BOARD REVIEW QUESTIONS IN BIOCHEMISTRY
1. What What is the the ion ion prod product uct of wate water? r? A. It is the total number of negatively negatively and positively charged ions in 1 liter of aqueous solution. B. It is the product of the concentrations of hydrogen and hydroxyl ions in an aqueous solution. . It is the number of ioni!ed molecules of water in 1 mole of pure water. ". It is the sum of all hydrogen and hydroxyl ions in an aqueous solution. Ans. B #ef$ %arper&s Biochemistry Biochemistry '( th ed. pp.1)*1+ ,-$ /.0 '. A very very anxious anxious student student hypervent hyperventilate ilates s an hour hour before the biochemi biochemistry stry board board exam. What is the effect of hyperventilation on his -co ' and blood p%? A. -co' decreases and p% increases. B. -co' decreases and p% decreases. . -co' increases and p% decreases. ". -co' increases and p% increases. Ans. A #ef$ %arper&s Biochemistry Biochemistry '( th ed. -p. 1)*1+ ,-$ /.' 2. A prote protein in rich in which which of the followin following g amino amino acids acids will will provide provide the greates greatestt buffering capacity at physiologic p%? A. 3aline B. Aspartic acid acid . ysine ". %istidine Ans. " #ef$ %arper&s Biochemistry Biochemistry '( th ed. p.'4 ,-$ /.0 (. Which of of the following following laboratory laboratory results would would best indicate metabolic al5alosis? A. Increased -co '6 increased p%6 increased %7 2. B. 8ormal -co'6 increased p%6 decreased %7 2. . Increased -co '6 increased p%6 normal %7 2. ". "ecreased -co '6 increased p%6 normal %7 2. Ans. A #ef$ %arper&s Biochemistry Biochemistry '( th ed. p.2/( ,-$ /.0 . What is the the property property of water water that will will contribut contribute e the most to its its ability ability to dissolve dissolve compounds? A. 3ery few interactive forces in its structure. B. %ydrogen bond formation between water and long*chain fatty acids. . ovalent bond formation between salt and water. ". %ydrogen bond formation between water and biochemical molecules. Ans. " #ef$ %arper&s Biochemistry Biochemistry '( th ed. p.1*10 ,-$ /.0
1
4. A child&s child&s develo developmen pmental tal progress progress is noted noted to stop at ' years old. 9he follow following ing year6 s5eletal s5eletal deformities appear. 9he child regresses to a vegetative vegetative state at 1/ years old. :rine examination tests positive for glucosaminoglycans that include most li5ely which of the following? A. ollagen B. ;lycogen . ;ABA ". %eparan sulfate Ans. " #ef. %arper&s Biochemistry Biochemistry '( th ed. p. 402 ,-$ /.' 0. A 2*yea 2*yearr old child child is diagno diagnose sed d to have %urler&s %urler&s syndro syndrome me.. 9he 9he diagn diagnosi osis s of %urler&s syndrome is ,7<9 efficiently made by analy!ing the patient&s "8A for$ A. A region of "8A that does does not encode encode #8A. #8A. B. Alternative forms of the the *Iduronidase *Iduronidase gene. gene. . 9he entire set of genes in one leu5ocyte. ". A nucleotide nucleotide substitution substitution in the *Iduronidase *Iduronidase gene. gene. Ans. B #ef$ %arper&s %arper& s Biochemistry '( th ed. p. 40) ,-$ /.' ). Which Which of the followin following g stateme statements nts regardin regarding g a double double*heli *helical cal molecule molecule of "8A is 9#:=? A. All hydroxyl hydroxyl groups of of pentoses pentoses are involved involved in lin5ages. lin5ages. B. Bases are perpendicular to the axis. . =ach strand is identical. ". =ach strand replicates itself. Ans. B #ef$ %arper&s Biochemistry Biochemistry '( th ed. p.2)4 ,-$ /.0 +. A human human "8A samp sample le is sub>e sub>ecte cted d to increasi increasing ng tempe temperat rature ure until until its ma>or ma>or fraction exhibit optical density changes. A minor fraction of the sample "8A is atypical because it required a higher temperature to denature. 9his atypical minor fraction of sample "8A must have a higher content of$ A. Adenine ytosine B. ytosine ;uanine . Adenine 9hymine 9hymine ". Adenine ;uanine ;uanine Ans. B #ef$ %arper&s Biochemistry Biochemistry '( th ed. p. 2)0*2)) ,-$ /.0 1/. 1/. A newbo newborn rn baby baby has a siblin sibling g with with sic5le sic5le cell anemia anemia and is at ris5 for this disease. disease. 9he appropriate diagnostic test for sic5le cell anemia in this baby would include which of the following? A. "8A amplification B. %emoglobin antibodies . #ed cell counting ". "8A fingerprinting Ans. A #ef$ %arper&s Biochemistry Biochemistry '( th ed. p. (4) ,-$ /.'
2
11. Which of the following would B=<9 describe polymorphism? A. 7ne phenotype6 multiple genotypes B. 8on*random allele association . 7ne locus6 multiple abnormal alleles ". 7ne locus6 multiple normal alleles Ans. " #ef$ %arper&s Biochemistry '( th ed. p. (04 ,-$ /.' 1'. What is that process that occurs at the *position of ytidine and is often correlated with gene inactivation? A. ;ene conversion B.
ust a few minutes? A. 9he higher temperature of mammalian cells allows for an exponentially higher replication rate. B. %undreds of replication for5s wor5 simultaneously on each piece of chromosomal "8A. . ,any #8A polymerases carry out replication simultaneously on chromosomal "8A. ". 9he presence of histones speeds up the rate of chromosomal "8A replication. Ans. B #ef$ %arper&s Biochemistry '( th ed. p. (/0 ,-$ /.0
3
14. unction ". -oint mutation Ans. " #ef$ %arper&s Biochemistry '( th ed. p. 02( ,-$ /.0 10. A culture of bacteria not resistant to 9etracycline develops an infection from a virus that is derived from the lysis of tetracycline*resistant bacteria. ,ost of the bacterial progeny of the original culture is found to have become resistant to tetracycline. What phenomenon has occurred? A. on>ugation B. #ecombination . 9ransformation ". 9ransduction Ans. " #ef$ %arper&s Biochemistry '( th ed. p. (01 ,-$ /.0 1). @ollowing ultraviolet damage to "8A in the s5in6 which of the following is ,7<9 li5ely to occur? A. A specific nuclease detects damaged areas. B. -urine dimmers are formed. . Both strands are cleaved. ". =ndonuclease removes the damaged strand. Ans. A #ef$ %arper&s Biochemistry '( th ed. p. )1( ,-$ /.0 1+. Which of the following statements about the genetic code is the ,7<9 accurate? A. Information is stored as sets of dinucleotide repeats called codons. B. 9he code is degenerate. . 9here are 4( codons6 all of which code for amino acids. ". Information is stored as sets of trinucleotide repeats called codons. Ans. B #ef$ %arper&s Biochemistry '( th ed. p. (22*(2( ,-$ /.0 '/. Which of the following is provided by the 8orthern Blot Analysis? A. "etection of specific base pairs. B. "etection of "8A molecules. . "etection of #8A molecules. ". "etection of proteins. Ans. #ef$ %arper&s Biochemistry '( th ed. p. (0'*(02 ,-$ 1./ '1. In contrast to "8A polymerase6 #8A polymerase$ A. @ills in the gap between the 75a!a5i fragments. B. Wor5s only in a & to 2& direction. . =dits as it synthesi!es. ".
4
Ans. " #ef$ %arper&s Biochemistry '( th ed. p. (1) ,-$ /.0 ''. 9he removal of introns and subsequent self*splicing of ad>acent exons occurs in some portions of primary ribosomal #8A transcripts. 9he splicing of introns in m#8A precursors is$ A. #8A*cataly!ed in the absence of protein. B. arried out by spliceosomes. . ontrolled by #8A polymerase. ". #egulated by #8A helicase. Ans. B #ef$ %arper&s Biochemistry '( th ed. p.('4 ,-$ /.0 '2. What is the function of a promoter site on "8A? A. 9ranscribes repressor B. Initiates transcription . odes for #8A polymerase ". #egulates termination Ans. B #ef$ %arper&s Biochemistry '( th ed. p. ('/ ,-$ 1./ '(. 9he Csigma factorD found in many bacteria is best described as a$ A. or toxin of the death cap mushroom inhibits which of the following? A. "8A primase B. #8A nuclease . "8A ligase ". #8A polymerase Ans. " #ef$ %arper&s Biochemistry '( th ed. p. ('/ ,-$ /.0 '4. 9he consensus sequence &*9A9AAAA*2& found ineu5aryotic genes is almost similar to a consensus sequence observed in pro5aryotes. 9he consensus sequence is important as the$ A. 7nly site of binding of #8A polymerase II. B. -romoter site for all #8A polymerases. . 9ermination site for #8A polymerase II. ". @irst site of binding of a transcription factor for #8A polymerase II. Ans. " #ef$ %arper&s Biochemistry '( th ed. pp. ('1*('' ,-$ /.0
5
'0. 9he so*called CcapsD of #8A molecules$ A. Allow t#8A to be processed. B. 7ccur at the 2&*end of t#8A. . Are composed of poly A. ". Are unique to eu5aryotic m#8A. Ans. " #ef$ %arper&s Biochemistry '( th ed. p. (') ,-$ 1./ '). In bacterial #8A synthesis6 what is the function of the CrhoD factor? A. It binds catabolite repressor to the promoter region. B. It increases the rate of #8A synthesis. . It eliminates the binding of #8A polymerase to the promoter. ". It participates in the proper termination of transcription. Ans. " #ef$ %arper&s Biochemistry '( th ed. p. (1+ ,-$ 1./ '+. Which of the following statements correctly describes the nucleolus of a mammalian cell? A. It differs from that found in bacterial cells in that histones are present. B. It may contain hundreds of copies of genes for different types of ribosomal #8As. . It synthesi!es < r#8A. ". It synthesi!es all ribosomal #8A primary transcripts. Ans. B #efE %arper&s Biochemistry '( th ed. p. (') ,-$ /.0 2/. Which of the following statements correctly describes the synthesis of mammalian m#8A? A. =ach m#8A often encodes several different proteins. B.
6
Ans. " #ef$ %arper&s Biochemistry '( th ed. p.014 ,-$ 1./ 22. Which of the following proteolytic en!ymes is activated by acid hydrolysis of the proen!yme form? A. 9rypsin B. =lastase . -epsin ". arboxypeptidase Ans. #ef$ %arper&s Biochemistry '( th ed. p.424 ,-$ 1./ 2(. Which of the following amino acids is ioni!able in proteins? A. eucine B. %istidine . 3aline ". Alanine Ans. B #ef$ %arper&s Biochemistry '( th ed. p. '+( ,-$ /.0 2. 9he oxygen carrier of muscle is the globular protein myoglobin. Which of the following amino acids is highly li5ely to be locali!ed within the interior of the molecule? A. Arginine B. Aspartic acid . ;lutamic acid ". 3aline Ans. " #ef$ %arper&s Biochemistry '( th ed. p.2 ,-$ /.0 24. Which of the following statements concerning immunoglobulins is most accurate? A. Ig= is the principal antibody in the serum. B. 9he heavy chains are similar in each class of immunoglobulin. . 9he constant regions of the heavy chains are the same in each class of immunoglobulin. ". Ig= is the ma>or immunoglobulin found in external secretions. Ans. #ef$ %arper&s Biochemistry '( th ed. p.01) ,-$ 1./ 20. :nder normal conditions in the blood6 which of the following amino acid residues of albumin is neutral? A. Arginine B. Aspartate . ;lutamine ". %istidine Ans. #ef$ %arper&s Biochemistry '( th ed. p. '+( ,-$ /.0
7
2). A child develops chronic diarrhea and liver inflammation in early infancy when the mother begins using formula that includes corn syrup. =valuation of the child demonstrates sensitivity to fructose in the diet. Which of the following glycosides contains fructose and therefore should be avoided when feeding or treating this infant? A. or metabolic product under normal circumstances by erythrocytes and by muscle cells during intense exercise is recycled through the liver in the ori cycle. 9he metabolite is$ A. 7xaloacetate B. ;lycerol . Alanine ". actate Ans. " #ef$ %arper&s Biochemistry '( th ed. p. '//*'/1 ,-$ /.0 (1. hronic alcoholics require more ethanol than do nondrin5ers to become intoxicated because of a higher level of a specific en!yme levels6 the availability of what other substance is rate*limiting in the clearance of alcohol? A. 8A"% B. 8A" . @A"% ". @A" Ans. B #ef$ %arper&s Biochemistry '( th ed. pp. 4/1*4/2 ,-$ /.' ('. @ollowing a fad diet of s5immed mil5 and yogurt6 an adult female patient experiences abdominal distention6 nausea6 cramping6 and pain followed by watery diarrhea. 9his set of symptoms is observed each time the said meal is consumed. A most li5ely diagnosis is$ A.
8
(2. A percentage of @ilipino population may flush and feel discomfort after drin5ing small amounts of ethanol in alcoholic beverages. 9his reaction is due to genetic variation in an en!yme that metaboli!es the liver metabolite of alcohol6 which is$ A. ,ethanol B. Acetone . Acetaldehyde ". ;lycerol Ans. #ef$ %arper&s Biochemistry '( th ed. p. '4( ,-$ /.0 ((. Which of the following en!ymes cataly!es the high*energy phosphorylation of substrates during glycolysis? A. -yruvate 5inase B. -hosphoglycerate 5inase . 9riosephosphate isomerase ". ;lyceraldehyde*2*phosphate dehydrogenase Ans. " #ef$ %arper&s Biochemistry '( th ed. p.104 ,-$ 1./ (. Which of the following en!ymes gluconeogenesis? A. -yruvate carboxylase B. %exo5inase . -hosphoglycerate 5inase ". @ructose 164*bisphosphatase
is common
to both glycolysis
and
Ans. #ef$ %arper&s Biochemistry '( th ed. p.1+( ,-$ /.0 (4. "uring the first wee5 of a diet of 1// calories per day6 the oxidation of glucose via glycolysis in the liver of a normal +*5g woman is inhibited by the lowering of which of the following? A. itrate B. A9. Fetone bodies ". @ructose*'64*bisphosphatase Ans. " #ef$ %arper&s Biochemistry '( th ed. p.104 ,-$ /.0 (0. @amilial fructo5inase deficiency causes no symptoms because$ A. %exo5inase can phosphorylate fructose. B. ,ost tissues utili!e fructose. . iver fructose*1*phosphate aldolase is still active. ". =xcess fructose spills into the bowel and is eliminated in the feces. Ans. A #ef$ %arper&s Biochemistry '( th ed. p. '1( ,-$ /.0 (). A newborn begins vomiting after feeding6 becomes severely >aundiced6 and has liver disease. 9reatment for possible sepsis is initiated6 and the urine is found to have reducing substances. A blood screen for galactosemia is positive6 and lactose*containing substances are removed from the diet. actose is toxic in this case because$ A. =xcess glucose accumulated in the blood.
9
B. . ".
;alactose is converted to the toxic substance galactitol. ;alactose itself is toxic in even small amounts. ;lucose metabolism is shut down by excess galactose.
Ans. B #ef$ %arper&s Biochemistry '( th ed. p. '/ ,-$ /.' (+. Which of the following en!ymes cataly!es phosphorylation with the use of inorganic phosphate? A. %exo5inase B. -hosphofructo5inase . -hosphoglycerate 5inase ". ;lyceraldehyde*2*phosphate dehydrogenase Ans. " #ef$ %arper&s Biochemistry '( th ed. p. 10+ ,-$ /.0 /. After a well*rounded brea5fast6 which of the following would be expected to occur? A. Increased activity of pyruvate carboxylase B. "ecreased activity of acetyl oA carboxylase . "ecreased rate of glycogenesis ". "ecreased rate of protein synthesis Ans. #ef. ,-$
%arper&s Biochemistry '(th ed. p. 10+ /.0
1. 9he ability of hemoglobin to serve as an effective transporter of oxygen and carbon dioxide between lungs and tissue is explained by which of the ff. properties? A. 9he isolated heme group with ferrous iron binds oxygen much more avidly than carbon dioxide B. 9he G H and H globin chains of hemoglobin have very fifferent primary structures than myoglobin . %emoglobin utili!es oxidi!ed ferric iron to bind oxygen6 in contrats to the ferrous ion myoglobin. ". In contrast to myoglobin6 hemoglobin exhibits greater changes in secondary and tertiary structure after oxygen binding Ans. " #ef. %arper&s Biochemistry '(th ed. p. (24 ,- /.0 '. ontraction of s5eletal muscle is initiated by the binding of calcium to$ A. 9ropomyosin B. 9roponin . ,yosin ". Actomyosin Ans B #ef. %arper&s Biochemistry '(th ed. p. 4)0*4)) ,-$ /.0
10
2.
Which of the following statements correctly describes transport of oxygen by hemoglobin? A. 7xygen binds to hemoglobin more avidly than does carbon monoxide. B. 9he binding of oxygen to hemoglobin causes a valence change in the iron of the heme moiety. . =ach of the four heme moieties binds oxygen independently ". 9he plot of percentage of oxygen bound versus oxygen pressure is sigmoid in shape
Ans. " #ef. %arper&s Biochemistry '(th ed. p. (24 ,-$ /.0 (. Which of the following mutations would produce a severe form of thalassemia? A. "eletion of one G*globin locus B. "eletion of one *globin locus . 7xidation of heme groups to produce methemoglobin ". Altered #8A processing at both Ans. #ef. ,-
" %arper&s Biochemistry '(th ed. p. 02( /.0
. 9he substitution of valine for glutamate at position 4 on the two chains in sic5le cell hemoglobin causes which of the following? A. Increased electrophoretic mobility at p% 0./ B. Increased solubility of deoxyhemoglobin . "ecreased polymeri!ation of deoxyhemoglobin ". :nchanged primary structure Ans. #ef. ,-
A %arper&s Biochemistry '(th ed. p. (04 /.0
4. An increased affinity of hemoglobin for oxygen may result from which of the following? A. Initial binding of oxygen to one of the four sites available in each deoxyhemoglobin molecule B. %igh p% . %igh carbon dioxide levels ". %igh '62*bisphosphoglycerate levels within erthrocytes Ans. #ef. ,-
A %arper&s Biochemistry '(th ed. p. (24 /.0
0. 9he functions of many en!ymes6 membrane transporters6 and other proteins can be quic5ly activated or deactivated by phosphorylation of specific amino acid residues cataly!ed by en!ymes called$ A. yclases B. Finases . -hosphatases ". -roteases Ans #ef. ,-
B %arper&s Biochemistry '(th ed. p. 4(*4 /.0
11
). 9he chemotherapeutic drug fluoracil undergoes a series of chemical changes in vivo that results in a complex such that it is bound to both thymidylate synthase and methylene*tetrahydrofolate. 9he inhibition of deoxythymidylate formation and subsequent bloc5age of cell division is due to$ A. Allosteric inhibition B. ompetitive inhibition . Irreversible inhibition ". 8on*covalent inhibition Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. )4*)) /.0
+. 9he 3max of the en!yme is the$ A. #eciprocal of the absolute value of the intercept of the curve with the x* axis B. #eciprocal of the absolute value of the intercept of the curve with the y* axis . Absolute value of the intercept of the curve with the x*axis ".
B %arper&s Biochemistry '(th ed. p. 0*+/ /.0
4/. In the study of en!ymes6 the sigmoidal plot of substrate concentration versus reaction velocity may indicate$ A. ,ichaelis*,enten Finetics B. ,yoglobin binding oxygen . ooperative binding ". ompetitive inhibition Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. 06 +/ 1./
41. A non competitive inhibitor of an en!yme$ A. Increases Fm with no or little change in 3max B. "ecreases Fm and decreases 3max . "ecreases 3max ". Increases 3max Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. )4*)) /.0
4'. Which of the following statements correctly describes allosteric en!ymes? A. =ffectors may enhance or inhibit substrate binding B. 9hey are not usually controlled by feedbac5 inhibition . 9he regulatory site may be catalytic site ". ,ichaelis*,enten 5inetics describe their activity Ans #ef. ,-
A %arper&s Biochemistry '(th ed. p. 1/(*1/ /.0
12
42. Which of the following en!ymes is regulated primarily through allosteric interaction? A. hymotrypsin B. -yruvate dehydrogenase . ;lycogen phosphorylase ". Aspartate transcarbamoylase Ans #ef. ,-
" %arper&s Biochemistry '(th ed. p. 1/(*1/ /.0
4(. A comatose laboratory technician is rushed into the emergency room.
" %arper&s Biochemistry '(th ed. p. 1') /.'
4. Which of the following statements about flavoproteins is 9#:=? A. 9hey are not oxidi!ed by coen!ymeK B. 9hey receive electrons from cytochrome -(/ in liver mitochondria . 9hey do not participate in oxidation of 8A"% dehydrogenises ". 9hey can be associated with sulfur and nonheme iron Ans #ef. ,-
" %arper&s Biochemistry '(th ed. p. 110*11) /.0
44. As electrons are received and passed down the transport chain6 the various carriers are first reduced with acceptance of the electron and then oxidi!ed with loss of the electron. A patient poisoned by which of the following compounds has the ,7<9 highly reduced state of the respiratory chain carriers? A. Antimycin A B. #otenone . arbon ,onoxide ". -uromycin Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. 1') /.'
40. Which of the following compounds is a member of the electron transport chain? A. 7ctanoyl carnitine B. ytochrome c . 8A"% ". -almitoyl carnitine Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. 1') /.0
13
4). All 5nown effects of cyclic A,- in eu5aryotic cells result from$ A. Activation of the catalytic unit of adenylate cyclase B. Activation of synthetases . Activation of protein 5inase ".
%arper&s Biochemistry '(th ed. p. 14 /.0
4+. 9he connection between oxidative phosphorylation and electron transport is B=<9 described by$ A. =xistence of higher p% in the cisternae of the endoplasmic reticulum than in the cytosol. B.
B %arper&s Biochemistry '(th ed. p. 1'0 /.0
0/. If all potential sources of A9- production are ta5en into account6 the net number of A9- molecules formed per molecule of glucose in aerobic glycolysis is$ A. ' B. 4 . 1) ". 24 Ans #ef. ,-
B %arper&s Biochemistry '(th ed. p. 104*1)( /.0
01. Which of the following reactions generates A9-L A. ;lucose 4*phosphate to @ructose 4*phosphate B. ;lucose to ;lucose 4*-hosphate . @ructose 4*phosphate to @ructose 164*bisphosphate ". -hosphoenolpyruvate Ans #ef. ,-
" %arper&s Biochemistry '(th ed. p. 104*1)( /.0
0'. which of the following products of triacylglycerol brea5down and subsequent * oxidation may undergo gluconeogenesis? A. -ropionyl oA B. Acetyl oA . All 5etone bodies ".
A %arper&s Biochemistry '(th ed. p. ')( /.0
02. Which of the following regulates lipolysis in adipocytes? A. Activation of fatty acid synthesis mediated by cA,B. Activation of triglyceride lipase as a result of hormone*stimulated increases in cA,- production by insulin . ;lyerol phosphorylation to prevent futile esterification of fatty acids ". Activation of cA,- production by insulin
14
Ans #ef. ,-
" %arper&s Biochemistry '(th ed. p. '40 /.0
0(. Inhibition of A9- synthesis during oxidative phosphorylation by oligomycin is thought to be due to$ A. Bloc5ing of the proton gradient between 8A"%*K reductase M K% ' B. Bloc5ing of the proton gradient between cytochrome 1 and cytochrome . "issociation of cytochrome c from mitochondrial membranes ". Inhibition of mitochondrial A9-ase Ans #ef. ,-
" %arper&s Biochemistry '(th ed. p. 0/1 /.0
0. 9he reactions of the urea cycle occur$ A. In the cytosol B. In the mitochondrial matrix . In the mitochondrial matrix M the cytosol ". 7nly in lysosomes Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. 2/1*2)/ /.0
04. A newborn becomes progressively lethargic after feeding and increases his respiratory rate. %e becomes virtually comatose6 responding only to painful stimuli6 and exhibits mild respiratory al5alosis.
" %arper&s Biochemistry '(th ed. p. '40 /.0
00. 9he thyroid hormone thyroxine 9 ( is derived from$ A. 9hreonine B. 9yrosine . 9hiamine ". 9ryptophan Ans #ef. ,-
B %arper&s Biochemistry '(th ed. p. 2(*24 /.0
0). Which of the metabolites below is a precursor of tyrosine? A. *dihydroxyphenylalanine "7-A B. "opamine . 8orepinephrine ". -henylalanine Ans #ef. ,-
" %arper&s Biochemistry '(th ed. p. '+4*'+0 /.0
15
0+. Which clinical laboratory observation is suggestive of %artnup&s disease? A. %igh fecal levels of tryptophan and indole derivatives B. =levated plasma tyrosine and methionine levels . =levation of glutamine in blood and urine ". =xtremely high levels of citrulline in urine Ans #ef. ,-
A %arper&s Biochemistry '(th ed. p. 2''*2' /.0
)/. 9he important receive group of glutathione in its role as antioxidant is$ A.
B %arper&s Biochemistry '(th ed. p. 02 /.0
)1. A newborn develops >aundice that requires laboratory evaluation. Which of the following porphyrin derivatives is con>ugated6 reacts directly6 and is a ma>or component of bile? A.
" %arper&s Biochemistry '(th ed. p. 24 /.0
)'. Which of the following poryphrins give stools their characteristic brown color? A. Biliverdin B. :robilinogen . %eme ".
" %arper&s Biochemistry '(th ed. p. 2( /.0
)2. hylomicrons6 I"6 "6 and 3" are all serum lipoproteins. What is the correct ordering of these particles from the lowest to the highest density? A. "6 I"6 3"6 hylomicrons B. hylomicrons6 3"6 I"6 " . 3"6 I"6 "6 hylomicrons ". hylomicrons6 I"6 3"6 " Ans #ef. ,-
B %arper&s Biochemistry '(th ed. p. 0/) /.0
)(. eramide is a precursor to which of the following compounds? A. -hosphatidyl serine B.
B %arper&s Biochemistry '(th ed. p. '/*'' /.0
16
).
Which of the following steps in cholesterol biosynthesis is thought to be rate* limiting and the locus of metabolic regulation? A. ;eranyl pyrophosphate to @arnesyl pyrophosphate B.
Ans #ef. ,-
B %arper&s Biochemistry '(th ed. p. '0( /.0
)4. %umans ,7<9 easily tolerate a lac5 of which of the following nutrients? A. -rotein B. Iodine . arbohydrate ". ipid Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. ')*')4 /.0
)0. A deficiency in 3itamin B1' causes$ A. heilosis B. Beriberi . -ernicious anemia ".
" %arper&s Biochemistry '(th ed. p. 41'*412 /.0
)). Which of the following vitaminswould ,7<9 li5ely become deficient in a person who develops a completely carnivorous lifestyle? A. 9hiamine B. 8iacin . obalamin ". 3itamin Ans #ef. ,-
" %arper&s Biochemistry '(th ed. p. 41'*412 /.0
)+. @ully activated pyruvate carboxylase depends upon the presence of$ A. ,alate and 8iacin B. Acetyl oA and Biotin . Acetyl oA and 9hiamine pyrophosphate ". 7xaloacetate Ans #ef. ,-
B %arper&s Biochemistry '(th ed. p. 1+( /.0
+/. Biotin is involved in which of the following types of reactions? A. %ydroxlations B. arboxylations . "ecarboxylations ". "ehydrations Ans #ef. ,-
B %arper&s Biochemistry '(th ed. p. 4/4*4/0 /.0
17
+1. Which of the following conditions would primarily produce a functional deficiency of 3itamin F? A. oumadin 9herapy B. Broad
A %arper&s Biochemistry '(th ed. p. 0'0 /.0
+'. A 2 month old boy presents with poor feeding M growth6 hypotonia6 lactic acidemia6 and mild acidosis. 9he pyruvate to lactate ratio is high6 and there is decreased conversion of pyruvate to Acetyl oA. Which of the following may be considered for therapy? A. 9hiamine B. @@A . Biotin ". 3itamin Ans #ef. ,-
A %arper&s Biochemistry '(th ed. p. 1)2 /.'
+2. A '*year old child presents with cough and bronchitis6 growth failure6 M chronic diarrhea with light*colored foul smelling stools. A deficiency of which vitamin should be considered? A. 3it B4 B. 3it . 3it A ". 3it B1 Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. 41(*410 /.'
+(. an infant presents with prominent forehead6 bowing of the limbs6 broad M tender wrists6 swelling at the costochondral >unction of the ribs6 and irritability. Which of the following treatments is the most appropriate for this patient? A. #emoval of eggs from diet B. ,il5 M
%arper&s Biochemistry '(th ed. p. 412 /.'
+. Allopurinol effectively treats gout but has 87 effect on the severe neurological symptoms of esch*8yhan patients because it does not$ A. "ecrease de 8ovo purine synthesis B. "ecrease de 8ovo -yrimidine syntheis . Inhibit xanthine oxidase ". Increase -#-- levels Ans #ef. ,-
A %arper&s Biochemistry '(th ed. p. 20) /.0
18
+4. Which of the following would rule out hyperuricemia in a ptient? A. esch*8yhan synthesis B. ;out . arbonage phosphate deficiency ". Nanthine oxidase hyperactivity Ans #ef. ,-
%arper&s Biochemistry '(th ed. p. 2)1 /.0
+0. Which of the following contributes nitrogen atom to both purine M pyrimidine rings? A. Aspartate B. arbonage -7 ( . 7' +). What is the end product of fatty acid synthase activity in human? A. -almitic acid B. -almetoleic acid . inoleic ". Arachidonic acid Ans #ef. ,-
A %arper&s Biochemistry '(th ed. p. '14*''2 /.0
++. @or every ' moles of free glycerol released by lipolysis of triglycerides in adipose tissue? A. 1 mole of glucose can be synthesi!ed via gluconeogenesis B. ' moles of triacrylglyceride is released . ' moles of @@A is released ". 2 moles of Acyl oA is produced Ans #ef. ,-
A %arper&s Biochemistry '(th ed. p. '40 /.0
1//. A ( year old man ha s a mild heart attac5 and is placed on diet and ,evastatin therapy. Which of the following will result in this therapy? A. ow blood glucose level B. ow blood "s . %igh blood cholesterol ". ow oxidation of @a Ans #ef. ,-
B %arper&s Biochemistry '(th ed. p. ')1 /.0
19
20
