07/07/2016 Q. All of the following regarding isomerism in carbohydrates are true except: a. Ribose and ribulose are structural isomers of each other. . !"glucose and #"glucose are non"su$erim$osable mirror images of each other. %. d"glucose and l"glucose are non"su$erim$osable mirror images of each other oth er.. !. Anomers are e$imers at the first carbon of the monosaccharide. A. %. d"glucose and l"glucose are non"su$erim$osable mirror images of each other. Enantiomers are the non su$erim$osable mirror images of each other& which are re$resented by u$$ercase letters ! and #. lower case letters d and l stand for ability to rotate $lane of $olari'ed light in o$$osite directions ( de)trorotatory *d/+, or le-orotatory *l/",. n solution& glucose is de)trorotatory & hence called de)trose and fructose is le-orotatory. Anomer is a s$ecial ty$e of e$imer. Anomeric carbon is the carbon atom which becomes a chiral center after chain confirmation of a sugar is con-erted to its ring form. ith reference to anomeric carbon& there are two ty$e of isomers" al$ha * , and beta *, de$ending u$on the $osition of hydro)yl grou$.
Q. A 3 year old obese male $resented in the clinic with com$laints of increased urination& increased thirst &tingling in e)tremities and clouding of -ision. 4n com$lete e)amination& he was diagnosed to ha-e ty$e diabetes mellitus&with de-elo$ment of $olyneuro$athy and cataract in both eyes. hich of the following metabolite of glucose is res$onsible for the cataract in this $atient5 A. Amine deri-ati-e of glucose . Acidic deri-ati-e of glucose %. !eo)y deri-ati-e of glucose !. Alcohol deri-ati-e of glucose A. !. Alcohol deri-ati-e of glucose Reduction of glucose $roduces alcohol deri-ati-es orbitol& which is res$onsible for cataract formation in diabetes. 4ne of the theories of
$atho$hysiology $atho$hysiology e)$laining chronic com$lications com$lications of ! is increased sorbitol formation due to increased acti-ity of aldose reductase. orbitol increase changes redo) $otential and cellular osmolality& along with increased $roduction of free radicles& which lead to cataract and other com$lications.
Q. All of the following com$ounds com$ounds are e$imeric forms of each other except: A. Ribose . 8ylose %. Arabinose !. 8ylulose. A. !. 8ylulose 9$imers are com$ounds differing at one carbon atom 9)am$les are: mannose is an e$imer of glucose at %2 & galactose is an e$imer of glucose at %& alose is an e$imer of galactose at %2& Ribose has 2 e$imers"8ylose at %; < Arabinose at %2.
Q. enedict=s test done with the gi-en sam$le demonstrated the following results:
Rt"%ontrol> #t"est hich of the following carbohydrate would not be $resent in this sam$le5 A. glucose . fructose %. lactose !. trehalose A. !. trehalose
9)ce$t for sucrose and trahalose& the end of these sugars contain free anomeric carbon& called the reducing end. herefore& these two sugars can not $artici$ate in the o)idation"reduction reactions characteristic of reducing sugars*ie enedicts test,. he $rinci$le of enedict?s test is that when reducing sugars are heated in the $resence of an al@ali& they get con-erted to $owerful reducing com$ounds @nown as enediols. 9nediols reduce the cu$ric ions *%u2+, $resent in the enedict?s reagent to cu$rous ions *%u +, which get $reci$itated as insoluble red co$$er*, o)ide*%u24,.
Q. #actulose& a synthetic com$ound& is used in he$atic ence$halo$athy to reduce the intestinal absor$tion of ammonia. hich of the following o$tions correctly re$resent the com$osition of this com$ound5 A. lucose < galactose . serine < galactose %. fructose < galactose !. glycine < galactose A. %. fructose < galactose #actulose is a synthetic disaccharide com$osed of fructose < galactose& which is classified as a osmotic la)ati-e& and used in he$atic ence$halo$athy as it con-erts diffusible ammonia into ammonium ion which can not enter the systemic circulation.
Q. Brimary structure of both starch and glycogen are re$resented below:
ranches in the amylo$ectin unit in starch and glycogen are seen at residue: a. 10&2C b. 2C& 10 c. 0&20 d. 20& 0 A. a. 10&2C oth starch < glycogen are $olysaccharides of glucose lin@ed by a 1" glycosidic bond. oth the molecules contain two units : amylase"linear $olymer of glucose and amylo$ectin ( linear $olymer of glucose with few branch $oints * 1"6,. n starch & branches occur in these chains e-ery 12 to ;0 residues in amylo$ectin whereas in glycogen it occurs e-ery C to 12 residues.
Q. Dollowing is a re$resentation of al$ha granules& a storage form of glycogen in the li-er and muscle& which consists of around ;0&000 molecules of glucose.
hich molecule is $resent in the center of the granule5 A. REA $rimer . !EA $rimer %. #i$id $rimer !. Brotein $rimer
A. !. Brotein $rimer he center of granule contains a $rotein @nown as glycogenin& which acts a $rimer for glycogen synthesis.
Q. he following macromolecules in the body can not be synthesi'ed de no-o: A. !EA < lycogen . $hingoli$id < lycogen %. Bhos$holi$id < REA !. tarch < lycogen A. A. !EA < lycogen oth !EA < glycogen reFuire a $rimer for their synthesis ie an REA $rimer and a $rotein $rimer res$ecti-ely. Q. tructural homo$olysaccharide& chitin& which is an integral com$onent of e)os@eletal of insects is com$osed of : A. E"acetyl glucosamine*beta 1" lin@ages, . E"acetyl glucosamine*al$ha 1" lin@ages, %. E"acetyl galactosamine*beta 1" lin@ages, !. E"acetyl galactosamine*al$ha 1" lin@ages, A. A. E"acetyl glucosamine*beta 1" lin@ages, %hitin is a homo$olymer of E (acetyl glucosamine with 1" lin@ages found in cell wall of yeasts& e)os@eletal of insects < arthro$ods. t can be used to ma@e biodegradable surgical sutures. ncreased e)$osure to chitin eg in shellfish industry& increases #" le-els and $robability of de-elo$ing asthma. Q. %ellulose $resent in $lants ha-e no nutrition benefit because: A. t is not $resent in the diet in sufficient amounts. . lucose is Goined in al$ha glycosidic lin@ages&which cannot be bro@en by en'ymes. %. lucose is Goined in beta glycosidic lin@ages&which cannot be bro@en by en'ymes.
!. %ellulose is not $resent in the $lant food. A. %. lucose is Goined in beta glycosidic lin@ages&which cannot be bro@en by en'ymes. %ellulose is a homo$olymer of glucose with 1" lin@ages $resent in $lants. t can not be bro@en by the gi en'ymes because of beta lin@ages&and hence has no nutriti-e benefit.
Q. A $atient with sus$ected renal failure is ad-ised to undergo a test for the estimation of DR. hich of the following molecule can be used for the abo-e $ur$ose5 A. #actose . nulin %. lycogen !. %hitin A. . nulin nulin is a homo$olymer of fructose found in $lants and used to measure DR.
Q. All of the following are e)am$les of hetero$olysaccharides in nature except: A. A . Agar %. Bectin !. %hitin
A. !. %hitin Hetero$olysaccharides are $olysaccharides containing more than one ty$e of monosaccharide unit. hey include glycosaminoglycans*A or muco$olysaccharides, in humans& agar& gum < $ectin in $lants %hitin is a homo$olysaccharide of E (acetyl glucosamine.
Q. hich of the following muco$olysaccharide do not contain an acidic sugar5 A. !ermatan sulfate . Ieratan ulfate %. He$aran sulfate !. %hondroiton ulfate A. . Ieratan ulfate 4nly A to ha-e galactose in its structure instead of a acid sugar is Ieratan sulfate. I is res$onsible for balancing the hydration of cornea& hence maintains its trans$arency.
Q. he following A is de-oid of any sulfur grou$ in its structure: A. He$arin . Hyaluronic acid %. Ieratan sulfate !. !ermatan sulfate
A. . Hyaluronic acid 4nly A to be de-oid of sulfate grou$s is hyaluronic acid. HA is found in syno-ial tissue and forms stem cell niche.
Q. lycosaminglycans are hetero$olysaccharides& which assist in the $roduction of e)tracellular matri) e)ce$t: A. He$aran ulfate . He$arin %. Hyaluronic acid !. Ieratan sulfate A. . He$arin 4nly A to $resent intracellularly. t is stored in mast cells. t hel$s to retain histamine inside the -esicles electrostatically. Also& he$arin acts as an anticoagulant by binding to antithrombin and acti-ating it. his lysis thrombin and $re-ents clot formation.
Q. Broteoglycan& an integral $art of connecti-e tissues& contains ma)imum $ercentage of : A. Brotein . %arbohydrate %. #i$id !. Eucleic acids
A. . %arbohydrate Broteoglycans are large molecules made u$ of J0K carbohydrate*hetero$olysaccahride, and 10K $roteins*core $rotein < lin@er $rotein,.
Q. All of the following statements regarding $roteoglycans are true e)ce$t: A. Aggrecans is $resent in cartilages. . %ontains core $rotein and lin@er $rotein %. %an bind to water and cations !. %ontains more oligosaccharides than hetero$olysaccharides. A. !. %ontains more oligosaccharides than hetero$olysaccharides. Broteoglycans are large molecules made u$ of J0K carbohydrate*hetero$olysaccahride, and 10K $roteins*core $rotein < lin@er $rotein,. As it is rich in sulfate grou$s& it can bind water and cations. and control their mo-ement. 9)am$les are aggrecans $resent in cartilages& -ersican $resent in s@in < blood -essels.
Q. All of the following lysosomal storage diseases are associated with the accumulation of muco$olysaccharides in the lysosomes e)ce$t: A. Hurlers syndrome . Eiemann Bic@ syndrome %. Hunters yndrome !. an Dili$o syndrome A. . Eiemann Bic@ syndrome
Rest are muco$olysaccharidosis. Eiemann Bic@ syndrome is a s$hingoli$idosis.
Q. A ;year old child $resented with delay in de-elo$ment and following facial features.
4n e)amination& the child had corneal clouding& he$atos$lenomegaly& -acuolated lym$hocytes and inguinal hernia. hat can be the most $robable diagnosis in this child5 A. Eiemann"Bic@ syndrome . Hurlers yndrome %. Hunters syndrome !. auchers disease A. . Hurlers yndrome he child in $icture has flat nose& $rotruded forehead and macrognathia. All of these feature $oint towards the diagnosis of B " Hurlers syndrome& which occurs due to deficiency of iduronidase en'yme in the degradation of he$arin and dermatan sulfate.
Q. hich B out of the o$tions mentioned below will ha-e least clinical sym$toms5 A. B H . B %. B H"
!. B A. . B cheie syndrome is a subty$e of Hurlers syndrome with less clinical manifestations. Q. All of the following muco$olysaccharidosis *B, syndromes are autosomal recessi-e in inheritance e)ce$t: A. B H . B %. B H" !. B A. !. B All e)ce$t B & Hunters syndrome are autosomal recessi-e. Hunters syndrome is 8"lin@ed recessi-e in inheritance.
Q. A 2 year old child $resented with delay in de-elo$ment & $ebbly s@in and coarse facial features. 4n e)amination& the child had retinal degeneration& he$atos$lenomegaly& granulated neutro$hils and short stature. hat can be the most $robable diagnosis in this child5 A. Eiemann"Bic@ syndrome . Hurlers yndrome %. Hunters syndrome !. auchers disease
A. %. Hunters syndrome Hunters syndrome is B & which is 8"lin@ed in inheritance. t is characteri'ed by deficiency of iduronidase en'yme and e)cess accumulation of he$arin sulfate and dermatan sulfate.
Q. All of the following B syndromes ha-e a$$ro-ed en'yme re$lacement thera$ies e)ce$t: A. Hurlers yndrome . Hunters syndrome %. anDili$o yndrome !. aroteau)"#amy yndrome A. %. anDili$o yndrome All of the abo-e e)ce$t B has D!A a$$ro-ed en'yme re$lacement thera$y.
Q. identify the statement which best describes glucose : A. t is a %2 e$imer of mannose. . it is $resent in circulation as #"glucose. %. the ring formed by glucose is furanose ring. !. t contains @eto grou$ at the carbonyl carbon.
A. A. t is a %2 e$imer of mannose. annose is an e$imer of glucose at %2. he ring form of glucose is $yranose and for fructose it is furanose. All the carbohydrates e)ist in ! isomeric form and amino acid in the #"isomeric form. lucose is an aldose sugar&wherease fructose is an @eto sugar.
Q. hich of the following best describes the action of $ancreatic amylase in the digestion of carbohydrates5 A. 4$timal $H for its action is 2.3. . tarch is bro@en down to maltose and maltotriose. %. Dree glucose is $roduced as a result of its action. !. t also acts on disaccharides to $roduce constitutional monosaccharides. A. . tarch is bro@en down to maltose and maltotriose. Bancreatic amylase is the maGor en'yme of starch digestion and& as with sali-ary amylase& $roduces short oligosaccharides& maltotriose& maltose& and "limit de)trins> glucose monomer is not $roduced. t has a $H o$timum of 6.7"7.0. ost of this hydrolysis occurs within the intestinal lumen&
Q. A 20 year old boy com$lains of abdominal $ain < flatulence after consuming dairy $roducts. hich of the following disaccharidases is deficient in the intestinal e$ithelium5 A. altase . #actase
%. somaltase !. ucrase A. . #actase !eficiency of lactase en'yme causes lactose intolerance& which is characteri'ed by non absor$tion of lactose from mil@ < mil@ $roducts. his lactose in colon gets acted u$on by bacteria and gets con-erted into hydrogen & %42 and methane& which leads to bloating. Also& unabsorbed lactose and its $roducts increase the osmotic $ressure of intestinal contents and cause diarrhea. Hydrogen breath test can be diagnostic.
Q. Absor$tion of monosaccharides in the intestinal e$ithelium" identify the incorrect statement: A. #"1 absorbs glucose and galactose . #"1 is an acti-e trans$orter utili'ing AB to trans$ort glucose. %. A cotrans$ort of sodium ions occur along with absor$tion of carbohydrates. !. #L"3& which absorbs fructose is an acti-e trans$orter. A. !. #L"3& which absorbs fructose is an acti-e trans$orter. Glucose and galactose are acti-ely trans$orted by sodium cotrans$orter *$rimarily #1,> acti-e glucose trans$ort is dri-en by the sodium gradient across the a$ical cell membrane . Dor e-ery glucose molecule that is trans$orted across the brush border& Ea + ions *and two accom$anying anions, also are trans$orted across the e$ithelium. Fructose absor$tion occurs by facilitated diffusion> rans$ort occurs not against a concentration gradient but with a carrier $rotein&#L"3 . his $rocess is com$letely inde$endent of glucose absor$tion.
Q. hich of the following trans$orter is associated with $eri$heral u$ta@e of glucose5 A. #L"1 . #L"2
%. #L"; !. #L" A. !. #L" #L $roteins trans$ort glucose and related he)oses. 9ach glucose trans$orter isoform $lays a s$ecific role in glucose metabolism determined by its $attern of tissue e)$ression& substrate s$ecificity& trans$ort @inetics& and regulated e)$ression in different $hysiological conditions. o date& 1; members of the #L/#%2 ha-e been identified. 4n the basis of seFuence similarities& the #L family has been di-ided into three subclasses : %lass : #L 1&2&;& %lass : #L 3&7&J&11 %lass : #L 6&C&10&12 #L 1: mainly $resent in erythrocytes >im$ortant for basal uptake of glucose #L 2: $resent in $ancreatic beta cells *acting as glucose sensor,& renal tubular cells& li-er& intestine*trans$orts glucose& galactose < fructose,. t is a bidirectional $um$. #L ;: $resent in neurons for basal u$ta@e of glucose #L : adi$ose tissue& s@eletal muscle and cardiac muscle> only insulin res$onsi-e glucose trans$orters> peripheral uptake of glucose #L 3: $resent in all tissues for fructose trans$ort.
Q. Dasting for 2 hours decreases the concentration of glucose trans$orters in: A. li-er . s@eletal muscle %. s$leen
!. adrenal corte) A. . s@eletal muscle #L $resent in adi$ose tissue& s@eletal muscle and cardiac muscle is the only insulin res$onsi-e glucose trans$orters& which would decrease in fasting.
Q. etformin& an antidiabetic drug& increases the e)$ressionof following glucose trans$orters in the $eri$heral tissue: A. #L"1 . #L"2 %. #L"; !. #L" A. !. #L" etformin enhances the $hos$horylation of #L" enhancer factor and increases its e)$ression in $eri$heral tissue.
Q. altase inhibitor used in the treatment of diabetes to decease the glucose absor$tion from dietary carbohydrates is : A. nsulin . #B"1 agonist %. metformin !. igitilol
A. !. igitilol Acarbose& igitilol < are al$ha"glucosidase/maltase inhibitors &which slow the $roduction of glucose from dietary carbohydrates& and thus decrease $ost$randial glucose concentration.
Q. he glucose trans$orters $resent in blood brain barrier: A. #"1 . #L"1 %. #"1 < #L"1 !. #L"2 A. %. #"1 < #L"1 %horoid $le)us& which constitutes & contains both #"1 and #L"1.
Q. esticular tissue $redominantly contains which of the following trans$orter: A. #L"2 . #L" %. #L"3 !. #L"1
A. %. #L"3 #L"3& which is a fructose trans$orter is $resent in testes and small intestine. Q. lycolysis" a central $athway in carbohydrate metabolism" incorrect statement is" A. it is an anabolic $athway occurring in cytosol. . it in-ol-es com$lete o)idation of glucose to %42 %. 10 reactions are di-ided into 2 $hases !. o)ygen concentration has no effect on glycolysis A. . it in-ol-es com$lete o)idation of glucose to %42 lycolysis is sim$ly con-ersion of glucose to $yru-ate. Durther fate of $yru-ate de$ends on the $resence or absence of o)ygen or the energy reFuirement. lycolysis has two $hases : $riming $hase and energy yielding $hase. lycolysis can occur both in aerobic as well as anaerobic conditions t occurs in cyto$lasm of the cell
Q. hich of the following $air of en'ymes re$resent irre-ersible ste$s of glycolysis: A. Byru-ate @inase& enolase&Bhos$hoglyceromutase . Byru-ate @inase& BDI"1& he)o@inase %. Byru-ate @inase& BDI"1& lyceraldehyde";"Bhos$hate dehydrogenase
!. Byru-ate @inase& he)o@inase&$hos$hohe)ose isomerase. A. . Byru-ate @inase& BDI"1& he)o@inase
Q. All of the following can be synthesi'ed from glucose"6"$hos$hate e)ce$t: A. Byru-ate . Ribose"3"Bhos$hate %. lycogen !. Datty acid A. !. Datty acid
Q. hich metal is reFuired for the o$timal acti-ity of enolase5 A. %u2+ . g2+ %. o !. ron A. . g2+
Q. Bhos$horylation of glucose ser-es an im$ortant function in cellular metabolism. hat would that $robably be5 A. lucose is con-erted into its acti-ated form. . t decreases the concentration of glucose& which further increases its cellular trans$ort < tra$s it inside the cell. %. lucose"6"Bhos$hate can bind to s$ecific cellular rece$tors. !. lucose"6"Bhos$hate can bind to s$ecific nuclear rece$tors. A. . t decreases the concentration of glucose& which further increases its cellular trans$ort < tra$s it inside the cell.
Q. nsulin increases the acti-ity of gluco@inase en'yme in the he$atocytes by: A. Bhos$horylation . lycosylation %. increasing the transcri$tion of en'yme !. Acetylation A. %. increasing the transcri$tion of en'yme
Q. dentify the isomerase reactions of glycolysis&using the ste$ number from glycolytic $athway shown below.
A. te$1 . te$2 %. te$; !. te$
Q. dentify the transferase reactions of glycolysis&using the ste$ number from glycolytic $athway shown below. A. te$1 . te$2 %. te$ !. te$3
Q. dentify the o)idation"reduction reactions of glycolysis&using the ste$ number from glycolytic $athway shown below. A. te$1 . te$2 %. te$
!. te$6
Q. n the metabolic $athway $resented below& which ste$ re$resents the commited ste$5 A. te$1 . te$2 %. te$; !. te$
Q. lyceraldehyde";"$hos$hate and dihydro)yacetone $hos$hate are intermediates of glycolysis&which are structural isomers of each other. he aldehyde isomer is destined to carry further glycolysis. hat is the metabolic fate of @eto deri-ati-e5 A. lycogen ynthesis . riacylglycerol synthesis %. HB shunt !. Datty acid synthesis
Q. lyceraldehyde";"$hos$hate dehydrogenase is res$onsible for the formation of first high energy com$ound of glycolysis ie 1&;"B. hat is the source of $hos$hate used by this en'yme5 A. AB . B
%. iB !. LB
Q. odoacetate inhibits lyceraldehyde";"$hos$hate dehydrogenase by: A. inding to the sulfydryl grou$ of the en'yme . bloc@ing the acti-e site %. $hos$horylating the en'yme !. acetylation of the en'yme
Q. All of the following can inhibit lyceraldehyde";"$hos$hate dehydrogenase en'yme e)ce$t: A. odoacetate . Arsenate %. Arsenite !. ercury
Q. dentify the correct statement regarding con-ersion of $yru-ate to acetyl %oA: A. t occurs in cytosolic cell com$artment . B!H com$le) cataly'es re-ersible reaction
%. hiamine is an im$ortant coen'yme for the reaction. !. iotin is a $art of the en'yme com$le).
Q. he coen'yme common to the dehydrogenases of both glycolysis and %A cycle is : A. EA! . AB %. EA!BH !. #i$oic acid
Q. Regarding gluconeogenesis& which is the correct statement: A. Reactions ta@e $lace in cytosolic com$artment. . it $roduces energy *e)ergonic, %. t uses carbon s@eletal $ro-ided by amino acids !. it maintains blood glucose during well fed state
Q. hich of the following en'yme would be inhibited on addition of large amounts of egg a-idin5 A. Byru-ate dehydrogenase . #actate dehydrogenase %. Byru-ate carbo)ylase !. alate dehydrogenase
Q. A $atient sus$ected of malaria comes from a chloroFuine resistant 'one. BrimaFuine is administered to the $atient& following which he com$lains of $ain in the bac@ and $assing cola colored urine. #e-els of which of the following metabolic intermediates would be decreased in this $atient5 A. Reduced glutathione . 4)idi'ed glutathione %. lucose"6"Bhos$hate !. 4)idi'ed EA!H