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1.Fatty acid synthase (FAS) differs from β-oxidation in all of the following ways EXCEPT: a. occurs in cytosol. b. uses NADPH for oxidoreductase reactions. c. acyl carrier protein linked intermediates. d. all of the enzymes are on one polypeptide. e. all are true.
e. all are true.
What type of linkage occurs between ACP and the intermediates in fatty acid biosynthesis? a. an ester b. a thioester c. an amide d. an ether e. an acetal
b. a thioester
3.There is no transporter for acetyl-CoA to exit the mitochondria, so the carbons must be converted to ____ for transport to the cytosol. a. acetone b. butyrate c. citrate d. pyruvate e. malonate
c. citrate
The main source(s) of NADPH for fatty acid biosynthesis is (are): a. TCA cycle. b. oxidative phosphorylation. c. malic enzyme and the pentose phosphate pathway. d. the conversion of OAA to malate by malate dehydrogenase. e. glycolysis
c. malic enzyme and the pentose phosphate pathway.
Acetyl-CoA carboxylase in animals is regulated by all of the following EXCEPT: a. allosterically stimulated by citrate. b. phosphorylation by protein kinase A. c. allosterically inhibited by palmitoyl-CoA. d. allosterically stimulated by ATP. e. all are correct.
d. allosterically stimulated by ATP.
The committed step in cholesterol biosynthesis is catalyzed by: a. HMG-CoA synthase. b. mevalonate kinase. c. HMG-CoA reductase. d. squalene monooxygenase. e. HMG-CoA lyase.
c. HMG-CoA reductase.
9.The carbons of sphinganine are derived from: a. palmitate and glycerol. b. arachidonate and glycine. c. fatty alcohol and dihydroxyacetone phosphate (DHAP). d. palmitate and serine. e. none of the above.
d. palmitate and serine.
25.CDP-diacylglycerols are precursors for the synthesis of all EXCEPT: a. phosphatidylethanolamine. b. phosphatidyl glycerol. c. cardiolipins. d. phosphatidylinositol. e. all are true.
a. phosphatidylethanolamine.
Which of the following is correctly paired with its effect upon fatty acid synthesis? a. palmitoyl CoA: activates b. glucagon: activates c. insulin: inhibits d. citrate: activates e. NADPH: inhibits
d. citrate: activates
. Which of the following CANNOT be made from acetyl CoA? a. cholesterol b. pyruvate c. acetoacetate d. squalene e. palmitate
b. pyruvate
.Components for plasmalogen biosynthesis include all EXCEPT: a. CDP-ethanolamine. b. fatty acyl-CoA. c. NADPH, NADH and O2. d. long-chain alcohol. e. glycerol.
e. glycerol.
The correct sequence for synthesis of mevalonate from acetyl-CoA is: A. HMG-CoA synthase B. formation of 3-hydroxy-3-methylglutaryl-CoA C. β-ketothiolase catalyzed condensation D. HMG-CoA reductase activity E. Formation of acetoacetyl-CoA a. E, C, D, A, B b. C, D, A, B, E c. E, B,…
e. C, E, A, B, D
.All are characteristic of acetyl-CoA carboxylase EXCEPT: a. allosteric inhibition by palmitoyl-CoA. b. biotin carboxylase and transcarboxylase subunits. c. biotin carboxyl carrier protein subunits. d. citrate shifts the enzyme toward the active polymer. e. all are correct
e. all are correct
Which of the following statements regarding phosphorylation of acetyl-CoA carboxylase is correct? a. phosphorylation causes activation only in the presence of palmitoyl-CoA b. phosphorylation is a result of glucagon binding to its receptor c. high [citrate] inhibits the phosphorylated …
e. both b and d are true
How many NADPH are required to make one molecule of palmitic acid from acetyl CoA? a. 7 b. 8 c. 14 d. 16 e. 21
c. 14
Which of the following molecules would have an inhibitory effect upon the overall process of fatty acid synthesis? a. citrate b. insulin c. palmitoyl CoA d. NADPH e. none of the above
c. palmitoyl CoA
4.____ is an intermediate on the biosynthetic pathway from cholesterol to both male and female hormones. a. Aldosterone b. Progesterone c. Cortisol d. Estradiol e. Testosterone
b. Progesterone
Lipoproteins consist of a core of ____ and ____ surrounded by a single layer of ____, into which is inserted ____ and ____. a. proteins; triacylglycerols; cholesterol esters; phospholipids; cholesterol b. triacylglycerols; cholesterol esters; phospholipids; proteins; cholesterol c. ph…
b. triacylglycerols; cholesterol esters; phospholipids; proteins; cholesterol
3.What reaction does glutamate dehydrogenase (GDH) catalyze? a. The reductive amination of α-ketoglutarate to yield glutamate. b. Phosphorylation of carbamate to yield carbamoyl-phosphate. c. The amidation of the γ-carboxyl group of glutamate to form glutamine. d. The deadenylation of…
a. The reductive amination of α-ketoglutarate to yield glutamate.
The reaction, glutamate + NAD(P)+ + H2O → NH4 + + α-ketoglutarate + NAD(P)H + H+ , is catalyzed by: a. Nitrogenase. b. carbamoyl-phosphate synthetase (CPS-I). c. glutamate dehydrogenase (GDH). d. glutamine synthetase (GS). e. none are true.
c. glutamate dehydrogenase (GDH).
ll are characteristics of Maple Syrup Urine Disease EXCEPT: a. hereditary enzyme defect. b. elevated levels of val, leu, and ile and their corresponding α-keto acids in blood and urine. c. restrictive intake of proteins with val, leu and ile is required. d. fatal without detection and…
e. elevated blood levels of acetoacetate and β-hydroxybutyrate.
What would be a result of a high [Gln]/[α-KG] ratio? a. Increase in deadenylation of glutamine synthetase. b. An increase in activity of glutamine synthetase. c. An increase in the degree of adenylation of glutamine synthetase. d. Inhibition of AT:PIIA and stimulation of AT:PIID. e. …
c. An increase in the degree of adenylation of glutamine synthetase.
Aspartate is formed from transamination of: a. asparagine. b. aspartame. c. oxaloacetate. d. citrate. e. α-ketoglutarate.
c. oxaloacetate.
6.Transamination of pyruvate with glutamate as amino donor gives: a. alanine. b. serine. c. cysteine. d. aspartate. e. valine.
a. alanine.
All of the following are true of the urea cycle EXCEPT: a. It helps in the excretion of excess nitrogen. b. It is mainly confined to the liver. c. It is linked to the citric acid cycle through fumarate. d. Stimulation of carbamoyl-phosphate synthetase I (CPS-I) decreases the activity …
d. Stimulation of carbamoyl-phosphate synthetase I (CPS-I) decreases the activity of the urea cycle.
Amino acids biosynthesized from aspartate include all EXCEPT: a. asparagine. b. threonine. c. methionine. d. lysine. e. glutamate
e. glutamate
All are convergent metabolic intermediates of α-amino acid carbon skeletons EXCEPT: a. Citrate. b. α-ketoglutarate. c. Oxaloacetate. d. succinyl-CoA
a. Citrate.
1.The term ketogenic amino acids refers to amino acids: a. that are precursors for glucose synthesis. b. degraded to yield acetyl CoA or acetoacetate. c. that can not be converted to fatty acids or ketone bodies. d. degraded to yield succinyl-CoA, pyruvate, α-ketoglutarate, fumarate a…
b. degraded to yield acetyl CoA or acetoacetate.
Ornithine serves three metabolically important roles, but is not found in proteins. What is one of the important roles of ornithine? a. amine donor for many transamination reactions b. an intermediate in the urea cycle c. involved in the synthesis of serine, which serves as a precurso…
b. an intermediate in the urea cycle
All of the following statements about nucleotides are true EXCEPT: a. They are produced by nearly all organisms. b. The rate of proliferation of a cell can determine the amount of DNA and RNA synthesized per unit of time. c. Uridine nucleotide derivatives of carbohydrates are common i…
e
Adenylosuccinase (adenylosuccinate lyase) catalyzes the reaction to remove ____ after ____ has formed an amide with a carbonyl group in purine biosynthesis. a. succinate; glutamate b. succinate; aspartate c. fumarate; alanine d. fumarate; aspartate e. α-ketoglutarate; glutamate
d
The fate of IMP is regulated by relative levels of ____ and ____; and energy to drive AMP synthesis is provided by ____, and energy for GMP synthesis by ____. a. IMP; PRPP; ATP; GTP b. PRPP; ATP; ATP; GTP c. AMP; ATP; GTP; ATP d. AMP; GMP; GTP; ATP e. IMP; GMP; ATP; GTP
d
The reaction, base + PRPP → nucleoside-5-phosphate + PPi is catalyzed by the enzyme: a. nucleotide diphosphate kinase. b. phosphoribosyltransferase. c. ribose-5-phosphate pyrophosphokinase. d. adenylate kinase. e. GMP synthetase.
b. phosphoribosyltransferase.
Allopurinol is an analog of ____ that tightly binds to ____ and prevents ____ formation. a. hypoxanthine; xanthine oxidase; uric acid b. guanine; guanine deaminase; xanthine c. inosine; xanthine oxidase; xanthine d. hypoxanthine; guanine deaminase; xanthine e. none of the above
a. hypoxanthine; xanthine oxidase; uric acid
n mammals CPS-II is the regulated step on pyrimidine biosynthesis; however, in bacteria ____ is the regulated step. a. dihydroorotase b. aspartate transcarbamoylase (ATCase) c. OMP decarboxylase d. dehydroorotate d
b. aspartate transcarbamoylase (ATCase)
Thymidylate synthase synthesizes dTMP from ____ by ____ utilizing the coenzyme ____. a. dCTP; carboxylation; biotin b. dUMP; methylation; THF c. dCMP; methylation; THF d. dGMP; phosphorylation; ATP e. dUMP; phosphorylation; ATP
b. dUMP; methylation; THF
3.Which of the following is a source of 2 carbon atoms of the purine ring system? a. aspartate b. carbon dioxide c. glycine d. glutamine e. glutamic acid
c. glycine
6.Which form of the folate coenzyme is directly involved in sythesis of the purine ring? a. N5 ,N10-methenyl THF b. N10-formyl THF c. N5 -formyl THF d. tetrahydrofolate e. dihydrofolate
b. N10-formyl THF

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