Biochem 50q.doc

8/10/2019 Biochem 50q.doc

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USMLE WORLD STEP 1 BIOCHEMISTRY

Question List

Biochemistry Q No: 1 Endocrinology Biochemistry Q No: 43 Hepatobiliary system

Biochemistry Q No: 2 Neurology Biochemistry Q No: 44 Neurology


Biochemistry Q No: 4 Endocrinology Biochemistry Q No: 46 Endocrinology

Biochemistry Q No: 5 Endocrinology Biochemistry Q No: 47 Gastrointestinal system

Biochemistry Q No: 6 Hepatobiliary system Biochemistry Q No: 48 Endocrinology

Biochemistry Q No: 7 Hematology Biochemistry Q No: 49 Endocrinology

Biochemistry Q No: 8 Endocrinology Biochemistry Q No: 50 Hematology

Biochemistry Q No: 9 Hepatobiliary system Biochemistry Q No: 51 Pulmonology

Biochemistry Q No: 10 Hepatobiliary system Biochemistry Q No: 52 Neurology

Biochemistry Q No: 11 Gastrointestinal system Biochemistry Q No: 53 Endocrinology

Biochemistry Q No: 12 Hematology Biochemistry Q No: 54 Hematology

Biochemistry Q No: 13 Dermatology Biochemistry Q No: 55 Hematology

Biochemistry Q No: 14 Dermatology Biochemistry Q No: 56 Neurology

Biochemistry Q No: 15 Dermatology Biochemistry Q No: 57 Hepatobiliary system

Biochemistry Q No: 16 Dermatology Biochemistry Q No: 58 Hepatobiliary system

Biochemistry Q No: 17 Neurology Biochemistry Q No: 59 Head and neck


Biochemistry Q No: 19 Musculoskeletal Biochemistry Q No: 61 Hepatobiliary system

Biochemistry Q No: 20 Hepatobiliary system Biochemistry Q No: 62 Hematology

Biochemistry Q No: 21 Endocrinology Biochemistry Q No: 63 Head and neck

Biochemistry Q No: 22 Gastrointestinal system Biochemistry Q No: 64 Musculoskeletal


Biochemistry Q No: 24 Renal Biochemistry Q No: 66 Blood vessels

Biochemistry Q No: 25 Hematology Biochemistry Q No: 67 Neurology

Biochemistry Q No: 26 Endocrinology Biochemistry Q No: 68 Neurology

Biochemistry Q No: 27 Musculoskeletal Biochemistry Q No: 69 Gastrointestinal system

Biochemistry Q No: 28 Neurology Biochemistry Q No: 70 Musculoskeletal

Biochemistry Q No: 29 Musculoskeletal Biochemistry Q No: 71 Endocrinology


Biochemistry Q No: 31 Neurology Biochemistry Q No: 73 Endocrinology

Biochemistry Q No: 32 Pulmonology Biochemistry Q No: 74 Hematology




Biochemistry Q No: 36 Hematology Biochemistry Q No: 78 Dermatology





Biochemistry Q No: 41 Hematology Biochemistry Q No: 83 Gastrointestinal system

Biochemistry Q No: 42 Oncology Biochemistry Q No: 84 Hematology

Biochemistry Q No: 85 Neurology Biochemistry Q No: 110 Blood vessels

Biochemistry Q No: 86 Neurology Biochemistry Q No: 111 Hematology

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Biochemistry Q No: 87 Pulmonology Biochemistry Q No: 112 Head and neck


Biochemistry Q No: 89 Neurology Biochemistry Q No: 114 Musculoskeletal


Biochemistry Q No: 91 Neurology Biochemistry Q No: 116 Gastrointestinal system


Biochemistry Q No: 93 Hematology Biochemistry Q No: 118 Endocrinology

Biochemistry Q No: 94 Hepatobiliary system Biochemistry Q No: 119 Gastrointestinal system

Biochemistry Q No: 95 Neurology Biochemistry Q No: 120 Gastrointestinal system


Biochemistry Q No: 97 Musculoskeletal Biochemistry Q No: 122 Hematology

Biochemistry Q No: 98 Cardiology Biochemistry Q No: 123 Hepatobiliary system


Biochemistry Q No: 100 Cardiology Biochemistry Q No: 125 Gastrointestinal system

Biochemistry Q No: 101 Hematology Biochemistry Q No: 126 Dermatology

Biochemistry Q No: 102 Oncology Biochemistry Q No: 127 Oncology

Biochemistry Q No: 103 Musculoskeletal Biochemistry Q No: 128 Dermatology

Biochemistry Q No: 104 Neurology Biochemistry Q No: 129 Endocrinology


Biochemistry Q No: 106 Endocrinology Biochemistry Q No: 131 Neurology


Biochemistry Q No: 108 Neurology Biochemistry Q No: 133 Hepatobiliary system


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A. GlucokinaseB. Pos!o"#uc$okinaseC. Al%olaseD. Pu'a$e kinaseE. Enolase(. Pu'a$e ca#)o*&laseG. Lac$a$e %e&%#o+enase

Explanation:Glucose is $e ,a-o# s$i,ulan$ o" insulin sec#e$ion. A"$e# +lucose en$e#s $e )e$acells i$ is ,e$a)oli/e% )& +l&col&sis "ollo0e% )& ci$#ic aci% c&cle 0ic #esul$s in $e

+ene#a$ion o" ATP ,olecules. A i+ ATP $o ADP #a$ios 0i$in $e )e$a cells #esul$s in$e closu#e o" !o$assiu, 2ATP3 cannel 0ic causes insulin sec#e$ion )& o!enin+$e 'ol$a+e4 %e!en%en$ calciu, cannel.In $e )e$a cell o" $e !anc#eas $e "i#s$ en/&,e in $e +l&col&$ic !a$0a& is+lucokinase ins$ea% o" e*okinase $e "i#s$ en/&,e o" o$e# $issues. Glucokinasecon'e#$s +lucose $o +lucose 5o!os!a$e. Glucokinase as a ,uc i+e# 2, 16,,ol3 $an e*okinase 6.7 ,,ol3. (u#$e# ,o#e +lucokinase is less sensi$i'e $oallos$e#ic ini)i$ion )& i$s !#o%uc$ +lucose 54!os!a$e. Glucokinase se#'es as a,a-o# +lucose4senso# "o# $e )e$a cell. An inc#ease in se#u, +lucose lea%s $oinc#ease% ,e$a)olis, o" +lucose 0i$in $e )e$a cells ul$i,a$el& lea%in+ $o insulinsec#e$ion )& $e "o#,a$ion o" ATP. Te con'e#sion o" +lucose $o +lucose454 !os!a$e)& +lucokinase is c#ucial an% #a$e li,i$in+. Once ,e$a)oli/e% $o +lucose 54!os!a$e+lucose is #a!i%l& ,e$a)oli/e% in $e +l&col&$ic an% ci$#ic c&cle.Glucokinase %e"ec$s #esul$ in one o" $e $&!es o" ,a$u#i$&4onse$ %ia)e$es.Inac$i'a$in+ ,u$a$ions o" $e +lucokinase +ene lea% $o a %ec#ease in $e en/&,es"unc$ion causin+ %ec#ease in $e ,e$a)olis, o" +lucose lesse# ATP "o#,a$ion an%%i,inise% insulin sec#e$ion.Coices A 4 G3 Te o$e# coices lis$e% a#e en/&,es in'ol'e% in +l&col&$ic !a$0a&s.Dia)e$es ,elli$us is no$ a co,!lica$ion o" %e"ec$s in $ese en/&,es.

E%uca$ional O)-ec$i'e8

Glucokinase is a +lucose senso# 0i$in !anc#ea$ic )e$a cells. Inac$i'a$in+ ,u$a$ionso" $e en/&,e #esul$ in ,il% &!e#+l&ce,ia $a$ can )e e*ace#)a$e% )& !#e+nanc&.

187

Q NO 1:A 9:4&ea#4ol% "e,ale %e'elo!s ,o%e#a$e &!e#+l&ce,ia %u#in+ e# "i#s$!#e+nanc& an% is %ia+nose% 0i$ +es$a$ional %ia)e$es ,elli$us. He# +l&ce,ics$a$us i,!#o'es ,a#ke%l& a"$e# %eli'e#&. Se sa&s $a$ e# ,o$e# an% &oun+e#sis$e# )o$ a% ;i+ )loo% su+a#s< %u#in+ !#e+nanc&. I" $is !a$ien$=s +es$a$ional&!e#+l&ce,ia is +ene$icall& !#e%is!ose% $is !a$ien$ is ,os$ likel& $o a'e%ec#ease% ac$i'i$& in 0ic o" $e "ollo0in+ en/&,es>


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A. Pen&lalanine &%#o*&laseB. Di&%#o)io!$e#in #e%uc$aseC. Do!a,ine &%#o*&laseD. Ho,o+en$isa$e o*i%aseE. ?4,e$&l$#ans"e#ase(. Tosinase

Explanation:De"icienc& o" %i&%#o)io!$e#in #e%uc$ase $e en/&,e #es!onsi)le "o# #e%uc$ion o"%i&%#o)io!$e#in BH@3 $o BH: is $e ,os$ co,,on cause "o# a %e"icienc& o" BH:.Te$#a&%#o)io!$e#in BH:3 is a co"ac$o# "o# en/&,es $a$ !a#$ici!a$e in $e s&n$esiso" $osine DOPAI an% se#o$onin as 0ell as ni$#ic o*i%e. Un%e# no#,al con%i$ions%o!a,ine "#o, $e $u)e#oin"un%i)ula# s&s$e, $&!icall& ini)i$s $e #elease o"!#olac$in. Dec#ease% BH: causes %ec#ease% le'els o" %o!a,ine 0ic $e#e"o#ecause inc#ease% le'els o" !#olac$in.

188

Q NO 2:A ne0)o#n is %ia+nose% 0i$ &!e#!en&lalanine,ia a$ )i#$ an% !lace% ona s!ecial !en&lalanine4#es$#ic$e% %ie$. Se'e#al ,on$s la$e# $e in"an$ as a no#,alse#u, !en&lalanine le'el o0e'e# so,e neu#olo+ical a)no#,ali$ies a#e o)se#'e%.His se#u, !#olac$in le'el is ele'a$e%. Wic o" $e "ollo0in+ en/&,es is ,os$ likel&%e"icien$ in $is !a$ien$>


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Te a)o'e i,a+e illus$#a$es $e )ioce,ical #eac$ion 0e#e)& %o!a,ine iss&n$esi/e% "#o, $osine. Te ini$ial s$e! in $is !a$0a& is $e con'e#sion o"$osine $o DPAI ca$al&/e% )& $e en/&,e $osine &%#o*&lase 0ic uses BH: asa co"ac$o#. Su)seuen$l& DOPA is %eca#)o*&la$ion $o %o!a,ine )& $e en/&,e DOPAca#)o*&lase. Do!a,ine ul$i,a$el& se#'es as $e !#ecu#so# ,olecule $o $eca$ecola,ines e!ine!#ine an% no#e!ine!#ine.Coice A3 Pen&lalanine &%#o*&lase is an en/&,e $a$ con'e#$s in+es$e%!en&lalanine $o $osine. Te a)o'e !a$ien$=s !en&lalanine le'els a'e no#,ali/e%0i$ %ie$ $e#a!& )u$ e as lo0 %o!a,ine le'els. Pa$ien$s 0i$ classic!en&lke$onu#ia o# !en&lalanine &%#o*&lase %e"icienc& %o no$ a'e an& ,e$a)olice##o# 0en !#o%ucin+ %o!a,ine $e#e"o#e $is !a$ien$ ,us$ a'e %i&%#o)io!$e#in#e%uc$ase %e"icienc& 0ice'en 0i$ !en&lalanine #es$#ic$ion causes lo0%o!a,ine le'els see %ia+#a,3.Coice C3 Do!a,ine &%#o*&lase is $e en/&,e $a$ ca$al&/es $e )ios&n$esis o"no#e!ine!#ine "#o, %o!a,ine. I$ %oes no$ use BH: is a co"ac$o#.Coice D3 Alka!$onu#ia is an au$oso,al4#ecessi'e %iso#%e# cause% )& a %e"icienc& o"$e en/&,e o,o+en$isic aci% o*i%ase 0ic no#,all& )#eaks %o0n o,o+en$isic

aci% also calle% alka!$on3 a $o*ic $osine )& !#o%uc$ $a$ is a#,"ul $o )ones an%ca#$ila+e.Coice E3 ?4,e$&l$#ans"e#ase con'e#$s no#e!ine!#ine in$o e!ine!#ine.Coice (3 Al)inis, is cause% )& %e"ec$s in $e )ios&n$esis an% %is$#i)u$ion o",elanin. Melanin is s&n$esi/e% in ,elanoc&$es "#o, $osine )& $e en/&,e$osinase.

E%uca$ional O)-ec$i'e8Te$#a&%#o)io!$e#in BH:3 is a co"ac$o# use% in $e s&n$esis o" $osine %o!ase#o$onin an% ni$#ic o*i%e. Ini$iall& $osine is con'e#$e% $o DOPA )& $e en/&,e$osine &%#o*&lase 0i$ BH: !#esen$ as a co"ac$o#. ?e*$ DOPA is %eca#)o*&la$e%$o %o!a,ine )& $e en/&,e DOPA ca#)o*&lase.

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A. Tia,ineB. Ri)o"la'inC. ?iacinD. Pi%o*ineE. Bio$in(. (olic aci%

Explanation:

Pi%o*ine 'i$a,in B53 is an essen$ial co"ac$o# "o# $e $#ansa,ina$ion an%%eca#)o*&la$ion o" a,ino aci%s "o# +luconeo+enesis an% "o# o$e# essen$ial)ioce,ical !#ocesses. T#ansa,ina$ion #eac$ions $&!icall& occu# )e$0een an a,inoaci% an% an 4ke$o aci%. Te a,ino +#ou! is $#ans"e##e% $o $e a4ke$o aci% "#o, $ea,ino aci% an% $e 4ke$o aci% $e#e)& )eco,es an a,ino aci%.Tus in $is ues$ion o*aloace$a$e a4ke$o aci%3 #eac$s 0i$ +lu$a,a$e a,ino aci%3$o "o#, as!a#$a$e $e #esul$in+ a,ino aci%3 an% 4ke$o+lu$a#a$e $e #esul$in+ a4ke$o aci%3. T#ansa,inases a,ino $#ans"e#ases3 a#e $e en/&,es $a$ ca$al&/e

190

Q NO 3:O*aloace$a$e "o#,s as!a#$a$e 0ile #eac$in+ 0i$ +lu$a,a$e. Wic o" $e"ollo0in+ ,os$ likel& !a#$ici!a$es in $is #eac$ion>


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$#ansa,ina$ion #eac$ions an% !i%o*al !os!a$e 'i$a,in B53 se#'es as anessen$ial co"ac$o# "o# $e $#ansa,inase.Coice A3 Tia,ine 'i$a,in B13 se#'es as a coen/&,e "o# a nu,)e# o" i,!o#$an$en/&,es inclu%in+ $#anske$olase a4ke$o+lu$a#a$e %e&%#o+enase an% !u'a$e%e&%#o+enase.Coice B3 Ri)o"la'in 'i$a,in B@3 is use% in %e&%#o+enase #eac$ions in'ol'in+ (M?an% (AD.Coice C3 Man& %e&%#o+enases use ?AD an% ?ADP 0ic a#e "o#,e% "#o, niacin.?iacin 'i$a,in B9 o# nico$inic aci%3 %e"icienc& is kno0n as !ella+#a an% is classicall&associa$e% 0i$ $e "ou# Ds8 %e#,a$i$is %e,en$ia %ia##ea an% i" un$#ea$e% %ea$.Coice E3 Bio$in is a 0a$e#4solu)le 'i$a,in $a$ is a co"ac$o# "o# all "ou# ca#)o*&laseen/&,es8 !u'a$e ca#)o*&lase ace$&l CoA ca#)o*&lase !#o!ion&l CoA ca#)o*&lasean% 94,e$&lc#o$on&l4CoA4ca#)o*&lase.Coice (3 (olic aci% is an essen$ial co"ac$o# in nucleic aci% s&n$esis an% a%e"icienc& o" ei$e# "ola$e o# 'i$a,in B1@ #esul$s in ,e+alo)las$ic ane,ia.


T#ansa,ina$ion #eac$ions $&!icall& occu# )e$0een an a,ino aci% an% an 4ke$o aci%.Te a,ino +#ou! "#o, $e a,ino aci% is $#ans"e##e% $o $e a4ke$o aci% an% $e a4ke$o aci% in $u#n )eco,es an a,ino aci%. Pi%o*al !os!a$e 'i$a,in B53 se#'esas a co"ac$o# in a,ino aci% $#ansa,ina$ion an% in %eca#)o*&la$ion #eac$ions.

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A. Pos!oli!ase CB. Li!o*&+enaseC. P#o$ein kinase CD. Pos!o%ies$e#aseE. A%en&la$e c&clase

Explanation:Te G4!#o$ein4cou!le%4#ece!$o#s a'e a 'e#& ca#ac$e#is$ic s$#uc$u#e 0i$ se'en$#ans,e,)#ane #e+ions an e*$#acellula# %o,ain an% an in$#acellula# %o,ain cou!le%0i$ $e $#i,e#ic G4!#o$ein. In $ei# inac$i'a$e% s$a$e G4!#o$eins e*is$ ase$e#o$#i,e#s consis$in+ o" al!a )e$a an% +a,,a su)uni$s 0i$ +uanosine%i!os!a$e GDP3 $i+$l& )oun% $o $e al!a su)uni$. G !#o$eins a#e ac$i'a$e% a"$e#)in%in+ o" o#,one $o $e e*$#acellula# %o,ain. Te "i#s$ s$e! in ac$i'a$ion o" a G4!#o$ein occu#s 0en GDP is e*can+e% "o# GTP on $e al!a su)uni$. Once )oun% $oGTP $e al!a su)uni$ %issocia$es "#o, $e )e$a an% +a,,a su)uni$s an% e*!osesi$s ca$al&$ic %o,ain "o# ei$e# a%en&la$e c&clase o# !os!oli!ase C %e!en%in+ on$e li+an%.I" $e S4!#o$ein al!a su)uni$ ac$i'a$es !os!oli!ase C $en $e %e+#a%a$ion o"!os!a$i%&linosi$ol : 74 )is!os!a$e $o inosi$ol 1 : 74$#i!os!a$e IP93 an%

%iac&l+l&ce#ol DAG3 occu#s. Diac&l+l&ce#ol s$i,ula$es !#o$ein kinase C 0ic is#es!onsi)le "o# so,e in$#acellula# e""ec$s. Inosi$ol 1 : 74$#i!os!a$e IP93!#o%uces ,os$ o" $e in$#acellula# e""ec$s o" $is !a$0a& )& inc#easin+ in$#acellula#calciu, an% ele'a$e% in$#acellula# calciu, ac$i'a$es !#o$ein kinase C. I" $e ac$ion o"

192

Q NO 4:An a+en$ $a$ s!eci"icall& )locks $e in$e#ac$ion o" inosi$ol $#i!os!a$e 0i$i$s in$#acellula# #ece!$o# 0oul% ,os$ likel& %ec#ease $e ac$i'i$& o"8


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IP9 0e#e )locke% as %esc#i)e% in $e ues$ion s$e, $en %ec#ease% ac$i'a$ion o"!#o$ein kinase C 0oul% occu# u!on o#,one )in%in+. Coice C3.Coice A3 Te ac$i'i$& o" !os!oli!ase C 0oul% )e uncan+e% i" IP9 0e#e )locke%)ecause !os!oli!ase C e*e#$s i$s e""ec$ )e"o#e IP9 in $e calciu, F!os!a$i%&linosi$ol secon% ,essen+e# s&s$e,.Coice B3 Li!o*&+enase is an en/&,e #es!onsi)le "o# "o#,a$ion o" leuko$#ienes "#o,a#aci%onic aci%. I$ is no$ in'ol'e% in in$#acellula# si+nalin+.Coice D3 Te#,ina$ion o" $e e""ec$s o" o#,ones $a$ ac$ )& cAMP o# cGMP G4!#o$ein secon% ,essen+e# s&s$e,s is ca##ie% ou$ )& $e en/&,e !os!o%ies$e#ase.Pos!o%ies$e#ase as no e""ec$ on $e IP9 secon% ,essen+e# s&s$e,.Coice E3 Ac$i'a$ion o" a%en&la$e c&clase lea%s $o $e "o#,a$ion o" c&clic AMP an%$e su)seuen$ ac$i'a$ion o" !#o$ein kinase A. P#o$ein kinase A ac$i'a$es $e !#o$eins$a$ !#o%uce $e in$#acellula# e""ec$s o" o#,ones.

E%uca$ional O)-ec$i'e8A"$e# a o#,one )in%s a G4!#o$ein cou!le% #ece!$o# $a$ ac$i'a$es !os!oli!ase C$e ini$ial s$e! o" $e IP9 secon% ,essen+e# s&s$e, in'ol'es %e+#a%a$ion o"

,e,)#ane li!i%s in$o %iac&l+l&ce#ol DAG3 an% inosi$ol $#i!os!a$e IP93 )& $a$en/&,e. P#o$ein kinase C is ac$i'a$e% )& DAG as 0ell as calciu, #elease% "#o,sa#co!las,ic #e$iculu, un%e# $e in"luence o" 1P9.

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A. Gl&ce#olB. AlanineC. Galac$oseD. L&sineE. As!a#a+ine(. Se#ine

Explanation:

Pu'a$e %e&%#o+enase PDH3 is an allos$e#ic en/&,e $a$ con'e#$s !u'a$e in$oace$&l4CoA in $e !#esence o" o*&+en i.e. %u#in+ ae#o)ic ,e$a)olis,3. In $ea)sence o" o*&+en o# 0i$ a %e"icienc& o" PDHI !u'a$e is al$e#na$i'el& con'e#$e% $o

lac$a$e )& $e en/&,e lac$a$e %e&%#o+enase. E*cessi'e lac$a$e !#o%uc$ion in $eses$a$es #esul$s in lac$ic aci%osis.PDH %e"icienc& as a 0i%e s!ec$#u, o" !#esen$a$ions. Because ca#)o&%#a$es ,a&a++#a'a$e lac$ic aci%osis a ke$o+enic %ie$ is #eco,,en%e% in $ese !a$ien$s. A,inoaci% ca$a)olis, "ollo0in+ #e,o'al o" $e a,ino +#ou! #esul$s in "o#,a$ion o"in$e#,e%ia$es $a$ a#e ei$e# +luco+enic !#o%ucin+ in$e#,e%ia$es o" $e ci$#ic aci%c&cle o# !u'a$e3 o# ke$o+enic !#o%ucin+ ace$oace$a$e o# i$s !#ecu#so#s3. So,ea,ino aci%s suc as !en&lalanine isoleucine an% $#&!$o!an a#e )o$ +luco+enic as0ell as ke$o+enic. Leucine an% l&sine Coice D3 a#e e*clusi'el& ke$o+enic an% 0oul%no$ lea% $o inc#ease% "o#,a$ion o" lac$ic aci%. L&sine is an essen$ial a,ino aci% $a$is $o$all& ke$o+enic.Coice A3 Gl&ce#ol "o#,s $e )ack)one $o $#i+l&ce#i%es an% in $e "as$in+ s$a$e0en $#i+l&ce#i%es a#e %e+#a%e% "o# ene#+& +l&ce#ol is #elease% $o )e use% in+luconeo+enesis. Gl&ce#ol can a++#a'a$e lac$ic aci%osis in !a$ien$s 0i$ !u'a$e%e&%#o+enase %e"icienc& )ecause i$ can )e con'e#$e% $o %i&%#o*&ace$one!os!a$e 0ic in $u#n can "o#, !u'a$e an% su)seuen$l& lac$a$e.Coices B an% (3 Alanine is a non4essen$ial +luco+enic a,ino aci% $a$ can )e$#ansa,ina$e% $o "o#, !u'a$e. Si,ila#l& se#ine is a non4essen$ial a,ino aci% $a$can )e con'e#$e% $o !u'a$e )& se#ine &%#a$ase.Coice C3 Galac$ose 0en co,)ine% 0i$ +lucose as a %isacca#i%e "o#,s $e ,ilksu+a# lac$ose. Galac$ose is ,e$a)oli/e% in $e +l&col&$ic !a$0a& $us +alac$ose

"ee%in+ 0ill #esul$ in a++#a'a$ion o" lac$ic aci%osis in !a$ien$s 0i$ !u'a$e%e&%#o+enase %e"icienc&.Coice E3 As!a#a+ine is a non4essen$ial +luco+enic a,ino aci% $a$ is ca$a)oli/e%ini$iall& $o as!a#$a$e )& $e en/&,e as!a#a+inase. As!a#$a$e is $#ansa,ina$e% 0i$al!a ke$o+lu$a#a$e $o !#o%uce +lu$a,a$e an% o*aloace$a$e a +luconeo+enicin$e#,e%ia$e an% an in$e#,e%ia$e in $e TCA c&cle.

E%uca$ional O)-ec$i'e8 Pu'a$e %e&%#o+enase %e"icienc& is a %isease 0i$ ,ul$i!le!ossi)le !#esen$a$ions #an+in+ "#o, neona$al %ea$ $o ,il% e!iso%ic s&,!$o,s ina%ul$oo%. B& !#e'en$in+ $e con'e#sion o" !u'a$e $o ace$&l C6A !u'a$e issun$e% $o lac$ic aci% #esul$in+ in lac$ic aci%osis in $ese !a$ien$s. L&sine an% leucinea#e e*clusi'el& ke$o+enic an% 0oul% no$ inc#ease $e )loo% lac$a$e le'el in !a$ien$ssu""e#in+ "#o, !u'a$e %e&%#o+enase %e"icienc&.

194

Q NO 5:An in"an$ su""e#in+ "#o, se'e#e neu#olo+ical s&,!$o,s an% lac$ic aci%osis is%ia+nose% 0i$ !u'a$e %e&%#o+enase co,!le* %e"icienc&. Wen !lace% on as!ecial %ie$ $e !a$ien$ %e,ons$#a$es so,e %ec#ease in $e )loo% lac$a$e le'el.Wic o" $e "ollo0in+ su)s$ances can )e ,os$ sa"el& su!!le,en$e% $o $is !a$ien$>


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A. Pu'a$e ca#)o*&laseB. O#ni$ine $#ansca#)a,o&laseC. T#anske$olaseD. Succina$e %e&%#o+enaseE. 94H&%#o*&494,e$&l+lu$a#&l4CoA l&ase

Bioce,ical !#ocesses "o# cellula# ,e$a)olis, occu# in %is$inc$ loca$ions 0i$in cells.(o# e*a,!le )4o*i%a$ion o" "a$$& aci%s ke$o+enesis $e ci$#ic aci% c&cle !a#$s o" $eu#ea c&cle ca#)a,o&l !os!a$e s&n$e$ase an% o#ni$ine $#ansca#)a,o&lase3 an%!u'a$e ca#)o*&la$ion all occu# e*clusi'el& 0i$ in $e ,i$ocon%#ia. T#anske$olaseis an en/&,e o" $e !en$ose !os!a$e !a$0a& $a$ uses $ia,ine i$a,in B13 asa co"ac$o#. All o" $e #eac$ions o" $e !en$ose !os!a$e !a$0a& occu# in $ec&$o!las, so $e en/&,e $#anske$olase 0oul% #e,ain in $e o,o+ena$e %esc#i)e%

in $e ues$ion s$e, 0ile $e o$e# en/&,es ,en$ione% in $e o$e# ans0e# coices0oul% )e #e,o'e% )ecause $e& all #esi%e 0i$in $e ,i$ocon%#ia.Coice A3 Pu'a$e ca#)o*&lase ca$al&/es $e ini$ial s$e! in +luconeo+enesis )&con'e#$in+ !u'a$e $o o*aloace$a$e. Tis en/&,e #eui#es )io$in as a co"ac$o# an%"unc$ions 0i$in $e ,i$ocon%#ia.Coice B3 O#ni$ine $#ansca#)a,o&lase ca$al&/es $e secon% s$e! o" $e u#ea c&cle0e#e o#ni$ine an% ca#)a,o&l !os!a$e a#e co,)ine% $o "o#, ci$#ulline. Tis#eac$ion occu#s 0i$in $e ,i$ocon%#ia. De"icienc& o" $is en/&,e lea%s $o&!e#a,,one,ia an% ,en$al #e$a#%a$ion.Coice D3 Succina$e %e&%#o+enase is an en/&,e o" $e TCA c&cle $a$ "unc$ions $ocon'e#$ succina$e $o "u,a#a$e. I$ is an inne# ,i$ocon%#ial ,e,)#ane !#o$ein an%"unc$ions as !a#$ o" $e elec$#on $#ans!o#$ cain.Coice E3 94H&%#o*&494,e$&l+lu$a#l4CoA HMG C6A3 l&ase is a ,i$ocon%#ialen/&,e $a$ is #es!onsi)le "o# ke$o+enesis "#o, HMG CoA. HMG CoA #esul$s "#o,$e %e+#a%a$ion o" leucine a s$#ic$l& ke$o+enic a,ino aci% an% also "#o, s&n$esis)& HMG CoA s&n$ase. Tis ,olecule is also an in$e#,e%ia$e in $e "o#,a$ion o"coles$e#ol.

E%uca$ional O)-ec$i'e8Bioce,ical !#ocesses "o# cellula# ,e$a)olis, occu# in %is$inc$ loca$ions 0i$in cells.(o# e*a,!le )4o*i%a$ion o" "a$l& aci%s ke$o+enesis $e ci$#ic aci% c&cle !a#$s o" $e

u#ea c&cle ca#)a,o&l !os!a$e s&n$e$ase 1 an% o#ni$ine $#ansca#)a,o&lase3an% !u'a$e ca#)o*&la$ion all occu# e*clusi'el& 0i$in $e ,i$ocon%#ia. All o" $e#eac$ions o" $e !en$ose !os!a$e !a$0a& occu# in $e c&$o!las,.

195

Q NO 6:A sa,!le o" li'e# !a#enc&,a is o,o+eni/e% an% cen$#i"u+e% $o #e,o'e,e,)#ane co,!onen$s an% o# +an%les lea'in+ onl& $e c&$osol an% $e !#o$eins i$con$ains. Wic o" $e "ollo0in+ en/&,e ac$i'i$ies is ,os$ likel& !#esen$ in $eo,o+ena$e>


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A. 94cain "ol%in+B. In$e#ac$ion 0i$ H)(C. P#o$on #eleaseD. O*&+en unloa%in+E. @94)is!os!o+l&ce#a$e %e!le$ion

Explanation:Sickle cell ane,ia H)S3 is $e ,os$ co,,on ine#i$e% )loo% %iso#%e# in $e Uni$e%S$a$es. In H)S $e non!ola# a,ino aci% 'aline #e!laces $e ca#+e% a,ino aci%

+lu$a,a$e a$ !osi$ion 5 o" $e )e$a cain. Tis #esul$s in al$e#a$ion o" a &%#o!o)ic!a#$ o" $e )e$a cain $a$ "i$s in$o a co,!le,en$a#& si$e on $e al!a cain o"ano$e# e,o+lo)in ,olecule. Te al$e#e% s$#uc$u#e #esul$s in a++#e+a$ion o"e,o+lo)in ,olecules un%e# ano*ic con%i$ions. A"$e# !ol&,e#i/a$ion H)S ini$iall&"o#,s a +el "ollo0e% )& a ,es0o#k o" "i)#ous !ol&,e#s $a$ causes $e #e% )loo%cells $o %is$o#$ in$o an a)no#,al sickle sa!e. Sicklin+ is !#o,o$e% )& con%i$ionsassocia$e% 0i$ lo0 o*&+en le'els inc#ease% aci%i$& o# lo0 )loo% 'olu,e%e&%#a$ion3.O#+ans in 0ic )loo% ,o'es slo0l& e.+. s!leen li'e# ki%ne&3 a#e !#e%is!ose% $olo0e# o*&+en le'els o# aci%i$&. In a%%i$ion o#+ans 0i$ !a#$icula#l& i+ ,e$a)olic%e,an%s e.+ )#ain ,uscles an% !lacen$a3 !#o,o$e sicklin+ )& e*$#ac$in+ ,o#eo*&+en "#o, $e )loo%. Tese con%i$ions ,ake $ese o#+ans susce!$i)le $o in-u#&"#o, sickle cell ane,ia. Sickle% cells a#e no$ "le*i)le enou+ $o !ass $#ou+,ic#o'ascula$u#e. B& i,!e%in+ )loo% "lo0 $#ou+ $ese 'ascula# )e%s $e sickle%cells cause ,ic#oin"a#c$s in $issues an% !ain"ul 'asoocclusi'e c#ises in $e )one.Coice A3 Glo)in cains o" $e e,o+lo)in $e$#a,e# a#e co,!ac$l& "ol%e% 0i$non!ola# &%#o!o)ic #esi%ues in $e in$e#io# an% ca#+e% !ola# #esi%ues on $esu#"ace. Eac cain as se'e#al al!a elical s$#e$ces secon%a#& s$#uc$u#es3 an%)e$a )en%s $e#$ia#& s$#uc$u#e3. Su)s$i$u$ion o" 'aline "o# +lu$a,ic aci% %oes no$#esul$ in si+ni"ican$ can+e in )e$a "ol%in+.Coice B3 Clinical ,ani"es$a$ions o" sickle cell %isease can )e less se'e#e in !a$ien$s

0o also !#o%uce la#+e# a,oun$s o" H)( in a%ul$oo%. Suc !a$ien$s inclu%e so,e!eo!le o" Mi%%le Eas$e#n %escen$. In "e$al li"e an% ea#l& in"anc& H)( is $e!#e%o,inan$ e,o+lo)in in !a$ien$s 0o !#o%uce a4+lo)in. H)( con$ains $0o al!aan% $0o +a,,a +lo)in cains. H)S %oes no$ !ol&,e#i/e 0en H)( is !#esen$ so!a$ien$s 0i$ sickle cell %isease o"$en %o no$ a'e s&,!$o,s un$il $e H)( "#ac$ion%ec#eases a "e0 ,on$s "ollo0in+ %eli'e#&.Coice C3 P#o$ons a#e #elease% "#o, %eo*&e,o+lo)in in $e lun+s 0e#e $e i+!6@ "a'o#s #elease o" CO@ an% )in%in+ o" o*&+en $o e,o+lo)in. H)S %oes no$ sicklein en'i#on,en$s 0i$ i+ o*&+en con$en$.Coice E3 @194DPG )in%s $e $0o )e$a cains )& ionic )on%in+ an% s$a)ili/es $e$au$ T3 %eo*&e,o+lo)in. Tis )in%in+ %ec#eases $e o*&+en a""ini$& o" e,o+lo)inan% "acili$a$es $e #elease o" o*&+en a$ $e $issue le'el. Wi$ %e!le$ion o" @ 9 DPGI$e a""ini$& o" e,o+lo)in "o# o*&+en 0ill inc#ease an% #esul$ in u!$ake o" o*&+en )&

196

Q NO 7:A 4&ea#4ol% !a$ien$ !#esen$s $o &ou# o""ice acco,!anie% )& is !a#en$s. Heas )een os!i$ali/e% ,ul$i!le $i,es "o# !ain"ul e!iso%es in is an%s an% "ee$ o'e#$e las$ se'e#al &ea#s. He as no kno0n ,e%ical !#o)le,s an% $akes no ,e%ica$ionse*ce!$ "o# ace$a,ino!en "o# !ain con$#ol. You sus!ec$ $a$ e as a 'aline "o#+lu$a,ic aci% su)s$i$u$ion a$ !osi$ion 5 o" $e 4+lo)in cain o" $e e,o+lo)in,olecule. Tis !a$ien$=s e,o+lo)in 0oul% ,os$ likel& a++#e+a$e u!on8


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e,o+lo)in. O*&+ena$e% e,o+lo)in S %oes no$ !ol&,e#i/e $us sicklin+ o"e#&$#oc&$es 0ill )e %ec#ease%.E%uca$ional O)-ec$i'e8He,o+lo)in S H)S3 a++#e+a$es in $e %eo*&+ena$e% s$a$e. H)S !ol&,e#s "o#,"i)#ous s$#an%s $a$ #e%uce #e% )loo% cell ,e,)#ane "le*i)ili$& an% !#o,o$e sicklin+.Sicklin+ occu#s un%e# all con%i$ions associa$e% 0i$ ano*ia inclu%in+ lo0 !H an% i+@I94DPG. Tese in"le*i)le e#&$#oc&$es !#e%is!ose $o ,ic#o'ascula# occlusion an%,ic#o in"a#c$ion.

197


14/85


A. AB. BC. CD. DE. E

Explanation:

Mos$ D?A in u,an cells is "oun% 0i$in $e nucleus8 o0e'e# ,i$ocon%#ia a'e$ei# o0n D?A calle% ,i$ocon%#ial D?A ,$D?A3. Hu,an ,$D?A as 9 +enesco%in+ "o# $i#$een !#o$eins $0o "o#,s o" #R?A an% @@ "o#,s o" $R?A. ,$D?A isin'ol'e% in $e !#o%uc$ion o" so,e o" $e !#o$eins in'ol'e% in o*i%a$i'e ,e$a)olic!a$0a&s 0ile nuclea# D?A enco%es "o# ,os$ o" $e !#o$eins ac$uall& "oun% 0i$in,i$ocon%#ia. All ,i$ocon%#ia an% $e#e"o#e all ,$D?A a#e ,a$e#nall& %e#i'e%"#o, $e ooc&$e an% un%e# +oes ,ini,al can+es %u#in+ $#ans"e# "#o, ,o$e# $oo""s!#in+. Tus $e +ene$ic co%e o" ,$D?A is sli+$l& %i""e#en$ "#o, nuclea# D?A.(o# e*a,!le UGA si+ni"ies a s$o! co%on in nuclea# D?A )u$ co%es "o# $#&!$o!an in,$D?A. Te e*is$ence o" ,i$ocon%#ial D?A $a$ is se!a#a$e "#o, nuclea# D?Asu!!o#$s $e $eo#& $a$ euka#&o$ic cells "i#s$ a!!ea#e% e'olu$iona#& 0en a!#oka#&o$ic cell 0as a)so#)e% in$o ano$e# cell 0i$ou$ )ein+ %i+es$e% "o#,in+ as&,)io$ic #ela$ionsi!. Tis $eo#& is kno0n as $e en%os&,)io$ic $eo#&. Because o"$is uniue +ene$ic $#ans"e# o" ,i$ocon%#ial D?A %iseases a#isin+ "#o, ,u$a$ions in,i$ocon%#ial D?A a#e $#ans,i$$e% "#o, $e ,o$e# $o all o" e# o""s!#in+.Coice A3 Te "ol%e% ,e,)#anous s&s$e, i%en$i"ie% e#e as a ;#ou+.< s$i!!le%a!!ea#ance secon%a#& $o $e !#esence o" nu,e#ous #i)oso,es )oun% $o i$s,e,)#anes 0ic a#e in'ol'e% in $e s&n$esis o" !#o$eins %es$ine% "o# e*!o#$ o#

!acka+in+ in$o +#anules o# o#+anelles.Coice B3 Te %a#k #e+ion i%en$i"ie% 0i$in $e nucleus is $e nucleolus $e si$e o"s&n$esis an% asse,)l& o" #i)oso,al co,!onen$s. Re,e,)e# $a$ $e nucleolus isno$ ,e,)#ane )oun%.Coice C3 Te li+$e# ;elec$#on lucen$< #e+ions 0i$in $e nucleus i%en$i"&e$e#oc#o,a$in o# D?A $a$ as )een un !acka+e% an% is ac$i'el& )ein+$#ansc#i)e%.Coice E3 Tis elec$#on %ense ,e,)#ane )oun% s!e#ical s$#uc$u#e #e!#esen$s ane*oc#ine sec#e$o#& +#anule con$ainin+ e*oc#ine en/&,es an% o$e# !#o$eins!acka+e% "o# sec#e$ion.E%uca$ional O)-ec$i'e8Rese,)lin+ !#oka#&o$ic D?A an% )ein+ %e#i'e% co,!le$el& "#o, $e ,o$e#,i$ocon%#ial D?A ,$D?A3 is $e ,os$ co,,on non4nuclea# D?A "oun% ineuka#&o$ic cells.

198

Q NO 8:S,all ci#cula# ,olecules o" D?A a#e isola$e% "#o, e*oc#ine !anc#ea$ic cells.Tese ,olecules #ese,)le )ac$e#ial D?A an% co%e "o# !#o$eins $#ans"e# R?A an%#i)oso,al R?A. Te ,olecules a'e )een isola$e% "#o, 0ic o" $e s$#uc$u#es,a#ke% on $e sli%e )elo0>


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Q NO 9:A ::4&ea#4ol% o,eless ,ale %e'elo!s con"usion an% o!$al,o!le+ia.U!on #e'ie0 o" $e ,e%ical #eco#% &ou %isco'e# $a$ e as )een a%,i$$e% $o $eos!i$al 0i$ alcool in$o*ica$ion se'e#al $i,es )e"o#e. Wic o" $e "ollo0in+#eac$ions is ,os$ likel& i,!ai#e% in $is !a$ien$>

A. AB. BC. CD. DE. E(. (G. G

199


16/85


Explanation:

Tia,ine se#'es as a co"ac$o# "o# a nu,)e# o" i,!o#$an$ en/&,es inclu%in+$#anske$olase al!a4ke$o+lu$a#a$e %e&%#o+enase an% !u'a$e %e&%#o+enase.Pa$ien$s 0i$ alcoolis, a#e classicall& %e"icien$ in $ia,ine an% a%,inis$#a$ion o"+lucose $o $ese !a$ien$s 0i$ou$ "i#s$ a%,inis$e#in+ a $ia,ine su!!le,en$ #esul$sin $e %e'elo!,en$ o" $e acu$e neu#olo+ical co,!lica$ions o" $ia,ine %e"icienc&kno0n as We#nicke ence!alo!a$&. Clinicall& We#nicke ence!alo!a$& isca#ac$e#i/e% )& acu$e con"usion o!$al,o!le+ia an% a$a*ia. T#ea$,en$ 0i$$ia,ine usuall& #esul$s in !#o,!$ #esolu$ion o" s&,!$o,s.Te )ulk o" ATP use% "o# cellula# !#ocesses is +ene#a$e% )& o*i%a$ion o" !u'a$e$#ou+ $e $#ica#)o*&lic aci% c&cle TCA c&cle3. Te en/&,es o" $e TCA c&cle a#eloca$e% in $e ,i$ocon%#ion. Pu'a$e +ene#a$e% "#o, +l&col&sis is con'e#$e% $oace$&l C6A )& $e en/&,e !u'a$e %e&%#o+enase an% ace$&l CoA $en en$e#s $eTCA c&cle.Te "i#s$ #eac$ion o" $e TCA c&cle is $e con%ensa$ion o" ace$&l4CoA 0i$o*aloace$a$e $o "o#, ci$#a$e coice G3 ca$al&/e% )& $e en/&,e ci$#a$e s&n$ase.

Ci$#a$e is $en con'e#$e% $o isoci$#a$e )& $e en/&,e aconi$ase an i#on sul"u#4con$ainin+ en/&,e. Isoci$#a$e %e&%#o+enase $en %eca#)o*&la$es isoci$#a$e $oal!a4ke$o+lu$a#a$e. Isoci$#a$e %e&%#o+enase is a #a$e li,i$in+ s$e! in $e TCA c&clean% i$ is also $e s$e! 0e#e $e "i#s$ ?ADH is !#o%uce%. Tis en/&,e is ne+a$i'ele+ula$e% )& ?ADH an% ATP an% !osi$i'el& #e+ula$e% )& isoci$#a$e ADP an% AMP.Te con'e#sion o" al!a4ke$o+lu$a#a$e $o succin&l4CoA in'ol'es o*i%a$i'e%eca#)o*&la$ion )& $e en/&,e al!a ke$o+lu$a#a$e %e&%#o+enase coice B3. Tis#eac$ion +ene#a$es a secon% ?ADH. Al!a4ke$o+lu$a#a$e %e&%#o+enase is anen/&,e co,!le* #eui#in+ se'e#al co"ac$o#s inclu%in+ $ia,ine "o# i$s ac$ion.Te con'e#sion o" succin&l4CoA $o succina$e )& succin&l4CoA s&n$e$ase coice C3in'ol'es use o" $e i+4ene#+& $ioes$e# !#esen$ in succin&l4CoA $o %#i'e nucleo$i%e$#i!os!a$e s&n$esis )& a !#ocess kno0n as su)s$#a$e4le'el !os!o#&la$ion. In$is !#ocess i+4ene#+& !os!a$e in$e#,e%ia$es a#e "o#,e% $a$ e'en$uall&!os!o#&la$e GDP $o "o#, GTP.Succin&l %e&%#o+enase coice D3 ca$al&/es $e con'e#sion o" succina$e $o "u,a#a$e0i$ seuen$ial #e%uc$ion o" en/&,e )oun% "la'in a%enine %inucleo$i%e (AD3.(u,a#a$e &%#a$ase "u,a#ase3 ca$al&/es $e "o#,a$ion o" ,ala$e "#o, "u,a#a$ecoice E3. Mala$e is su)seuen$l& con'e#$e% $o o*aloace$a$e )& ,ala$e%e&%#o+enase an% $is is $e "inal s$e! o" $e TCA c&cle coice (3.E%uca$ional O)-ec$i'e842e$o+lu$a#a$e %e&%#o+enase #eui#es $ia,ine as a co"ac$o#. A%,inis$#a$ion o"

+lucose $o $ia,ine %e"icien$ !a$ien$s suc as alcoolics 0ill #esul$ in We#nickeence!alo!a$& %ue $o inc#ease% $ia,ine %e,an%.

200


17/85


A.

Ci$#ulline,iaB. Lac$ic aci%osis

C. Me$&l,alonic aci%u#iaD. Ho,oc&s$inu#iaE. O#o$ic aci%u#ia

Explanation:

201

Q NO 19:An in"an$ su""e#in+ "#o, le$a#+& an% 'o,i$in+ is %ia+nose% 0i$ a%e"icienc& o" se'e#al ,i$ocon%#ial en/&,es. A co,,on su)uni$ con$ainin+li!oic aci% is a)no#,al in $ese en/&,es. Te !a$ien$ is ,os$ likel& $o a'e0ic o" $e "ollo0in+ "in%in+s>


18/85


Coen/&,es an% co"ac$o#s a#e #ela$i'el& s,all ,olecules #eui#e% "o# ,an& en/&,es$o !e#"o#, $ei# ca$al&$ic "unc$ions. Li!oic aci% LA3 is in'ol'e% in $e%eca#)o*&la$ion o" al!a ke$oaci% an% $e $#ans"e# o" alk&l +#ou!s. Te $#ans"e# o" analk&l +#ou! "#o, !u'a$e $o coen/&,e A is essen$ial "o# $e "unc$ion o" !u'a$e%e&%#o+enase PDH3.PDH #eui#es "i'e coen/&,es8 CoA (AD li!oic aci% ?AD an% $ia,ine!o!os!a$e TPP3. In $e a)sence o" $ese coen/&,es PDH is una)le $o ca##& ou$i$s "unc$ion o" con'e#$in+ !u'a$e $o ace$&l CoA "o# ,e$a)olis, in $e TCA c&cle.Dec#ease% "unc$ionin+ o" !u'a$e %e&%#o+enase 0ill inc#ease $e con'e#sion o"!u'a$e $o lac$a$e )& $e en/&,e lac$a$e %e&%#o+enase in an e""o#$ $o #e+ene#a$e?ADI an% $is 0ill e'en$uall& lea% $o lac$ic aci%osis. Li!oic aci% also ac$s as acoen/&,e "o# al!a ke$o+lu$a#a$e %e&%#o+enase an% )#ance%4cain ke$oaci%%e&%#o+enase.Coice A3 Ci$#ulline,ia is a u#ea c&cle %iso#%e# $a$ #esul$s "#o, %e"icienc& o"a#+ininosuccina$e s&n$e$ase. ATP is $e co"ac$o# #eui#e% )& a#+ininosuccina$es&n$e$ase.Coice C3 Me$&l,alonic aci%u#ia o# aci%e,ia #esul$s in aci%e,ia %ue $o inc#ease%

ci#cula$in+ le'els o" ,e$&l,alonic aci% o#+anic aci%e,ia3. Tis +ene#all& #esul$s"#o, a %e"icienc& o" $e 'i$a,in B1@4%e!en%en$ en/&,e ,e$&l ,alona$e ,u$ase.Coice D3 Ho,oc&s$inu#ia #esul$s "#o, a %e"icienc& o" c&s$a$ionine s&n$ase an% isca#ac$e#i/e% )& !#e,a$u#e a$e#oscle#osis. Ho,oc&s$eine is %is!ose% o" )& $e)o%& )& $0o !a$0a&s8 1. con'e#sion $o c&s$eine )& $e co,)ine% ac$ions o" $0o'i$a,in B54#eui#in+ en/&,es c&s$a$ionine s&n$ase an% c&s$a$ionase an% @.con'e#sion $o ,e$ionine )& a "ola$e an% 'i$a,in B1@4%e!en%en$ !#ocess.Coice E3 O#o$ic aci%u#ia occu#s %ue $o %e"ec$i'e !i,i%ine s&n$esis #esul$in+ "#o,a %e"icienc& o" $e en/&,e o#o$a$e !os!o#i)os&l $#ans"e#ase. Tis en/&,e #eui#es+lu$a$ione as a coen/&,e.

E%uca$ional O)-ec$i'e8Li!oic aci% is a co"ac$o# "o# se'e#al ,i$ocon%#ial en/&,es8 PDH %e"icienc& #esul$sin lac$ic aci%osis3 a4ke$o+lu$a#a$e DH an% )#ance%4cain ke$oaci% DH %e"iciencesul$s in ,a!le su! u#ine %isease3.

202


19/85


A.Tia,ine !o!os!a$eB. Pi%o*al !os!a$eC. Li!oic aci%D. Re$inoic aci%E. Bio$in

Explanation:

Lea% is a so"$ ea'& ,e$al use% in $e ,anu"ac$u#e o" a 0i%e #an+e o" i$e,sinclu%in+ )a$$e#ies allo&s an% a,,uni$ion. Te ,os$ si+ni"ican$ ,eans o"occu!a$ional e*!osu#e is inala$ion. Consu,e#s can also )e e*!ose% $o lea% $#ou+con$ac$ 0i$ %us$ in lea%4!ain$e% o,es ol% o,es3 lea%4con$a,ina$e% soil 0a$e#$a$ $#a'e#ses lea% !lu,)in+ lea%4+la/e% !o$$e#& an% o,e,a%e alcoolic)e'e#a+es ,oonsine3. Te ,os$ si+ni"ican$ ,eans o" e*!osu#e "o# $e consu,e# is+as$#oin$es$inal a)so#!$ion.

Lea% o'e#%ose causes $o*ici$& $#ou+ "ou# %is$inc$ ,ecanis,s. Pe#a!s ,os$i,!o#$an$l& lea% as a s$#on+ a""ini$& "o# sul"&%#&l +#ou!s. Tis a""ini$& #esul$s in$e ini)i$ion o" en/&,es $a$ inco#!o#a$e i#on in$o $e e,e ,olecule 74a,inole'ulinic aci% %e&%#a$ase an% "e##oke$olase3. J4a,inole'ulinic aci% is "o#,e%0en succin&l4C6A an% +l&cine co,)ine in $e !#esence o" $e co"ac$o# !i%o*al!os!a$e. Te )loo% an% u#ina#& le'els o" $is en/&,e a#e inc#ease% in in%i'i%uals0i$ lea% !oisonin+.Coice A3 Tia,ine !o!os!a$e is an essen$ial 'i$a,in Bi4%e#i'e% co"ac$o# $a$!la&s a #ole in ,ul$i!le !a$0a&s o" ene#+& ,e$a)olis, e+ !u'a$e an% a4ke$o+lu$a#a$e %e&%#o+enase ca$al&/e% #eac$ions3.Coice C3 Li!oic aci% o# li!oa$e is an essen$ial co"ac$o# in nu,e#ous "ace$s o"ae#o)ic ,e$a)olis, e+ $#ans"e# o" ac&l an% ,e$&la,ine +#ou!s in @4o*oaci%%e&%#o+enase an% +l&cine clea'a+e co,!le*es #es!ec$i'el&3. I$ is also anan$io*i%an$ ca!a)le o" sca'en+in+ #eac$i'e o*&+en s!ecies an% #e%ucin+ ,e$a)oli$es.Coice D3 Re$inoic aci% )in%s $o #ece!$o# !#o$eins an% $e su)seuen$ #e$inoic aci%4!#o$ein co,!le* in$e#ac$s 0i$ an% a""ec$s e*!#ession o" nu,e#ous +enes $a$ a""ec$+#o0$ an% %i""e#en$ia$ion.Coice E3 Bio$in is $e co"ac$o# necessa#& "o# ,an& #eac$ions in'ol'in+ ca#)o*&la$ionen/&,es e+ ace$&l4CoA ca#)o*&lase an% !u'a$e ca#)o*&lase3.


Pi%o*al !os!a$e is a necessa#& co"ac$o# in $e s&n$esis o" K4a,inole'ulinic aci%0ic is ele'a$e% in cases o" lea% !oisonin+3.

203

Q NO 11:A 54&ea#4ol% ,ale 0o li'es in an ol% ouse su""e#s "#o, i##i$a)ili$&cons$i!a$ion an% ane,ia. His i+ )loo% le'el o" K4a,inole'ulinic aci% is,ain$aine% secon%a#& $o $e !#esence o" 0ic o" $e "ollo0in+ co"ac$o#s>


20/85


A.

Ca#)on %io*i%eB. @ 94)i!os!o+l&ce#a$eC. Ca#)on ,ono*i%eD. C&ani%eE. lo#nE. Lea%

Explanation:

C&ani%e )in%s $o a 'a#ie$& o" i#on4con$ainin+ en/&,es $e ,os$ i,!o#$an$ o" 0icis $e c&$oc#o,e a4a9 co,!le*. Tis co,!le* is c#i$ical "o# elec$#on $#ans!o#$ %u#in+o*i%a$i'e !os!o#&la$ion. B& )in%in+ $o $is ,olecule ,inu$e a,oun$s o" c&ani%e

can ini)i$ ae#o)ic ,e$a)olis, an% #a!i%l& #esul$ in %ea$.Te $&!ical clinical s&n%#o,e !#esen$ in c&ani%e !oisonin+ is #a!i%l&4%e'elo!in+cu$aneous "lusin+ $ac&!nea ea%ace an% $ac&ca#%ia o"$en acco,!anie% )&nauseaF'o,i$in+ con"usion an% 0eakness. Res!i#a$o#& %is$#ess an% ca#%iac%&s"unc$ion ,a& "ollo0. La)o#a$o#& s$u%ies in%ica$e se'e#e lac$ic aci%osis incon-unc$ion 0i$ a lessene% %i""e#ence )e$0een a#$e#ial an% 'enous con$en$ i.e. $e'enous )loo% is s$ill i+l& o*&+ena$e%3.

Te an$i%o$al e""ec$ o" ni$#i$es "o# c&ani%e !oisonin+ as )een #eco+ni/e% since $e

la$e nine$een$ cen$u#&. ?i$#i$es a#e o*i%i/e#s an% ac$ !#i,a#il& in c&ani%e !oisonin+)& in%ucin+ $e "o#,a$ion o" ,e$e,o+lo)in. Tis occu#s 0en "e##ous i#on ine,o+lo)in is o*i%i/e% $o "e##ic i#on. Me$e,o+lo)in canno$ ca##& o*&+en )u$ i$%oes a'e a i+ a""ini$& "o# c&ani%e. Me$e,o+lo)in can )in% an% seues$e# c&ani%ein $e )loo% $e#e)& kee!in+ $e !oison a0a& "#o, ,i$ocon%#ial an% o$e#3en/&,es 0e#e c&ani%e e*e#$s i$s $o*ic e""ec$s. So%iu, $iosul"a$e is also use% "o#c&ani%e !oisonin+8 i$ co,)ines 0i$ c&ani%e $o "o#, $e less4$o*ic $ioc&ana$e0ic is e*c#e$e% in $e u#ine.Coices A B an% C3 Me$e,o+lo)in 0ic is "o#,e% 0en a,&l ni$#i$e isa%,inis$e#e% %oes no$ a'e a i+ a""ini$& "o# ,olecules suc as ca#)on ,ono*i%eca#)on %io*i%e an% @9 )is!os!o+l&ce#a$e.

Coice E3 Te a""ini$& o" e,o+lo)in "o# i#on is no$ a""ec$e% )& ni$#i$ea%,inis$#a$ion $ou+ ni$#i$es %o o*i%i/e $e e,e i#on $o i$s (e III3 s$a$e.

204

Q NO 12:A @14&ea#4ol% la)o#a$o#& 0o#ke# e*!e#iences #a!i%4onse$ )#ea$in+%i""icul$& !al!i$a$ions an% "luse% skin. He as no si+ni"ican$ !as$ ,e%icalis$o#& an% $akes onl& lo#a$a%ine "o# seasonal alle#+ies. Te !a$ien$ issus!ec$e% $o a'e acci%en$al !oisonin+. A,&l ni$#i$e "#o, a la)o#a$o#& sa"e$&ki$ is i,,e%ia$el& a%,inis$e#e% 'ia inala$ion. A,&l ni$#i$e a""ec$s $e a""ini$&o" e,o+lo)in "o# 0ic o" $e "ollo0in+>


21/85


Coice (3 Lea% !oisonin+ causes %e"ec$i'e e,e s&n$esis. Lea% !oisonin+ is$#ea$e% "i#s$ an% "o#e,os$ )& $e a'oi%ance o" lea% in+es$ion. I" acu$el& in+es$e%cela$ion $e#a!& suc as 0i$ %i,e#ca!#ol o# Ca?aEDTA soul% )e ini$ia$e%.

E%uca$ional O)-ec$i'e8?i$#i$es a#e o*i%i/in+ a+en$s $a$ a#e e""ec$i'e in $e $#ea$,en$ o" c&ani%e !oisonin+%ue $o $ei# a)ili$& $o cause ,e$e,o+lo)ine,ia. Me$e,o+lo)in con$ains "e##ic#a$e# $an "e##ous i#on. C&ani%e )in%s $o "e##ic i#on ,o#e a'i%l& $an $o,i$ocon%#ial c&$oc#o,e en/&,es 0ic sa'es $ese ,i$ocon%#ial en/&,es "#o,c&ani%e=s $o*ic e""ec$.

205


22/85


A.

Tia,ineB. Ri)o"la'inC. (olic aci%D. ?iacinE. Pi%o*ine(. Toco!e#olG. Asco#)a$e

Explanation:A$ leas$ $#ee s!eci"ic s,all )o0el en$e#oc&$e a!ical $#ans!o#$ !#o$eins a!!ea# $o )ein'ol'e% in $e a)so#!$ion o" a,ino aci%s "#o, $e %ie$. In Ha#$nu! %isease $ein$es$inal an% #enal a)so#!$ion o" $#&!$o!an is %e"ec$i'e. T#&!$o!an is an essen$iala,ino aci% an% a !#ecu#so# "o# nico$inic aci% se#o$onin an% ,ela$onin. Te clinical

,ani"es$a$ions o" Ha#$nu! %isease a#e !#i,a#il& %ue $o $e ,ala)so#!$ion o"$#&!$o!an #esul$in+ in niacin i$a,in B93 %e"icienc& )ecause niacin is s&n$esi/e%"#o, $#&!$o!an.Mos$ cil%#en 0i$ Ha#$nu! %isease a#e as&,!$o,a$ic )u$ so,e cil%#en e*!e#ience!o$osensi$i'i$& an% !ella+#a4like skin #ases as in $e case %esc#i)e% a)o'e.?eu#olo+ic in'ol'e,en$ can occu# ,os$ co,,onl& lea%in+ $o a$a*ia. ?eu#olo+ic an%skin s&,!$o,s $&!icall& 0as an% 0ane %u#in+ $e cou#se o" $is %isease. Te ,ainla)o#a$o#& "in%in+ in Ha#$nu! %isease is a,inoaci%u#ia #es$#ic$e% $o $e neu$#ala,ino aci%s alanine se#ine $#eonine 'aline leucine isoleucine !en&lalanine$osine $#&!$o!an an% is$i%ine3. Te u#ina#& e*c#e$ion o" !#oline &%#o*&!#olinean% a#+inine #e,ains uncan+e% an% $is i,!o#$an$ "in%in+ %i""e#en$ia$es Ha#$nu!%isease "#o, o$e# causes o" +ene#ali/e% a,inoaci%u#ia suc as (anconi s&n%#o,e.T#ea$,en$ 0i$ nico$inic aci% o# nico$ina,i%e an% a i+4 !#o$ein %ie$ +ene#allesul$s in si+ni"ican$ i,!#o'e,en$ o" s&,!$o,s.Coice A3 Tia,ine use )& $e )o%& is ,a*i,al in s$a$es o" accele#a$e%ca#)o&%#a$e ,e$a)olis, )ecause i$ ac$s as a co"ac$o# "o# $e en/&,e $#anske$olasein $e !en$ose !os!a$e !a$0a& as 0ell as $e en/&,es a4ke$o+lu$a#a$e%e&%#o+enase an% !u'a$e %e&%#o+enase )o$ o" 0ic #eui#e $ia,ine as aco"ac$o#.Coice B3 Te coen/&,es "la'in ,ononucleo$i%e (M?3 an% "la'in a%enine%inucleo$i%e (AD3 "o#, $e !#os$e$ic +#ou!s o" se'e#al en/&,es i,!o#$an$ in

elec$#on $#ans!o#$. Bo$ "la'in ,ononucleo$i%e (M?3 an% "la'in a%enine %inucleo$i%e(AD3 a#e s&n$esi/e% "#o, #i)o"la'in i$a,in B@3. Clinical "ea$u#es o" #i)o"la'in%e"icienc& inclu%e ceilosis !e#lce3 +lossi$is ke#a$i$is con-unc$i'i$is!o$o!o)ia lac#i,a$ion ,a#ke% co#neal 'ascula#i/a$ion an% se)o##eic %e#,a$i$is.Coice C3 (olic aci% %e"icienc& ,a& #esul$ in ,e+alo)las$ic ane,ia )u$ %oes no$#esul$ in $e neu#olo+ical ,ani"es$a$ions o" su)acu$e co,)ine% %e+ene#a$ion o" $e!os$e#io# an% la$e#al colu,ns seen s!eci"icall& 0i$ 'i$a,in B1@ %e"icienc&.Coice E3 Pi%o*ine i$a,in B3 is con'e#$e% $o !i%o*al474!os!a$e 0ic ac$sas a coen/&,e in $e %eca#)o*&la$ion an% $#ansa,ina$ion o" a,ino aci%s. De"icienc&o" !i%o*ine lea%s $o ane,ia !e#i!e#al neu#o!a$& an% %e#,a$i$is.Coice (3 Toco!e#ol i$a,in E3 is a "a$4solu)le 'i$a,in $a$ "unc$ions as asca'en+e# o" "#ee #a%icals an$io*i%an$3. De"icienc& o" i$a,in E is 'e#& unco,,on)u$ 0en i$ occu#s i$ can #esul$ in ,&elo!a$& o# neu#olo+ic %&s"unc$ion.

206

Q NO 13:A 1@4&ea#4ol% ,ale is e'alua$e% "o# a$a*ia acco,!anie% )& e!iso%ice#&$e,a$ous an% !#u#i$ic skin lesions an% loose s$ools. La)o#a$o#& e'alua$ion#e'eals loss o" neu$#al a#o,a$ic a,ino aci%s in $e u#ine. Tis !a$ien$=ss&,!$o,s 0oul% ,os$ likel& #es!on% $o 0ic o" $e "ollo0in+ su!!le,en$s>


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E%uca$ional O)-ec$i'e8Ha#$nu! %isease can #esul$ in niacin %e"icienc& %ue $o an e*cess loss o" %ie$a#&$#&!$o!an #esul$in+ "#o, %e"ec$i'e in$es$inal an% #enal $u)ula# a)so#!$ion o" $a$a,ino aci%. Re,e,)e# $a$ niacin nico$ina,i%e F i$a,in B93 is s&n$esi/e% "#o,$#&!$o!an an% $a$ $#&!$o!an is an essen$ial a,ino aci%.

207


24/85


A.

Coles$e#olB. Ca#o$eneC. T#&!$o!anD. Pen&lalanineE. A#+inineE. O#o$ic aci%

Explanation:

Pella+#a 0ic ,eans ;#ou+ skin< in I$alian 'e#nacula#3 is a clinical s&n%#o,ea#isin+ secon%a#& $o niacin %e"icienc& $a$ is ca#ac$e#i/e% )& $e ;$#ee Ds


25/85


A. i$a,in AB. i$a,in 2C. i$a,in DD. i$a,in EE. i$a,in B1@(. i$a,in B5

Explanation:Al$ou+ #a#e in $e Uni$e% S$a$es an% o$e# in%us$#iali/e% na$ions 'i$a,in A%e"icienc& is #ela$i'el& co,,on in Asia A"#ica an% Sou$ A,e#ica. Malnou#is,en$an% "a$ ,ala)so#!$ion e+ c&s$ic "i)#osis coles$a$ic li'e# %isease3 a#e $e ,os$si+ni"ican$ causes o" 'i$a,in A %e"icienc&. Clinical ,ani"es$a$ions o" $e con%i$ion

inclu%e ni+$ )lin%ness co,!le$e )lin%ness an% *e#o!$al,ia. Mo#e unusual "in%in+sinclu%e Bi$o$=s s!o$s a)no#,al sua,ous cell !#oli"e#a$ion an% ke#a$ini/a$ion o" $econ-unc$i'a3 co#neal !e#"o#a$ion ke#a$o,alacia nons!eci"ic %e#,a$olo+ica)no#,ali$ies an% u,o#al an% cell4,e%ia$e% i,,une s&s$e, ini)i$ion 'ia %a,a+e%one $o !a+oc&$es an% T cell l&,!oc&$es. Dea$ can #esul$ i" $e con%i$ion isun$#ea$e%.Resea#c as %e,ons$#a$e% $a$ 'i$a,in A is o" )ene"i$ in $#ea$in+ cil%#en a""lic$e%0i$ ,easles. S!eci"icall& 'i$a,in A $e#a!& #e%uces $e $i,e $o #eco'e#& "#o,!neu,onia an% %ia##ea as 0ell as $e len+$ o" os!i$al s$a& an% #isk o" %ea$. I$as )een !os$ula$e% $a$ $e 'i$a,in A #esol'es a 'i#all&4in%uce% &!o#e$ine,ia$ou+ $is as no$ &e$ )een con"i#,e%. Te WHO #eco,,en%s $a$ 'i$a,in A )ea%,inis$e#e% $o all cil%#en 0i$ ,easles in a#eas 0i$ 0i%es!#ea% 'i$a,in A%e"icienc& o# in a#eas 0i$ a ,easles ,o#$ali$& #a$e in e*cess o" one !e#cen$.Coices B C D E an% (3 i$a,ins 2 D E an% B %o no$ a!!ea# $o )e o" %i#ec$)ene"i$ in $e $#ea$,en$ o" ,easles in"ec$ion.

E%uca$ional O)-ec$i'e8i$a,in A can )e o" )ene"i$ in $e $#ea$,en$ o" ,easles in"ec$ion.

209

Q NO 15:A @64,on$4ol% ,ale is )#ou+$ $o ER 0i$ i+ "e'e# con"usion an% askin #as su++es$i'e o" ,easles. He as a is$o#& o" #ecu##en$ #es!i#a$o#&in"ec$ions o'e# $e las$ 5 ,on$s. Te !a$ien$=s "a,il& as #ecen$l& e,i+#a$e%"#o, a #u#al Russian !#o'ince. Wic o" $e "ollo0in+ "o#,s o" 'i$a,insu!!le,en$a$ion soul% )e consi%e#e% in $is !a$ien$>


26/85


A. i$a,in B1B. i$a,in B@C. Pi%o*ineD. (olio aci%E. Asco#)ic aci%(. i$a,in 2G. inc

Explanation:i$a,in C canno$ )e s&n$esi/e% en%o+enousl& an% $e#e"o#e ,us$ )e consu,e% in$e u,an %ie$. Tis is $&!icall& no$ a !#o)le, as asco#)ic aci% is a)un%an$l& "oun%in "#ui$s an% 'e+e$a)les 0ile also )ein+ !#esen$ $o a lesse# e*$en$ in ,ilk li'e# an%"is3. De"iciencies o" 'i$a,in C a#e $e#e"o#e #a#e in %e'elo!e% coun$#ies )u$

con$inue $o )e a conce#n in $ose 0i$ inconsis$en$ ea$in+ !a$$e#ns inclu%in+ $eel%e#l& alcoolics an% !e#sons 0o li'e alone.i$a,in C asco#)ic aci%3 %e"icienc& e'en$uall& #esul$s in scu#'& a %iseaseca#ac$e#i/e% )& e,o##a+es su)!e#ios$eal e,a$o,as )lee%in+ in$o -oin$ s!aces+in+i'al s0ellin+ secon%a#& !e#io%on$al in"ec$ion ane,ia &!e#ke#a$o$ic !a!ula##ases i,!ai#e% 0oun% ealin+ an% 0eakene% i,,une #es!onse $o local in"ec$ions.Because asco#)ic aci% accele#a$es &%#o*&la$ion an% a,i%a$ions #eac$ions i$ !la&s ac#ucial #ole in nu,e#ous )ios&n$e$ic !a$0a&s. One o" $e ,os$ i,!o#$an$ "unc$ionso" asco#)ic aci% is i$s ac$i'a$ion o" !#ol&l an% l&s&l &%#o*&lase !#ecu#so#s )o$ o"0ic a#e necessa#& "o# $e &%#o*&la$ion o" !#ocolla+en. As colla+en con$ainsconsi%e#a)le &%#o*&!#oline $e uan$i$& an% uali$& o" $e colla+en !#o%uce% is%#a,a$icall& i,!ai#e% )& an& #e%uc$ion in a'aila)le asco#)ic aci%.Coice A3 i$a,in B1 $ia,ine3 %e"icienc& is ca#ac$e#i/e% )& )e#i)e#i an%We#nicke s&n%#o,e.Coice B3 i$a,in B@ #i)o"la'in3 %e"icienc& is ca#ac$e#i/e% )& ceilosis s$o,a$i$is+lossi$is %e#,a$i$is co#neal 'ascula#i/a$ion an% a#i)o"la'inosis.Coice C3 Pi%o*ine 'i$a,in B53 %e"icienc& is ca#ac$e#i/e% )& ceilosis +lossi$is%e#,a$i$is an% !e#i!e#al neu#o!a$&.Coice D3 (olic aci% %e"icienc& is ca#ac$e#i/e% )& ,e+alo)las$ic ane,ia an% neu#al$u)e %e"ec$s in $e "e$us.Coice (3 i$a,in 2 %e"icienc& is ca#ac$e#i/e% )& a )lee%in+ %ia$esis )u$ no$

!ain"ul +u,s3.Coice G3 inc %e"icienc& is ca#ac$e#i/e% )& ac#o%e#,a$i$is en$e#o!a$ica +#o0$#e$a#%a$ion an% in"e#$ili$&.

E%uca$ional O)-ec$i'e8Te s&,!$o,s o" scu#'& a#e !#i,a#il& cause% )& i,!ai#e% colla+en "o#,a$ion an%inclu%e e,o##a+es su)!e#ios$eal e,a$o,as )lee%in+ in$o -oin$ s!aces +in+i'als0ellin+ secon%a#& !e#io%on$al in"ec$ion ane,ia &!e#ke#a$o$ic !a!ula# #asesi,!ai#e% 0oun% ealin+ an% 0eakene% i,,une #es!onse $o local in"ec$ions.

210

Q NO 16:A N4&ea#4ol% "e,ale !#esen$s $o &ou# o""ice 0i$ le+ !ain an% "a$i+ue.Se li'es alone an% as li$e ,one& $o s!en% on "oo%. Te !a$ien$ as $i)ialsu)!e#ios$eal e,a$o,as an% !ain"ul +u,s. Wic o" $e "ollo0in+ nu$#ien$%e"iciencies is ,os$ likel& #es!onsi)le "o# $is !a$ien$=s s&,!$o,s>


27/85


A. I$ cu$s D?A a$ s!eci"ic D?A seuencesB. I$ nicks $e D?A s$#an%s $a$ a'e "o#,e% $&,i %ine %i,e#sC. I$ #e,o'es an i,!#o!e# )ase4!ai# nucleo$i%e %u#in+ #e!lica$ionD. I$ clea'es D?A s$#an%s $o #ela* !osi$i'e su!e#coilsE. I$ can #e,o'e +#ou!s o" nucleo$i%es u! $o $en3 a$ a $i,e

Explanation:

Du#in+ $e !#ocess o" cell %i'ision D?A #e!lica$ion occu#s secon%a#& $o $ecoo#%ina$e% e""ec$s o" ,ul$i!le en/&,es an% !#o$eins. D?A !ol&,e#ases a#e $e!#i,a#& en/&,es #es!onsi)le "o# D?A #e!lica$ion )u$ $e& can no$ "unc$ion 0i$ou$

$e assis$ance o" o$e# en/&,es suc as !#i,ase elicase li+ase an%$o!oiso,e#ase I an% II. In E. coil $e#e a#e $#ee !#i,a#& $&!es o" D?A!ol&,e#ases8 D?A !ol&,e#ase I II an% Ill. P#i,ase "o#,s $e 9= OH +#ou! !#i,e# $oini$ia$e #e!lica$ion o" %au+$e# s$#an%s 0ile elicase !#o,o$es un0in%in+ an%%issocia$ion o" $e !a#en$ s$#an%s. On $e o$e# an% $o!oiso,e#ases #e%uce!osi$i'e an% ne+a$i'e su!e# coilin+ in o#%e# $o #elie'e $e s$#ain !#o%uce% )& D?Aun0in%in+.D?A #e!lica$ion #eui#es a i+ %e+#ee o" "i%eli$& $e#e"o#e as s&n$esis o" $e%au+$e# s$#an%s !#ocee%s D?A !ol&,e#ases !#oo" #ea% $o ensu#e $a$ $e %au+$e#D?A is $e e*ac$ co,!le,en$ o" $e !a#en$ D?A. All $#ee !#oka#&o$ic D?A!ol&,e#ases a'e !#oo" #ea%in+ ac$i'i$& an% #e,o'e ,is,a$ce% nucleo$i%es 'ia a 9=$o 7= e*onuclease ac$i'i$& Coice C3. Onl& D?A !ol&,e#ase I as 7= $o 9=e*onuclease ac$i'i$& 0ic is use% $o e*cise an% #e!lace R?A !#i,e#s an% %a,a+e%D?A seuences 0ic a#e i%en$i"ie% )& en%onucleases Coice E3.

211

Q NO 17:So,e !#o$eins $a$ !a#$ici!a$e in )ac$e#ial D?A s&n$esis a'e s!eci"ice*onuclease ac$i'i$&. Wic o" $e "ollo0in+ is $e )es$ s$a$e,en$ a)ou$ $e 9= $o7= e*onuclease ac$i'i$& o" D?A !ol&,e#ase Ill>


28/85


Coice A3 In con$#as$ $o e*onucleases 0ic #e,o'e nucleo$i%es "#o, $e en% o" aD?A ,olecule en%onucleases cu$ D?A a$ 'e#& s!eci"ic D?A seuences 0i$in $e,olecule. Res$#ic$ion en%onucleases %i+es$ D?A in$o s,alle# "#a+,en$s in aseuence4s!eci"ic ,anne#.Coice B3 One o" $e ,a-o# ,e$o%s o" D?A %a,a+e )& ul$#a'iole$ li+$ is $e%i,e#i/a$ion o" a%-acen$ !i,i%ine )ases $o "o#, $&,i%ine %i,e#s. Tese %i,e#sa#e #ou$inel& "o#,e% a"$e# e*!osu#e $o sunli+$ )u$ a#e usuall& #e,o'e% )&!#o$ec$i'e en/&,a$ic ,ecanis,s.

E%uca$ional O)-ec$i'e8All $#ee !#oka#&o$ic D?A !ol&,e#ases a'e !#oo" #ea%in+ ac$i'i$& an% #e,o'e,is,a$ce% nucleo$i%es 'ia 9= $o 7= e*onuclease ac$i'i$&. Onl& D?A !ol&,e#ase I as7= $o 9= e*onuclease ac$i'i$& 0ic is use% $o e*cise an% #e!lace R?A !#i,e#s an%%a,a+e% D?A seuences.

212


29/85


A.Te& ac$ )& ac$i'a$ion o" $osine kinase.B. Te& ac$ !#i,a#il& )& ac$i'a$ion o" a%en&l&l c&clase.C. Te& a'e a nuclea# #ece!$o#.D. Te& a'e a c&$o!las,ic #ece!$o#.E. Te& ac$ )& inc#easin+ $e ac$i'i$& o" !os!oli!ase C.

Explanation:

Te ac$ions o" $oi% o#,ones a#e ,e%ia$e% )& $oi% o#,one #ece!$o#s 0ica#e loca$e% ac$uall& 0i$ in $e nucleus. ?uclea# #ece!$o#s con$#ol +ene e*!#ession)& )in%in+ $o D?A a$ o#,one4#es!onsi'e ele,en$s in $e !#o,o$e# #e+ion o" $a#+e$+enes. O$e# ,olecules $a$ ac$ $#ou+ nuclea# #ece!$o#s inclu%e #e$inoi%s!e#o*iso,al !#oli"e#a$in+ ac$i'a$e% #ece!$o#s an% "a$$& aci%s.Coice A3 Tosine4kinase4ac$i'a$in+ #ece!$o#s a#e loca$e% on $e cell=s su#"ace an%usuall& a'e an e*$#acellula# %o,ain "o# li+an% )in%in+ o# $#ans ,e,)#ane #e+ion

an% ca#)o*&4$e#,inal %o,ain con$ainin+ $osine kinase ac$i'i$&. Insulin an% 'a#ious+#o0$ "ac$o#s suc as e!i%e#,al +#o0$ "ac$o# an% $#ans"o#,in+ +#o0$ "ac$o#4)e$a 0o#k $#ou+ ac$i'a$ion o" $osine kinase.Coices B an% E3 Se'e#al !e!$i%e o#,ones +luca+on PTHI ACTHI an%+ona%o$#o!ins3 ac$ 'ia $ese S4!#o$ein4 cou!le% ,e,)#ane4)oun% #ece!$o#s. Tese#ece!$o#s $&!icall& a'e se'en $#ans,e,)#ane #e+ions s!annin+ $e !las,a,e,)#ane 0i$ one a,ino4$e#,inal %o,ain an% one ca#)o*&4$e#,inal %o,ain. Tee*$#acellula# a,ino4 $e#,inal %o,ain is #es!onsi)le "o# o#,one )in%in+ 0en $isoccu#s $e c&$o!las,ic ca#)o*&1e#,inal ac$uall& ac$i'a$es S4!#o$ein 0ic in $u#ninc#eases secon% ,essen+e#s suc as c&clic AMP )& ac$i'a$ion o" a%en&l&l c&claseac$i'i$&. S4!#o$ein can also inc#ease !os!oli!ase C ac$i'i$& #esul$in+ in "o#,a$ion o"o$e# secon%4,essen+e#s like inosi$ol 1 .:74$n !os!a$e an% %iac&l+l&ce#ol DAG3.Coice D3 Rece!$o#s "o# se'e#al s$e#oi% o#,ones suc as +lucoco#$icoi%s,ine#aloco#$icoi%s an%#o+ens an% es$#o+ens a#e loca$e% !#i,a#il& in $e c&$o!las,.

E%uca$ional O)-ec$i'e8Toi% o#,ones al$e# +ene $#ansc#i!$ion )& )in%in+ $o #ece!$o#s si$ua$e% insi%e o"$e nucleus. Rece!$o#s "o# se'e#al s$e#oi% o#,ones suc as +lucoco#$icoi%s,ine#aloco#$icoi%s an%#o+ens an% es$#o+ens a#e usuall& ini$iall& !#esen$ inc&$o!las, al$ou+ $e& %o ,i+#a$e $o $e nucleus once ac$i'a$e%.

213

Q NO 18:A 964&ea#4ol% "e,ale is %ia+nose% 0i$ Hasi,o$o=s $oi%i$is an%su)seuen$l& s$a#$e% on $oi%4#e!lace,en$ $e#a!&. Wic o" $e "ollo0in+is $#ue a)ou$ $oi% o#,ones>


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A. (i)#illinB. La,ininC. (i)#onec$inD. Colla+enE. 2e#a$in(. Elas$in

Explanation:Te colla+en ,olecule consis$s o" $#ee !ol&!e!$i%e al!a cains el% $o+e$e# )&&%#o+en )on%s $o "o#, a #o!e4like $#i!le eli* s$#uc$u#e. Te 'a#ia$ion in a,ino aci%seuences in $e colla+en al!a cains +i'es #ise $o colla+en %i'e#si$& in %i""e#en$$issues. (o# e*a,!le $&!e colla+en is !#esen$ in skin )ones $en%ons )loo% 'essels

an% $e co#nea. In $ese $issues colla+en !#o'i%es $ensile s$#en+$ an% alon+ 0i$ke#a$in is #es!onsi)le "o# skin s$#en+$ an% elas$ici$&.Ele#s4Danlos s&n%#o,e EDS3 is a +#ou! o" #a#e e#e%i$a#& %iso#%e#s in'ol'in+connec$i'e $issues "oun% in skin $en%ons li+a,en$s an% ,uscles. EDS usuall&,ani"es$s clinicall& as o'e#4"le*i)le &!e#,o)ile3 -oin$s o'e#4elas$ic &!e#elas$ic3skin an% "#a+ile $issue susce!$i)le $o )#uisin+ 0oun%in+ an% e,a#$#osis. EDS#esul$s "#o, e#i$a)le %iso#%e#s o" colla+en ,e$a)olis,. Te#e a#e se'e#al %i""e#en$$&!es o" EDS %e"ine% )& $e e*$en$ o" in'ol'e,en$ o" skin -oin$s an% o$e# $issues.Co,,on ,u$a$ions lea%in+ $o EDS !eno$&!es inclu%e %e"iciencies o" $e l&s&l&%#o*&lase an% !#o4colla+en !e!$i%ase en/&,es #es!onsi)le "o# colla+en s&n$esis.Coice A3 (i)#illin4 is a ,a-o# co,!onen$ o" $e ,ic#o "i)#ils $a$ "o#, a sea$a#oun% elas$in. Mic#o"i)#ils a#e a)un%an$l& !#esen$ in )loo% 'essels an% $esus!enso#& li+a,en$s o" $e lens. De"ec$s in $e "i)#illin4 +ene cause classicau$oso,al %o,inan$ Ma#"an=s s&n%#o,e.Coice B3 La,inins a#e e$e#o$#i,e#ic +l&co!#o$eins $a$ )in% $o $&!e I colla+enun%e#l&in+ e!i$elial cells. Te& con$#i)u$e $o $e o#+ani/a$ion an% "unc$ion o" $e)asal la,ina )ase,en$ ,e,)#ane3.Coice C3 (i)#onec$in )in%s $o in$e+#ins on $e cell su#"ace an% on co,!onen$s o"$e e*$#acellula# ,a$#i* suc as colla+en an% "i)#in. I$ "unc$ions as an a%esi'e!#o$ein in'ol'e% in cellula# %i""e#en$ia$ion !a+oc&$osis !la$ele$ a%esion an%$#o,)us "o#,a$ion.

Coice E3 2e#a$in is $e ,a-o# !#o$ein co,!onen$ o" ai# an% nails in u,ans.2e#a$in is co,!ose% o" la#+e a,oun$s o" alanine an% +l&cine $a$ )ecause o" $ei#s,all s$#uc$u#e a#e a)le $o coil $i+$l& an% "o#, la#+e nu,)e#s o" &%#o+en )on%s.A%%i$ionall& ke#a$in con$ains a si+ni"ican$ a,oun$ o" $e sul"u#4con$ainin+ a,ino aci%c&s$eine an% "o#,a$ion o" %isul"i%e )on%s )e$0een c&s$eine #esi%ues +i'es a%%i$ional#i+i%i$& an% $ou+ness $o $e !#o$ein. Te la#+e a,oun$ o" ke#a$in in e!i$elial cellso" skin ,akes $e ou$,os$ la&e# o" skin 0a$e#!#oo". A %e"ec$ in ke#a$ins 7 an% 1:#esul$s in e!i%e#,ol&sis )ullosa si,!le*.Coice (3 Elas$in is a "i)#ous !#o$ein in $e connec$i'e $issue $a$ +e$s i$s na,e)ecause o" i$s elas$ic !#o!e#$ies. Elas$in "i)e#s can )e s$#e$ce% $o se'e#al $i,es $ei#o#i+inal len+$ )u$ 0ill #ecoil 0en s$#e$cin+ "o#ces a#e 0i$%#a0n. Elas$in iss&n$esi/e% "#o, a !ol&!e!$i%e !#ecu#so# $#o!oelas$in. Elas$in +i'es elas$ic!#o!e#$ies $o skin )loo% 'essels an% lun+ al'eoli.

214

Q NO 19:Te 1@4&ea#4ol% son o" a ci#cus con$o#$ionis$ sa&s $a$ is skin sca#s an%)#uises easil&. P&sical e*a,ina$ion #e'eals %is$ensi)le skin an% &!e#,o)ile -oin$s.You sus!ec$ an ine#i$e% %e"ec$ in 0ic o" $e "ollo0in+ ,olecules>


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E%uca$ional O)-ec$i'e8Ele#s4Danlos s&n%#o,e is a e#i$a)le connec$i'e $issue %isease $&!icall& associa$e%0i$ a)no#,al colla+en. EDS usuall& ,ani"es$s clinicall& as o'e#4"le*i)le&!e#,o)ile3 -oin$s o'e#4elas$ic &!e#elas$ic3 skin an% "#a+ile $issue susce!$i)le $o)#uisin+ 0oun%in+ an% e,a#$#osis.

215


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A. Glucose $o !u'a$eB. Glucose $o #i)ose474!os!a$eC. Alanine $o +lucoseD. O*aloace$a$e $o ci$#a$e(. Glu$a,a$e $o a4ke$o+lu$a#a$e

Explanation:Te )iolo+icall& ac$i'e "o#, o" !an$o$enic aci% is coen/&,e A an essen$ial co"ac$o#in nu,e#ous ace$&la$ion #eac$ions inclu%in+ $ose associa$e% 0i$ $e $#ica#)o*&licaci% TCA3 c&cle. Coen/&,e A is !a#$icula#l& i,!o#$an$ in $e "i#s$ s$e! o" $e TCAc&cle as i$ )in%s 0i$ o*aloace$a$e $o "o#, ci$#a$e an% $en succin&l4CoA. Coen/&,e

A is also i,!o#$an$ in $e s&n$esis o" 'i$a,in A 'i$a,in D coles$e#ol s$e#oi%se,e A "a$l& aci%s a,ino aci%s an% !#o$eins.Te !an$o$enic aci% is ac$i'el& $#ans!o#$e% in$o $e cell an% $en un%e#+oes ATP4%e!en%en$ !os!o#&la$ion 0ic $#ans"o#, i$ in$o coen/&,e A.De"icienc& o" !an$o$enic aci% is #a#e $ou+ i$ as )een o)se#'e% in se'e#el&,alnou#ise% !eo!le 0o co,!lain o" !a#es$esias an% %&ses$esias ;)u#nin+ "ee$s&n%#o,e


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A.GlucoseB. (#uc$oseC. Galac$oseD. Galac$i$olE. &lulose

Explanation:

Al%ose #e%uc$ase con'e#$s +lucose in$o so#)i$ol. So#)i$ol canno$ #ea%il& c#oss cell,e,)#anes an% is $e#e"o#e $#a!!e% insi%e $e cells 0i$in 0ic i$ is "o#,e%. I" $een/&,e so#)i$ol %e&%#o+enase is also !#esen$ in $e cell i$ can con'e#$ so#)i$ol in$o"#uc$ose. Tis !a$0a& is es!eciall& ac$i'e in $e se,inal 'esicles as s!e#, use"#uc$ose as $ei# !#i,a#& ene#+& sou#ce.O$e# $issues suc as $e lens #e$ina Sc0ann cells an% ki%ne&s a'e a ,uc lo0e#ac$i'i$& o" so#)i$ol %e&%#o+enase. Wen $e le'el o" +lucose is lo0 $e lo0 ac$i'i$&

o" $is en/&,e is su""icien$ $o con'e#$ so#)i$ol in$o "#uc$ose an% %isallo0 so#)i$olaccu,ula$ion 0i$in cells. In s$a$es o" lon+4s$an%in+ &!e#+l&ce,ia suc as inuncon$#olle% %ia)e$es ,elli$us o0e'e# an e*cessi'e a,oun$ o" so#)i$ol is !#o%uce%an% $#a!!e% in $ese cells. Te i+ concen$#a$ion o" so#)i$ol 0i$in $ese cellsinc#eases $e os,o$ic !#essu#e an% "acili$a$es $e in"lu* o" 0a$e#. Os,o$ic cell in-u#esul$in+ "#o, i+ in$#acellula# so#)i$ol concen$#a$ions is one o" $e ,ecanis,s "o#%e'elo!,en$ o" co,!lica$ions o" %ia)e$es suc as neu#o!a$& an% #e$ino!a$&.A%%i$ionall& #e$en$ion o" 0a$e# in $e lens causes lens o!aci"ica$ion an% ca$a#ac$"o#,a$ion.Coice A3 Glucose is ,e$a)oli/e% in$o so#)i$ol )& al%ose #e%uc$ase. So#)i$ol in $u#nis con'e#$e% in$o "#uc$ose )& so#)i$ol %e&%#o+enase. Glucose is "o#,e% in cells )&$e !#ocesses o" +l&co+enol&sis an% +luconeo+enesis.Coices C an% D3 Ano$e# "unc$ion o" al%ose #e%uc$ase is con'e#sion o" +alac$osein$o +alac$i$ol i.e. $is en/&,e con'e#$s su+a#s in$o $ei# co##es!on%in+ su+a#alcools3. ?o#,all& $is !a$0a& is insi+ni"ican$. In +alac$ose,ia +alac$ose 14!os!a$e u#i%&l $#ans"e#ase %e"icienc&3 an inc#ease% a,oun$ o" +alac$i$ol is!#o%uce% #esul$in+ in ca$a#ac$ "o#,a$ion.Coice E3 &lulose is an en% !#o%uc$ o" +lucu#onic aci% ,e$a)olis, an% anin$e#,e%ia$e in $e !en$ose !os!a$e !a$0a&.


Al%ose #e%uc$ase con'e#$s +lucose in$o so#)i$ol 0ic is "u#$e# ,e$a)oli/e% in$o"#uc$ose )& so#)i$ol %e&%#o+enase. Tis !a$0a& is $e ,os$ ac$i'e in $e li'e# an%se,inal 'esicles.

217

Q NO 21:Ac$i'i$& o" an en/&,e calle% al%ose #e%uc$ase in $e lens o" a eal$&in%i'i%ual !#o%uces so#)i$ol $a$ can no$ e*i$ $e cells. Wic o" $e "ollo0in+ is$e ,os$ likel& !#o%uc$ o" so#)i$ol o*i%a$ion in $ese cells>


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A. Te#e a#e $0o ac$i'a$o# )in%in+ si$es "o# one ac$i'a$o# !#o$einB. Te#e a#e $0o o!e#a$o#s "o# one #e!#esso# !#o$einC. Te#e a#e $0o #e!#esso#s "o# one in%uce#D. Te#e a#e $0o !#o,o$e#s in close !#o*i,i$& $o eac o$e#E. Te#e is one ,R?A co%in+ "o# )o$ en/&,es

Explanation:

218

Q NO 22:E. coli colonies +#o0n on a lac$ose4con$ainin+ ,e%iu, u!4#e+ula$e $e!#o%uc$ion o" $e en/&,es 4+alac$osi%ase an% +alac$osi%e !e#,ease. Wic o"$e "ollo0in+ )es$ e*!lains $e s&nc#onous !#o%uc$ion o" )o$ en/&,es in#es!onse $o lac$ose>


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Te lac o!e#on is $e seuence o" $e E. coil +eno,e 0ic is #eui#e% "o# $e,e$a)olis, o" lac$ose. Te lac o!e#on consis$s o" a #e+ula$o#& +ene I3 !#o,o$e##e+ion !3 o!e#a$o# #e+ion o3 an% $#ee s$#uc$u#al +enes / & an% a3. Te / +eneco%es "o# 4+alac$osi%ase 4+al3 0ic is !#i,a#il& #es!onsi)le "o# $e &%#ol&sis o"lac$ose $o +lucose an% +alac$ose. Te & +ene co%es "o# !e#,ease a $#ans,e,)#aneen/&,e $a$ inc#eases $e !e#,ea)ili$& o" $e cell $o lac$ose. Te +ene enco%es a 4+alac$osi%e $#ansace$&lase 0ic $#ans"e#s ace$&l +#ou!s $o 4+alac$osi%es an% isunnecessa#& "o# lac$ose ,e$a)olis, )& E. coil.In !#oka#&o$es one ,R?A $#ansc#i!$ con$ains $e seuences "o# ,an& !#o$eins an%a sin+le ,R?A ,olecule can )e $#ansla$e% in$o ,ul$i!le !#o$eins o# !ol&!e!$i%es. (o#ins$ance all $#ee !#o$eins o" $e lac o!e#on 4+alac$osi%ase !e#,ease an%$#ansace$&lase3 a#e s&n$esi/e% "#o, a sin+le ,R?A ,olecule con$ainin+ $e / &an% a +ene seuences #es!ec$i'el&. T#ansc#i!$ion an% $#ansla$ion o" $e +enes o" $elac o!e#on is $&!icall& s&nc#onous. Re,e,)e# $a$ a sin+le ,R?A ,olecule 0icco%es "o# ,o#e $an one !#o$ein is #e"e##e% $o as a !ol&cis$#onic ,R?A an% 0ile,os$ !#oka#&o$ic ,R?A ,olecules a#e !ol&cis$#onic euka#&o$ic ,R?A is #a#el&!ol&cis$#onic.

Coices AD3 Te lac o!e#on 0ic co%es "o# all $#ee a"o#e,en$ione% !#o$eins is#e+ula$e% )& a sin+le o!e#a$o# a !#o,o$e# an% a sin+le +#ou! o" #e+ula$o#&ele,en$s8 an in%uce# #e!#esso# an% ca$a)oli$e ac$i'a$o# !#o$ein. Mo%ula$ion o" $e$#ansc#i!$ion o" $is o!e#on $#ou+ )in%in+ o" $e o!e#a$o# an% ac$ion o" $e#e!#esso# o# o$e# #e+ula$o#& ele,en$s 0ill can+e $e $#ansc#i!$ion o" all $#ee lac4o!e#on s$#uc$u#al +enes / & an% a3. On $e o$e# an% $e#e a#e no o!e#a$o#s#e!#esso#s o# in%uce#s $a$ can %es&nc#oni/e $e $#ansc#i!$ion o" lac4o!e#ons$#uc$u#al +enes.

E%uca$ional O)-ec$i'e8Bac$e#ial ,R?A can )e !ol&cis$#onic ,eanin+ $a$ one ,R?A co%es "o# se'e#al!#o$eins. An e*a,!le o" !ol&cis$#onic ,R?A is $e )ac$e#ial lac o!e#on 0ic co%es"o# $e !#o$eins necessa#& "o# lac$ose ,e$a)olis, )& E. coil $e $#ansc#i!$ion an%$#ansla$ion o" $ese )ac$e#ial !#o$eins is #e+ula$e% )& a sin+le !#o,o$e# o!e#a$o#an% se$ o" #e+ula$o#& ele,en$s.

219


36/85


A.

Ene#+&4in%e!en%en$ D?A un0in%in+B. Mul$i!le o#i+ins o" #e!lica$ionC. ?o R?A !#i,e#s s&n$esi/e% %u#in+ #e!lica$ionD. Con$inuous s&n$esis o" $e la++in+ s$#an%E. ?o !#oo"#ea%in+ )& D?A !ol&,e#ase !ol J3

Explanation:Te !#ocess o" D?A #e!lica$ion is si,ila# in euka#&o$es an% !#oka#&o$es. Te ke&s$e!s in'ol'e% in D?A #e!lica$ion a#e81. Un0in%in+ o" %ou)le s$#an%e% D?A %sD?A3 )& elicase $o !#o%uce sin+les$#an%e% D?A ssD?A3@. (o#,a$ion o" a #e!lica$ion "o#k9. (o#,a$ion o" an R?A !#i,e# )& $e ac$ion o" $e en/&,e !#i,ase:. S&n$esis an% concu##en$ !#oo"#ea%in+ o" %au+$e# D?A s$#an%s )& D?A!ol&,e#ases7. Li+a$ion o" Oka/aki "#a+,en$s on la++in+ s$#an%s )& li+ase an% #e,o'al an%

#e!lace,en$ o" R?A !#i,e#s 0i$ D?A )& D?A !ol&,e#ase I5. Recons$i$u$ion o" c#o,a$in an% li+a$ion o" %au+$e# s$#an%sIn E. coil a !#oka#&o$e $e $#ee ,a-o# $&!es o" D?A !ol&,e#ase a#e D?A!ol&,e#ase I II an% III. In euka#&o$es $e#e a#e "i'e ,a-o# D?A !ol&,e#ases8

220

Q NO 23:Te D?A #e!lica$ion !#ocess in euka#&o$ic cells closel& ,i,ics $a$ in!#oka#&o$ic cells )u$ $e 'olu,e o" +ene$ic ,a$e#ial $o )e #e!lica$e% is $&!icall&,uc +#ea$e# in euka#&o$ic cells. Wic o" $e "ollo0in+ ensu#es "as$ D?A#e!lica$ion in euka#&o$ic cells>


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al!a )e$a +a,,a %el$a an% e!silon. Tou+ $e euka#&o$ic +eno,e is ,ucla#+e# an% ,o#e co,!le* $an $e !#oka#&o$ic +eno,e in$e#es$in+l& $e si/e o" $eeuka#&o$ic +eno,e is no$ $e sou#ce o" i$s co,!le*i$&. I$s co,!le*i$& #esul$s "#o,$e !#esence o" a la#+e nu,)e# o" non4co%in+ D?A #e+ions )e$0een co%in+ #e+ions.Wi$in +enes $e#e a#e in$#ons ?on4co%in+ #e+ions 4 Tink ;I?< )e$0een3 se!a#a$in+e*ons Co%in+ #e+ions 4 Tink ;E< !#esse%3. P#oka#&o$es #a#el& a'e in$#ons 0i$in$ei# +enes.In con$#as$ $o !#oka#&o$es 0ic $&!icall& a'e a sin+le o#i+in o" #e!lica$ioneuka#&o$es a'e ,ul$i!le o#i+ins o" #e!lica$ion> Wi$ ,ul$i!le o#i+ins o" #e!lica$ion$e +eno,e can )e co!ie% ,uc ,o#e uickl& )ecause ,ul$i!le #e+ions a#e )ein+#e!lica$e% a$ once.Coices A C D an% E3 Te !#ocesses o" un0in%in+ s&n$esis o" an R?A !#i,e#s&n$esis o" lea%in+ an% la++in+ s$#an%s an% $e !#oo"#ea%in+ ac$i'i$& o" D?A!ol&,e#ases a#e si,ila# in !#oka#&o$es an% euka#&o$es.

E%uca$ional O)-ec$i'e8Mul$i!le o#i+ins o" #e!lica$ion ,ake euka#&o$ic D?A s&n$esis uick an% e""ec$i'e

%es!i$e $e la#+e si/e o" $e +eno,e co,!a#e% $o $a$ o" !#oka#&o$ic o#+anis,s.

221


38/85


A.

Pu'a$e kinaseB. Lac$a$e %e&%#o+enaseC. Pu'a$e %e&%#o+enaseD. Pu'a$e ca#)o*&laseE. Enolase

Explanation:

Te !a$ien$ %esc#i)e% in $e 'i+ne$$e as lac$ic aci%osis secon%a#& $o &!o!e#"usiono" is $issues an% su)seuen$ ,e$a)olis, o" +lucose 'ia anae#o)ic +l&col&sis. In $e!#ocess o" +l&col&sis +lucose is ul$i,a$el& con'e#$e% $o !u'a$e. Gl&col&sis $akes!lace in $e c&$osol an% o*i%a$i'e !os!o#&la$ion 0ic #eui#es $e !#esence o"o*&+en occu#s in $e ,i$ocon%#ia. Te "a$e o" !u'a$e +ene#a$e% %u#in+ +l&col&sisis %e!en%en$ on $e !#esence o" o*&+en. Wen ina%eua$e a,oun$s o" o*&+en a#e!#esen$ in $e $issues. !u'a$e is con'e#$e% $o lac$a$e )& $e en/&,e lac$a$e%e&%#o+enase in o#%e# $o #e+ene#a$e $e ?AD "#o, ?ADH H$ Tus un%e# anae#o)iccon%i$ions inc#ease% a,oun$s o" lac$a$e a#e +ene#a$e% )ecause !u'a$e is

222

Q NO 24:A 5:4&ea#4ol% ,ale os!i$ali/e% 0i$ se'e#e a)%o,inal !ain an%&!o$ension )e+ins $o &!e#'en$ila$e. La)o#a$o#& $es$in+ #e'eals ,e$a)olicaci%osis an inc#ease% anion +a! an% a i+ !las,a lac$a$e le'el. Tis!a$ien$=s "in%in+s a#e )es$ e*!laine% )& a lo0 ac$i'i$& o"8


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!#e"e#en$iall& con'e#$e% $o lac$a$e )& $e en/&,e lac$a$e %e&%#o+enase. Inc#ease%lac$a$e le'els #esul$ in ,e$a)olic aci%osis an% !a$ien$s 0i$ ,e$a)olic aci%osis 0illa$$e,!$ $o co,!ensa$e )& causin+ a #es!i#a$o#& alkalosis. Tis is acco,!lise% )&&!e#'en$ila$ion an% loss o" CO@ an aci% 0en %issol'e% in $e )loo%3. In $e!#esence o" o*&+en !u'a$e is !#e"e#en$iall& con'e#$e% $o ace$&l coen/&,e A )&$e en/&,e !u'a$e %e&%#o+enase coice C3. Ace$&l coen/&,e A en$e#s $e,i$ocon%#ia an% un%e#+oes o*i%a$i'e !os!o#&la$ion in $e ci$#ic aci% c&cle.Coice A3 Te "inal s$e! o" +l&col&sis is con'e#sion o" !os!oenol!u'a$e $o!u'a$e )& $e en/&,e !u'a$e kinase.Coice B3 Lac$a$e %e&%#o+enase is a )i%i#ec$ional en/&,e se#'es $o in$e#con'e#$!u'a$e an% lac$a$e. Tis en/&,e con'e#$s !u'a$e $o lac$a$e in anae#o)iccon%i$ions ,os$ classicall& in e*e#cisin+ skele$al ,uscle. I$ also !la&s a ke& #ole in$e li'e# 0e#e lac$a$e usuall& +ene#a$e% )& 0o#kin+ skele$al ,uscles is $aken u!"#o, $e )loo% an% con'e#$e% $o !u'a$e "o# +luconeo+enesis.Coice D3 Pu'a$e can also )e con'e#$e% $o o*aloace$a$e )& $e en/&,e !u'a$eca#)o*&lase. Tis en/&,e is in'ol'e% in #e+ene#a$ion o" +lucose "#o, !u'a$e )&$e !#ocess o" +luconeo+enesis.

Coice E3 Con'e#sion o" @4!os!o+l&ce#a$e$o !os!oenol!u'a$e isacco,!lise% )& $e en/&,e enolase.

E%uca$ional O)-ec$i'e8H&!o*ia4in%uce% lac$ic aci%osis is cause% )& a lo0 ac$i'i$& o" !u'a$e%e&%#o+enase o*i%a$i'e !os!o#&la$ion !a$0a&3 an% a i+ ac$i'i$& o" lac$a$e%e&%#o+enase.

223


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A. H)A1CB. H)SC. H)CD. H)(E. H)H

Explanation:

@ 94DPG is s&n$esi/e% as an in$e#,e%ia$e o" $e +l&col&$ic !a$0a& in $issues an%is an i,!o#$an$ #e+ula$o# o" o*&+en )in%in+ $o e,o+lo)in. I$ )in%s e,o+lo)in in a!ocke$ "o#,e% )& $e $0o )e$a cains see %ia+#a,3. Tis !ocke$ con$ains !osi$i'el&ca#+e% a,ino aci%s $a$ )in% $o $e ne+a$i'el&4ca#+e% !os!a$e a$o,s in @ 9DPG #esul$in+ in ionic )on%s connec$in+ eac o" $e )e$a e,o+lo)in su)uni$s $o @94DPG. @ 94DPG onl& )in%s $o %eo*&e,o+lo)in i$ %oes no$ )in% $o o*&e,o+lo)in.(e$al e,o+lo)in H)(3 is s&n$esi/e% %u#in+ "e$al %e'elo!,en$. I$ consis$s o" $eusual $0o al!a cains an% $0o +a,,a cains in !lace o" )e$a cains. Wi$in a "e00eeks o" conce!$ion $e "e$al li'e# )e+ins $o "o#, "e$al e,o+lo)in. A)ou$ 5O o"$e e,o+lo)in ci#cula$in+ %u#in+ $e las$ "e0 ,on$s in u$e#o an% $e "i#s$ "e00eeks o" !os$na$al li"e in an in"an$ is H)(. Te a""ini$& o" H)( Coice D3 $o o*&+en is

,uc i+e# $an $a$ o" H)A )ecause H)( %oes no$ )in% e""ec$i'el& $o @ 94DPG.Tis al$e#e% a""ini$& is %ue $o $e !#esence o" se#ine ins$ea% o" ca#+e% is$i%ine#esi%ues a$ $e no#,al @ 94DPG )in%in+ si$e. (e$al e,o+lo)in nee%s $o )in% ,o#e

224

Q NO 25:A sin+le a,ino aci% #esi%ue #e!lace,en$ se#ine ins$ea% o" is$i%ine3 in$e e,o+lo)in 4su)uni$ #esul$s in !oo# ionic in$e#ac$ion 0i$ @.94)i!os!o+l&ce#a$e. Te #esul$an$ e,o+lo)in as $e !#o!e#$ies o" 0ic o" $e"ollo0in+>


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a'i%l& $an a%ul$ e,o+lo)in )ecause $e "e$al e,o+lo)in ,us$ o)$ain o*&+en "#o,$e ,o$e#=s a%ul$ e,o+lo)in in $e !lacen$a.Coice A3 H)Alc is "o#,e% )& non4en/&,a$ic +l&cos&la$ion a$$ac,en$ o" +lucose3o" H)A. In non%ia)e$ic in%i'i%uals a!!#o*i,a$el&:45 o" e,o+lo)in is +l&cos&la$e%0ile in !a$ien$s 0i$ uncon$#olle% %ia)e$es $e !e#cen$a+e o" +l&cos&la$e%e,o+lo)in is ,uc i+e#. H)Alc is use% clinicall& $o assess o'e#all )loo% su+a#con$#ol "o# $e $#ee ,on$s !#ece%in+ $e $es$. Gl&cos&la$e% e,o+lo)in %oes no$al$e# $e )in%in+ o" e,o+lo)in $o @94 DPG.Coice B3 H)S is $e !#e%o,inan$ "o#, o" e,o+lo)in in sickle cell %isease. A,olecule o" H)S con$ains $0o no#,al al!a cains an% $0o ,u$a$e% )e$a +lo)incains ca#ac$e#i/e% )& #e!lace,en$ o" +lu$a,a$e a$ !osi$ion si* )& 'aline.Coice C3 H)C #esul$s "#o, a ,u$a$ion in $e )e$a +lo)in cain causin+ +lu$a,icaci% $o )e #e!lace% )& l&sine. Tese !a$ien$s a'e ,il% c#onic e,ol&$ic ane,ia.Coice E3 A %e"ec$ in $e s&n$esis o" al!a cains #esul$s in al!a $alasse,ia.?o#,al in%i'i%uals a'e "ou# co!ies o" $e al!a +ene so se'e#al le'els o" al!a4+lo)in %e"ec$s can occu#.

E%uca$ional O)-ec$i'e8?o#,all& @ 94DPG "o#,s ionic )on%s 0i$ $e $0o )e$a su)uni$s o" H)A in $e$issues a"$e# e,o+lo)in as )een %eo*&+ena$e%. (e$al e,o+lo)in )in%s o*&+en0i$ a i+e# a""ini$& %ue $o i$s ina)ili$& $o in$e#ac$ 0i$ @ 94 DPG. Ul$i,a$el& $e"e$al e,o+lo)in ,us$ )e a)le $o e*$#ac$ 6@ "#o, ,a$e#nal e,o+lo)in in $e!lacen$a.

225


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A. GlucoseB. (#uc$ose454!os!a$eC. Lac$a$eD. Pu'a$eE. Ci$#a$e(. Mala$eG. (u,a#a$eH. ATP

226

Q NO 26:A +#ou! o" in'es$i+a$o#s %isco'e#s a !o$assiu, cannel a)no#,ali$& "oun%in !anc#ea$ic )e$a cells. Tis a)no#,ali$& causes &!o+l&ce,ia )ecause i$ ,akes $e!o$assiu, cannels i+l& sensi$i'e $o $ei# no#,al ac$i'i$&4,o%ula$in+ #e+ula$o#&su)s$ance. Wic o" $e "ollo0in+ #e+ula$o#& su)s$ances is ,os$ likel& i,!lica$e% in$is case>


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Explanation:

Te #e+ula$ion o" insulin sec#e$ion "#o, !anc#ea$ic )e$a cell is a co,!le* !#ocess.Glucose is $e ,os$ i,!o#$an$ s$i,ula$o# o" insulin #elease. Glucose en$e#s )e$a cells)& "acili$a$e% %i""usion usin+ +lucose $#ans!o#$e# @ GLUT @3 Glucose a"$e# en$e#in+)e$a cells un%e#+oes seuen$ial o*i%a$i'e ,e$a)olis, $#ou+ +l&col&sis "ollo0e% )&$e ci$#ic aci% c&cle 0ic +ene#a$es ATP. A i+ ATP $o ADP #a$io 0i$in )e$a cellscauses $e closu#e o" !o$assiu, 2ATP3 cannels. Tis closu#e occu#s 0en ATP)in%s $o $e #e+ula$o#& su)uni$ o" $e 2ATP cannel. 2ATP cannels a#e #es!onsi)le"o# $e ou$0a#% ,o'e,en$ o" !o$assiu, "#o, $e )e$a cells. Wen $ese cannelsclose )e$a cells %e!ola#i/e 0ic #esul$s in $e o!enin+ o" 'ol$a+e4%e!en%en$calciu, cannels. Hi+ in$#acellula# calciu, $en lea%s $o insulin #elease. De"ec$s o"$e 2ATP cannel +ene can #esul$ in $&!e $0o %ia)e$es. Te %e"ec$ causes e*cess"unc$ion o" $is RATP cannel $e cannels %o no$ close )e$a cells "ail $o )e%e!ola#i/e% an% $e#e is an ina%eua$e insulin #es!onse $o +lucose. Sul"on&lu#easa#e ;an$i%ia)e$ic< ,e%ica$ions $a$ a#e $aken o#all&$e& 0o#k )& %i#ec$l& )in%in+ $o$e #e+ula$o#& su)uni$s o" 2ATP cannels causin+ $e, $o close.Coices B C an% D3 (#uc$ose 54!os!a$e !u'a$e an% lac$a$e a#e in$e#,e%ia$e

!#o%uc$s o" $e +l&col&$ic !a$0a&. Lac$a$e is !#o%uce% )& anae#o)ic +l&col&sis. Be$acells a'e a #ic o*&+en su!!l& an% ,os$ o" $e +l&col&sis $a$ occu#s in )e$a cells isae#o)ic. Tus a 'e#& s,all a,oun$ o" lac$a$e is !#o%uce%. Pu'a$e is con'e#$e% in$oace$&l co4en/&,e A 0ic en$e#s $e ,i$ocon%#ia "o# ,e$a)olis, 'ia $e ci$#ic aci%c&cle.Coices E ( an% G3 Ci$#a$e ,ala$e an% "u,a#a$e a#e in$e#,e%ia$es in $e ci$#ic aci%c&cle. Du#in+ $is !#ocess ene#+& is s$o#e% as ?ADH an% (ADH@. ATP is $en!#o%uce% 0en ?ADH an% (ADH@ en$e# o*i%a$i'e !os!o#&la$ion. Te !#o%uc$s an%in$e#,e%ia$es o" +l&col&sis an% $e ci$#ic aci% c&cle lis$e% in $ese coices %o no$a'e an& %i#ec$ e""ec$ on 2ATP cannels.

E%uca$ional O)-ec$i'e8ATP is $e #e+ula$o#& su)s$ance $a$ s$i,ula$es 2ATP cannel closu#e in insulin4!#o%ucin+ !anc#ea$ic )e$a cells.

227


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A.L&sineB. P#olineC. AlanineD. Gl&cineE. Leucine(. C&s$eine

Explanation:

Colla+en is $e ,os$ a)un%an$ !#o$ein in $e u,an )o%&. Te colla+en ,oleculeconsis$s o" $#ee !ol&!e!$i%e al!a cains el% $o+e$e# )& &%#o+en )on%s $o "o#,a #o!e4like $#i!le eli*. Colla+en is s&n$esi/e% in "i)#o)las$s os$eo)las$s an%con%#o)las$s. Te colla+en ,olecule as a $#i!le elical con"o#,a$ion )ecause eaco" $e al!a cains as a si,!le #e!e$i$i'e a,ino aci% seuence in 0ic +l&cineGl&3 a!!ea#s a$ e'e#& $i#% a,ino aci% !osi$ion. Te a,ino aci% seuence o"

colla+en is $e#e"o#e %esi+na$e% 4Gl&44Y43 999. To "ol% in$o a $#i!le eli* e'e#&$i#% a,ino aci% in eac al!a cain ,us$ )e +l&cine. Gl&cine is $e s,alles$ a,inoaci% an% i$ "i$s in$o $e #es$#ic$e% s!ace $a$ e*is$s 0en $#ee al!a cains co,e$o+e$e# $o "o#, a $#i!le eli*.Man& o" $e a,ino aci%s %esi+na$e% an% Y a#e !#oline #esi%ues. P#oline is essen$ial"o# $e "o#,a$ion o" $e al!a eli* )ecause i$s #in+ s$#uc$u#e in$#o%uces a )en% in$o$e !ol&!e!$i%e cains. O$e# an% Y a,ino aci%s "o#, clus$e#s o" &%#o!o)ic an%ca#+e% #e+ions on $e su#"ace o" $e ,olecule $a$ ena)les c#oss linkin+ $o o$e#colla+en ,olecules. L&sine is co,,onl& use% in colla+en "o# $is !u#!ose.

E%uca$ional O)-ec$i'e8Gl&cine is $e ,os$ a)un%an$ a,ino aci% in $e colla+en ,olecule. I$ occu#s in ATLEAST e'e#& $i#% a,ino aci% !osi$ion. Te a,ino aci% "o#,ula o" colla+en is 4Gl&44Y43 999.

228

Q NO 27:Skin "i)#o)las$s incu)a$e% 0i$ #a%ioac$i'e a,ino aci%s s&n$esi/e!ol&!e!$i%e cains $a$ asse,)le $o "o#, a $#i!le eli*. Wic o" $e"ollo0in+ a,ino aci%s is ,os$ a'i%l& consu,e% )& $e "i)#o)las$s>


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A. Pen&lalanineB. alineC. As!a#a+ineD. His$i%ineE. P#oline(. L&sine

Explanation:

Ca$a)olis, o" isoleucine 'aline $#eonine ,e$ionine coles$e#ol an% o%%4cain"a$$& aci%s lea%s $o $e "o#,a$ion o" !#o!ionic aci% 0ic is $en con'e#$e% $o,e$&l,alonic aci% )& )io$in4%e!en%en$ ca#)o*&la$ion. Iso,e#i/a$ion o",e$&l,alon&l CoA "o#,s succin&l CoA 0ic $en en$e#s $e TCA c&cle. Acon+eni$al %e"icienc& o" !#o!ion&l CoA ca#)o*&lase $e en/&,e #es!onsi)le "o# $e

con'e#sion o" !#o!ion&l CoA $o ,e$&l,alon&l CoA lea%s $o $e %e'elo!,en$ o"!#o!ionic aci%e,ia as !#o!ion&l CoA accu,ula$es. P#o!ionic aci%e,ia is clinicall&ca#ac$e#i/e% )& !oo# "ee%in+ 'o,i$in+ &!o$onia le$a#+& %e&%#a$ion an% an

229

Q NO 28:A ne0)o#n e*!e#iences le$a#+& 'o,i$in+ an% &!o$onia %u#in+ $e "i#s$"e0 %a&s o" li"e. La)o#a$o#& e*a,ina$ion #e'eals a ,e$a)olic aci%osis 0i$ a la#+eanion +a! ke$osis an% &!o+l&ce,ia. Te concen$#a$ion o" !#o!ionic aci% is,a#ke%l& inc#ease% in $e !las,a an% u#ine. Me$a)olis, o" 0ic o" $e "ollo0in+a,ino aci%s con$#i)u$es $o $is !a$ien$=s con%i$ion>


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anion +a! aci%osis. P#o!ionic aci% is $e in$e#,e%ia$e in $e ca$a)olis, o" )#ance%cain a,ino aci%s suc as 'aline an% is no$ !#o%uce% %u#in+ $e ca$a)olis, o" $eo$e# a,ino aci%s lis$e%.Coice A3 Pen&lalanine is con'e#$e% $o $osine )& $e en/&,e !en&lalanine&%#o*&lase 0ic is %e"ec$i'e in !en&lke$onu#ia PRU3.Coice C3 As!a#a+ine is a nonessen$ial a,ino aci% $a$ is ca$a)oli/e% ini$iall& $oas!a#$a$e )& $e en/&,e as!a#a+inase. In #a!i%l& %i'i%in+ leuke,ic cells $es&n$esis o" as!a#a+ine is i,!ai#e% so $ese cells su#'i'e )& collec$in+ as!a#a+ine"#o, ci#cula$in+ !las,a. L4as!a#a+inase 0o#ks as an an$ineo!las$ic a+en$ )&lo0e#in+ ci#cula$in+ as!a#a+ine le'els.Coice D3 His$i%ine is an essen$ial a,ino aci% in cil%#en. His$i%ine is %ea,ina$e% $ou#ocanic aci% 0ic is $en con'e#$e% $o ?4"o#,inino4+lu$a,a$e (IGIu3. Te"o#,inino +#ou! o" (IGIu is %ona$e% $o $e$#a&%#o"ola$e $o "o#, +lu$a,a$e an%"o#,inino4$e$#a&%#o"ola$e. O*i%a$i'e %eca#)o*&la$ion o" is$i%ine "o#,s is$a,ine0ic is #elease% )& ,as$ cells in T&!e I H&!e#sensi$i'i$& #eac$ions.Coice E3 P#oline is a nonessen$ial a,ino aci% $a$ is o*i%i/e% $o +lu$a,a$e 0icin $u#n is $#ansa,ina$e% $o al!a ke$o+lu$a#a$e.

Coice (3 L&sine is an essen$ial a,ino aci% $a$ is s$#ic$l& ke$o+enic. Te,e$a)olis, o" l&sine is uniue co,!a#e% 0i$ $e o$e# a,ino aci%s as i$ is no$$#ansa,ina$e% as an ini$ial s$e!.

E%uca$ional O)-ec$i'e8P#o!ion&l CoA is %e#i'e% "#o, a,ino aci%s al lie Me$ an% T#3 o%%4nu,)e#e%"a$$& aci%s an% coles$e#ol si%e cains. Con+eni$al %e"icienc& o" !#o!ion&l CoAca#)o*&lase $e en/&,e #es!onsi)le "o# $e con'e#sion o" !#o!ion&lCoA $o ,e$&l,alon&l CoA lea%s $o $e %e'elo!,en$ o" !#o!ionic aci%e,ia.

230


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A.cAMPB. Ca@QC. ClD. ?OE. ,R?A(. cGMP

Explanation:A 'a#ie$& o" o#,ones a#e kno0n $o e*e#$ $ei# in$#acellula# e""ec$s 'ia $e 1P9secon% ,essen+e# s&s$e,. A "e0 o" $ese o#,ones an% #ece!$o#s inclu%e al!a4ia%#ene#+ic #ece!$o#s o*&$ocin $e 'ascula# #ece!$o# "o# 'aso!#essin an+io$ensin II+#o0$ o#,one #eleasin+ o#,one $oi% #eleasin+ o#,one an% +ona%o$#o!in#eleasin+ o#,one. Te IP9 secon% ,essen+e# s&s$e, )e+ins 0i$ $e )in%in+ o"o#,one $o i$s cell su#"ace #ece!$o#. Tis )in%in+ causes $e e*can+e o" GDP "o#GTP on $e al!a su)uni$ o" $e G4!#o$ein associa$e% 0i$ $is #ece!$o#. Teac$i'a$e% al!a su)uni$ un%e#+oes a con"o#,a$ional can+e an% e*!oses a!os!oli!ase C ac$i'a$in+ ca$al&$ic si$e. Pos!oli!ase C is $en ac$i'a$e%.Pos!oli!ase C %e+#a%es !os!oli!i%s $o %iac&l+l&ce#ol an% inosi$ol $#i!os!a$e1P93. Diac&l+l&ce#ol is a)le $o %i#ec$l& s$i,ula$e !#o$ein kinase C )u$ $e ,a-o#ac$i'a$o# o" !#o$ein kinase C in $is !a$0a& is $e inc#ease% in$#acellula# calciu,$a$ occu#s 0en IP9 causes #elease o" in$#acellula# calciu, s$o#es "#o, $e

231

Q NO 29:An a+en$ a!!lie% $o u,an cells is )elie'e% $o ac$i'a$e G4!#o$ein%e!en%en$ !os!oli!ase C. Wic o" $e "ollo0in+ in$#acellula# su)s$ancesis ,os$ likel& $o inc#ease i,,e%ia$el& a"$e# e*!osu#e $o $is a+en$.


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en%o!las,ic #e$iculu, in$o $e c&$osol. P#o$ein kinase C is $e ,a-o# a""ec$o#,olecule in $is !a$0a& in $a$ is %i#ec$l& ,o%ula$e% $e ac$i'i$& o" $e en/&,es#e+ula$e% )& $e o#,one.Coices A an% (3 In$#acellula# cAMP an% cGMP concen$#a$ions occu# %u#in+ac$i'a$ion o" $e G4!#o$ein a%en&la$e c&clase o# G4!#o$ein F +uan&la$e c&clasesecon% ,essen+e# s&s$e,s o# in s$a$es 0e#e s!eci"ic !os!o%ies$e#ases a#eini)i$e% as can )e seen u!on e*!osu#e $o !os!o%ies$e#ase ini)i$o#s suc as $e*an$ine class o" %#u+s an% in $e ac$ion o" sil%ena"il 0ic selec$i'el& ini)i$s cGMP!os!o%ies$e#ase.Coice C3 Te in$#acellula# clo#i%e C#3 concen$#a$ion inc#eases in s$a$es o"neu#onal ini)i$ion )& &!e#!ola#i/a$ion a"$e# ini)i$o#& neu#o$#ans,i$$e#s suc asGABA o# +l&cine ac$ on $e neu#on an% inc#ease Cl4 con%uc$ance.Coice D3 In$#acellula# ni$#ic o*i%e ?O en%o$eliu,4%e#i'e% #ela*in+ "ac$o#3 isinc#ease% in s$a$es 0e#e 'aso%ila$a$ion is %esi#e% )& $e )o%& an% also in $e!#o%uc$ion o" a !enile e#ec$ion. ?O is s&n$esi/e% "#o, a#+inine an% o*&+en )& $een/&,e ni$#ic o*i%e s&n$ase.Coice E3 Te in$#acellula# concen$#a$ion o" ,R?A inc#eases %u#in+ i+ cellula#

s$a$es o" !#o$ein s&n$esis suc as %u#in+ %i'ision.

E%uca$ional O)-ec$i'e8Te IP9 secon% ,essen+e# s&s$e, )e+ins 0i$ o#,one )in%in+ an% G4!#o$einac$i'a$ion lea%in+ $o ac$i'a$ion o" !os!oli!ase C. Pos!oli!ase C "o#,s%iac&l+l&ce#ol an% IP9 "#o, !os!oli!i%s an% IP9 causes an inc#ease in in$#acellula#calciu, 0ic $en ac$i'a$es !#o$ein kinase C.

232


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A. S!ec$#inB. ?aF2 ATPaseC. Ca#)onic an&%#aseD. @ 94)i!os!o+l&ce#a$e ,u$aseE. Glucoso454!os!a$e %e&%#o+enase

Explanation:

He,o+lo)in is onl& "oun% 0i$in #e% )loo% cells RBCs3 an% is #es!onsi)le no$ onl&"o# o*&+en %eli'e#& $o $e $issues )u$ also "o# ca##&in+ ca#)on %io*i%e "#o, $e$issues $o $e lun+s. He,o+lo)in ca##ies ca#)on %io*i%e as ca#)a,a$e 0ic is"o#,e% as "ollo0s8

CO@ Q H)4?H9 @HQ Q H)4?H4CO@

He,o+lo)in is #es!onsi)le "o# ca##&in+ l7 o" ca#)on %io*i%e as ca#)a,a$e an% $e#e,ain%e# o" ca#)on %io*i%e is ca##ie% as )ica#)ona$e ion 0i$in $e #e% )loo% cells.Ca#)on %io*i%e !#o%uce% )& $issue #es!i#a$ion en$e#s #e% )loo% cells an% is &%#a$e%)& ca#)onic an&%#ase $o "o#, ca#)onic aci%. Ca#)onic aci% $en un%e#+oess!on$aneous con'e#sion $o HC69 a% H$ Man& o" $e )ica#)ona$e ions %i""use ou$ o"$e RBC in$o $e !las,a. To ,ain$ain $e elec$#ical neu$#ali$& clo#i%e ions %i""usein$o $e REC $o $ake $ei# !lace. Tis !#ocess is calle% ;clo#i%e si"$< an% i$ is $e!#inci!al cause o" i+ REC clo#i%e con$en$ in 'enous )loo%.Coice A3 S!ec$#in is a s$#uc$u#al co,!onen$ o" $e ,e,)#ane o" RBC7 $a$ +i'es$e cells "le*i)ili$&. A)no#,ali$ies o" s!ec$#in #esul$ in a)no#,al #e% )loo% cell sa!e

an% susce!$i)ili$& $o e,ol&sis.Coice B3 ?aQF2Q4ATPase is an i,!o#$an$ ion !u,! #es!onsi)le "o# $e,ain$enance o" ionic concen$#a$ion +#a%ien$s ac#oss $e !las,a ,e,)#ane. Tisene#+&4#eui#in+ !u,! is elec$#o+enic in na$u#e )ecause i$ e*$#u%es $#ee so%iu,

233

Q NO 30:I$ as )een %e$e#,ine% in eal$& 'olun$ee#s $a$ $e clo#i%e con$en$ o"e#&$#oc&$es is ,uc lo0e# in a#$e#ial )loo% $an in 'enous )loo%. Te ac$ion o"0ic a$ $e "ollo0in+ is ,os$l& #es!onsi)le "o# $e o)se#'e% %i""e#ence>


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ions "o# e'e#& $0o !o$assiu, ions $a$ en$e# $e cell 0ic c#ea$es ne+a$i'ein$#acellula# !o$en$ial. Tis !u,! is no$ #es!onsi)le "o# ,o'e,en$ o" clo#i%e ions.Coice D3 @ 94DPG is !#esen$ in s,all uan$i$ies in ,os$ cells o0e'e# ine#&$#oc&$es $e concen$#a$ion o" @ 94 DPG is i+. In $e RBCs @494DPG co,)ines0i$ e,o+lo)in an% %ec#eases i$s a""ini$& "o# o*&+en 0ic "acili$a$es o*&+en%eli'e#& $o $e $issue. @ 94DPG i$sel" is no$ #es!onsi)le "o# $e clo#i%e si"$.Coice E3 Clucose454!os!a$e %e&%#o+enase is $e "i#s$ en/&,e in $e !en$ose!os!a$e !a$0a&. Pa$ien$s 0i$ +lucose454!os!a$e %e&%#o+enase %e"icienc&!#esen$ 0i$ e!iso%ic e,ol&sis in%uce% )& o*i%an$ s$#esso#s.

E%uca$ion

Biochem 50q.doc

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