gvBinding gv- gvANSWERS-Ka gv= gv[PL] gv/ gv[P][L]
ϴ-value gvin gvBinding gv- gvANSWERS-ϴ gv= gv(bound gv/ gvtotal)x100%
ϴ gv= gv[L] gv/ gv([L] gv+ gv1/Ka)
Kd gvfor gvbinding gv- gvANSWERS-Kd gv= gv[L] gvwhen gv50% gvbound gvto gvprotein. gv
Kd gv= gv1/Ka
with a+ graded answers
Henderson-Hasselbach gvEquation gv- gvANSWERS-pH gv= gvpKa gv+ gvlog gv([A-] gv/ gv[HA])
FMOC gvChemical gvSynthesis gv- gvANSWERS-Used gvin gvsynthesis gvof gva gvgrowing
gvamino gvacid gvchain gvto gva gvpolystyrene gvbead. gvFMOC gvis gvused gvas gva gvprotecting
gvgroup gvon gvthe gvN-terminus.
Salting gvOut gv(Purification) gv- gvANSWERS-Changes gvsoluble gvprotein gvto gvsolid
gvprecipitate. gvProtein gvprecipitates gvwhen gvthe gvcharges gvon gvthe gvprotein gvmatch gvthe
gvcharges gvin gvthe gvsolution.
Size-Exclusion gvChromatography gv- gvANSWERS-Separates gvsample gvbased gvon
gvsize gvwith gvsmaller gvmolecules gveluting gvlater.
Ion-Exchange gvChromatography gv- gvANSWERS-Separates gvsample gvbased gvon
gvcharge. gvCM gvattracts gv+, gvDEAE gvattracts gv-. gvMay gvhave gvrepulsion gveffect gvon gvlike
gvcharges. gvSalt gvor gvacid gvused gvto gvremove gvstuck gvproteins.
Hydrophobic/Reverse gvPhase gvChromatography gv- gvANSWERS-Beads gvare gvcoated
gvwith gva gvcarbon gvchain. gvHydrophobic gvproteins gvstick gvbetter. gvElute gvwith gvnon-H-
bonding gvsolvent gv(acetonitrile).
Affinity gvChromatography gv- gvANSWERS-Attach gva gvligand gvthat gvbinds gva gvprotein gvto
gva gvbead. gvElute gvwith gvharsh gvchemicals gvor gvsimilar gvligand.
SDS-PAGE gv- gvANSWERS-Uses gvSDS. gvGel gvis gvmade gvfrom gvcross-linked
gvpolyacrylamide. gvSeparates gvbased gvoff gvof gvmass gvwith gvsmaller gvmolecules
gvmoving gvfaster. gvVisualized gvwith gvCoomassie gvblue.
SDS gv- gvANSWERS-Sodium gvdodecyl gvsulfate. gvUnfolds gvproteins gvand gvgives gvthem
gvuniform gvnegative gvcharge.
Isoelectric gvFocusing gv- gvANSWERS-Variation gvof gvgel gvelectrophoresis gvwhere
gvprotein gvcharge gvmatters. gvInvolves gvelectrodes gvand gvpH gvgradient. gvProtein gvstops
gvat gvtheir gvpI gvwhen gvneutral.
FDNB gv(1-fluoro-2,3-dinitrobenzene) gv- gvANSWERS-FDNB gvreacts gvwith gvthe gvN-
terminus gvof gvthe gvprotein gvto gvproduce gva gv2,4-dinitrophenol gvderivative gvthat gvlabels
gvthe gvfirst gvresidue. gvCan gvrepeat gvhydrolysis gvto gvdetermine gvsequential gvamino
gvacids.
DTT gv(dithiothreitol) gv- gvANSWERS-Reduces gvdisulfide gvbonds.
,Iodoacetate gv- gvANSWERS-Adds gvcarboxymethyl gvgroup gvon gvfree gv-SH gvgroups.
gvBlocks gvdisulfide gvbonding.
Homologs gv- gvANSWERS-Shares gv25% gvidentity gvwith gvanother gvgene
Orthologs gv- gvANSWERS-Similar gvgenes gvin gvdifferent gvorganisms
Paralogs gv- gvANSWERS-Similar gv"paired" gvgenes gvin gvthe gvsame gvorganism
Ramachandran gvPlot gv- gvANSWERS-Shows gvfavorable gvphi-psi gvangle
gvcombinations. gv3 gvmain gv"wells" gvfor gvα-helices, gvß-sheets, gvand gvleft-handed gvα-
helices.
Glycine gvRamachandran gvPlot gv- gvANSWERS-Glycine gvcan gvadopt gvmore gvangles.
gv(H's gvfor gvR-group).
Proline gvRamachandran gvPlot gv- gvANSWERS-Proline gvadopts gvfewer gvangles. gvAmino
gvgroup gvis gvincorporated gvinto gva gvring.
α-helices gv- gvANSWERS-Ala gvis gvcommon, gvGly gv& gvPro gvare gvnot gvvery gvcommon.
gvSide-chain gvinteractions gvevery gv3 gvor gv4 gvresidues. gvTurns gvonce gvevery gv3.6
gvresidues. gvDistance gvbetween gvbackbones gvis gv5.4Å.
Helix gvDipole gv- gvANSWERS-Formed gvfrom gvadded gvdipole gvmoments gvof gvall
gvhydrogen gvbonds gvin gvan gvα-helix. gvN-terminus gvis gvδ+ gvand gvC-terminus gvis gvδ-.
ß-sheet gv- gvANSWERS-Either gvparallel gvor gvanti-parallel. gvOften gvtwisted gvto gvincrease
gvstrength.
Anti-parallel gvß-sheet gv- gvANSWERS-Alternating gvsheet gvdirections gv(C gv& gvN-termini
gvdon't gvline-up). gvHas gvstraight gvH-bonds.
Parallel gvß-sheet gv- gvANSWERS-Same gvsheet gvdirections gv(C gv& gvN-termini gvline gvup).
gvHas gvangled gvH-bonds.
ß-turns gv- gvANSWERS-Tight gvu-turns gvwith gvspecific gvphi-psi gvangles. gvMust gvhave
gvgly gvat gvposition gv3. gvProline gvmay gvalso gvbe gvat gvß-turn gvbecause gvit gvcan gvhave gva
gvcis-omega gvangle.
Loops gv- gvANSWERS-Not gvhighly gvstructured. gvNot gvnecessary gvhighly gvflexible, gvbut
gvcan gvoccasionally gvmove. gvVery gvvariable gvin gvsequence.
Circular gvDichroism gv- gvANSWERS-Uses gvUV gvlight gvto gvmeasure gv2° gvstructure. gvCan
gvbe gvused gvto gvmeasure gvdestabilization.
Disulfide-bonds gv- gvANSWERS-Bonds gvbetween gvtwo gv-SH gvgroups gvthat gvform
gvbetween gv2° gvand gv3° gvstructure.
ß-mercaptoethanol gv- gvANSWERS-Breaks gvdisulfide gvbonds.
, α-keratin gv- gvANSWERS-formed gvfrom gv2 gvα-helices gvtwisted gvaround gveach gvother.
gv"Coiled gvcoil". gvCross-linked gvby gvdisulfide gvbonds.
Collagen gv- gvANSWERS-Repeating gvsequence gvof gvGly-X-Pro. gv3 gvstranded gv"coiled
gvcoil". gvContains gvgly gvcore.
Myoglobin gv4° gvStructure gv- gvANSWERS-Symmetric gvhomodimer,
Hemoglobin gv4° gvStructure gv- gvANSWERS-Tetramer. gvDimer gvof gvdimers. gvα2ß2
gvtetramer.
α/ß gvProtein gvFolding gv- gvANSWERS-Less gvdistinct gvareas gvof gvα gvand gvß gvfolding.
α+ß gvProtein gvFolding gv- gvANSWERS-Two gvdistinct gvareas gvof gvα gvand gvß gvfolding.
Mechanism gvof gvDenaturants gv- gvANSWERS-Highly gvsoluble, gvH-binding gvmolecules.
gvStabilize gvprotein gvbackbone gvin gvwater. gvAllows gvdenatured gvstate gvto gvbe
gvstabilized.
Temperature gvDenaturation gvof gvProtein gv- gvANSWERS-Midpoint gvof gvreaction gvis
gvTm.
Cooperative gvProtein gvFolding gv- gvANSWERS-Folding gvtransition gvis gvsharp. gvMore
gvreversible.
Folding gvFunnel gv- gvANSWERS-Shows gv3D gvversion gvof gv2D gvenergy gvstates. gvLowest
gvenergy gvis gvstable gvprotein. gvRough gvfunnel gvis gvless gvcooperative.
Protein-Protein gvInterfaces gv- gvANSWERS-"Core" gvand gv"fringe" gvof gvthe gvinterfaces.
gvCore gvis gvmore gvhydrophobic gvand gvis gvon gvthe gvinside gvwhen gvinterfaced. gvFringe gvis
gvmore gvhydrophilic.
π-π gvRing gvStacking gv- gvANSWERS-Weird gvinteraction gvwhere gvaromatic gvrings
gvstack gvon gveach gvother gvin gvpositive gvinteraction.
σ-hole gv- gvANSWERS-Methyl gvgroup gvhas gvarea gvof gvdiminished gvelectron gvdensity gvin
gvcenter; gvattracts gvelectronegative gvgroups
Fe gvBinding gvof gvO2 gv- gvANSWERS-Fe2+ gvbinds gvto gvO2 gvreversible. gvFe3+ gvhas gvan
gvadditional gv+ gvcharge gvand gvbinds gvto gvO2 gvirreversibly. gvFe3+ gvrusts gvin gvO2 gvrich
gvenvironments.
Ka gvfor gvBinding gv- gvANSWERS-Ka gv= gv[PL] gv/ gv[P][L]
ϴ-value gvin gvBinding gv- gvANSWERS-ϴ gv= gv(bound gv/ gvtotal)x100%
ϴ gv= gv[L] gv/ gv([L] gv+ gv1/Ka)
Kd gvfor gvbinding gv- gvANSWERS-Kd gv= gv[L] gvwhen gv50% gvbound gvto gvprotein. gv
Kd gv= gv1/Ka
