Test Amino I Pur1

A 27 year old man complains of genital sores. On questioning, the physician learns that the patient recently had an unsafe sexual contact. The physician initiates therapy with antiviral agent. Which of the following enzymes is inhibited by the antiviral agent ? a) adenosine deaminase b) hypoxanthine guanine phosphoribosyltransferase (HGPRT) c) phosphoribosylpyrpphosphate (PRPP) synthase d) thymidine kinase e) xanthine oxidase

A 27 year old man complains of genital sores. On questioning, the physician learns that the patient recently had an unsafe sexual contact. The physician initiates therapy with antiviral agent. Which of the following enzymes is inhibited by the antiviral agent ? a) adenosine deaminase b) hypoxanthine guanine phosphoribosyltransferase (HGPRT) c) phosphoribosylpyrpphosphate (PRPP) synthase d) thymidine kinase e) xanthine oxidas

The chemotherapeutic agent, methotrexate, is an inhibitor of A.thymidylate synthase B.aspartate transcarbamoylase C.dihydrofolate reductase D.PRPP synthetase E.carbamoyl phosphate synthetase

The chemotherapeutic agent, methotrexate, is an inhibitor of A.thymidylate synthase B.aspartate transcarbamoylase C.dihydrofolate reductase D.PRPP synthetase E.carbamoyl phosphate synthetase

Azaserine inhibits purine biosynthesis at the step A.PRPP + glutamine -> 5- phosphoribosylamine. B.5-phosphoribosylamine + glycine -> 5-phosphoribosylglycineamide. C.IMP -> AMP. D.folic acid -> tetrahydrofolic acid (THFA).

Azaserine inhibits purine biosynthesis at the step A.PRPP + glutamine -> 5- phosphoribosylamine. B.5-phosphoribosylamine + glycine -> 5-phosphoribosylglycineamide. C.IMP -> AMP. D.folic acid -> tetrahydrofolic acid (THFA).

The lack of active hypoxanthine-guanine phosphoribosyl transferase causes a human genetic disease known as A.alkaptonuria. B.familial hypercholesterolemia. C.phenylketonuria. D.Lesch-Nyhan syndrome. E.Tay-Sachs disease.

The lack of active hypoxanthine-guanine phosphoribosyl transferase causes a human genetic disease known as A.alkaptonuria. B.familial hypercholesterolemia. C.phenylketonuria. D.Lesch-Nyhan syndrome. E.Tay-Sachs disease.

The principal feedback control of pyrimidine biosynthesis in humans occurs at the step catalyzed by the enzyme A.carbamoyl phosphate synthetase (cytosolic). B.aspartate transcarbamoylase. C.dihydroorotase. D.dihydroorotate dehydrogenase. E.thymidylate synthase.

The principal feedback control of pyrimidine biosynthesis in humans occurs at the step catalyzed by the enzyme A.carbamoyl phosphate synthetase (cytosolic). B.aspartate transcarbamoylase. C.dihydroorotase. D.dihydroorotate dehydrogenase. E.thymidylate synthase.

Which of the following amino acids are directly involved in purine biosynthesis EXCEPT which one? A.glutamine B.aspartic acid C.histidine D.Glycine

Which of the following amino acids are directly involved in purine biosynthesis EXCEPT which one? A.glutamine B.aspartic acid C.histidine D.Glycine

Which of the enzyme first recognizes allopurinol as a substrate and is then inhibited by the product of enzyme catalysis. A.PRPP synthetase B.Hypoxanthine-guanine phosphoribosyl transferase C.Adenosine deaminase D.PRPP amidotransferase E.Xanthine oxidase

Which of the enzyme first recognizes allopurinol as a substrate and is then inhibited by the product of enzyme catalysis. A.PRPP synthetase B.Hypoxanthine-guanine phosphoribosyl transferase C.Adenosine deaminase D.PRPP amidotransferase E.Xanthine oxidase

Severe Combined Immunodeficiency Syndrome is most often due to a deficiency in A.adenosine deaminase. B.xanthine oxidase. C.ribonucleotide reductase. D.thymidylate synthase. E.hypoxanthine-guanine phosphoribosyl transferase.

Severe Combined Immunodeficiency Syndrome is most often due to a deficiency in A.adenosine deaminase. B.xanthine oxidase. C.ribonucleotide reductase. D.thymidylate synthase. E.hypoxanthine-guanine phosphoribosyl transferase.

In the figure below, the nitrogen atoms indicated in the purine ring structure by (1) are derived from a).histidine. b)lysine. c)aspartate. d)glycine. e)glutamine

In the figure below, the nitrogen atoms indicated in the purine ring structure by (1) are derived from a).histidine. b)lysine. c)aspartate. d)glycine. e)glutamine

The nucleotide, dGTP, consists of A. guanine, ribose, and three phosphoryl groups B. GMP plus two phosphoryl groups C. guanine, 2-deoxyribose, and three phosphoryl groups D. guanosine, 2-deoxyribose, and three phosphoryl groups E. guanine, ribose and two phosphoryl groups

The nucleotide, dGTP, consists of A. guanine, ribose, and three phosphoryl groups B. GMP plus two phosphoryl groups C. guanine, 2-deoxyribose, and three phosphoryl groups D. guanosine, 2-deoxyribose, and three phosphoryl groups E. guanine, ribose and two phosphoryl groups

Gout and Lesch Nyhan Syndrome are both due to unusually high levels of what? A. uric acid B. urea C. urinate D. niacin E. heme groups

Gout and Lesch Nyhan Syndrome are both due to unusually high levels of what? A. uric acid B. urea C. urinate D. niacin E. heme groups

Methotrexate works in chemotherapy because it 1. prevents fatty acid metabolism 2. prevents DNA synthesis 3. damages RNA 4. prevents conversion of dUMP to dTMP by inhibiting dihydrofolate reductase. Answer A if 1, 2, and 3 are correct Answer B if 1 and 4 are correct Answer C if 2 and 4 are correct Answer D if only 4 is correct Answer E if all are correct

Methotrexate works in chemotherapy because it 1. prevents fatty acid metabolism 2. prevents DNA synthesis 3. damages RNA 4. prevents conversion of dUMP to dTMP by inhibiting dihydrofolate reductase. Answer A if 1, 2, and 3 are correct Answer B if 1 and 4 are correct Answer C if 2 and 4 are correct Answer D if only 4 is correct Answer E if all are correct

1. An enzyme was isolated from human liver cells. 2. It catalyzed the conversion of PRPP (5-2.phosphoribosylpyrophosphate) to 5 phosphoribosylamine. 3. the enzyme catalize this reaction is amidophosphoribosyl transferase 4. enzyme required glutamine Answer A if 1, 2, and 3 are correct Answer B if 1 and 4 are correct Answer C if 2 and 4 are correct Answer D if only 4 is correct Answer E if all are correct

1. An enzyme was isolated from human liver cells. 2. It catalyzed the conversion of PRPP (5-2.phosphoribosylpyrophosphate) to 5 phosphoribosylamine. 3. the enzyme catalize this reaction is amidophosphoribosyl transferase 4. enzyme required glutamine Answer A if 1, 2, and 3 are correct Answer B if 1 and 4 are correct Answer C if 2 and 4 are correct Answer D if only 4 is correct Answer E if all are correct

The lack of active hypoxanthine-guanine phosphoribosyl transferase causes a human genetic disease known as A.alkaptonuria. B.familial hypercholesterolemia. C.phenylketonuria. D.Lesch-Nyhan syndrome. E.Tay-Sachs disease.

The lack of active hypoxanthine-guanine phosphoribosyl transferase causes a human genetic disease known as A.alkaptonuria. B.familial hypercholesterolemia. C.phenylketonuria. D.Lesch-Nyhan syndrome. E.Tay-Sachs disease.

Which of the following groups of enzymes is most involved in the disposal of excess nitrogen from protein in the diet ? a) aminoacid oxidases and arginase b) argininosuccinate lyase and cytosolic carbamoyl phosphate synthetase II c) glutaminase and amino acid oxidases d) glutamine synthetase and urease e) transaminases and glutamate dehydrogenase

Which of the following groups of enzymes is most involved in the disposal of excess nitrogen from protein in the diet ? a) aminoacid oxidases and arginase b) argininosuccinate lyase and cytosolic carbamoyl phosphate synthetase II c) glutaminase and amino acid oxidases d) glutamine synthetase and urease e) transaminases and glutamate dehydrogenase

A 28 year old woman with Cushing’s syndrome has hyperglycemia. Which of the following enzymes is most likely causing the hyperglycemia ? a) aspartate aminotransferase b) capillary lipoprotein lipase c) phosphoenolpyruvate carboxykinase d) pyruvate carboxylase e) pyruvate dehydrogenase

A 28 year old woman with Cushing’s syndrome has hyperglycemia. Which of the following enzymes is most likely causing the hyperglycemia ? a) aspartate aminotransferase b) capillary lipoprotein lipase c) phosphoenolpyruvate carboxykinase d) pyruvate carboxylase e) pyruvate dehydrogenase

Which amino acids are used in the synthesis of heme ? Glicine Phenylalanine Arginine Tyrosin Methionine

Which amino acids are used in the synthesis of heme ? Glicine Phenylalanine Arginine Tyrosin Methionine

Which of following aminoacids form pyruvate ?. Alanine Phenylalanine Arginine Tyrosin Methionine

Which of following aminoacids form pyruvate ?. Alanine Phenylalanine Arginine Tyrosin Methionine

Choose aminoacid that is converted to α-ketoglutarate in the citric acid cycle Arginine Alanine Serine Phenylalanine Leucine.

Choose aminoacid that is converted to α-ketoglutarate in the citric acid cycle Arginine Alanine Serine Phenylalanine Leucine.

Choose enzyme that cooperates with PLP (pyridoxal phosphate) Arginase Aminotranspherase Glutamate dehydrogenase Ornithine transcarboxylase Glucose6-phosphatase

Choose enzyme that cooperates with PLP (pyridoxal phosphate) Arginase Aminotranspherase Glutamate dehydrogenase Ornithine transcarboxylase Glucose6-phosphatase

All of the following may be derived from intermediates in glycolysis or the TCA cycle in humans EXCEPT a)

alanine.

b)

aspartate.

c)

glutamate.

d)

methionine.

e)

glutamine.

All of the following may be derived from intermediates in glycolysis or the TCA cycle in humans EXCEPT a)

alanine.

b)

aspartate.

c)

glutamate.

d)

methionine.

e)

glutamine.

Amino acid residues that can undergo reversible phosphorylation and dephosphorylation as a means of regulating activity include a)

Cys and Ser.

b)

Arg, Lys, and Ser.

c)

Asp, Glu, and Ser.

d)

Met, Trp, and Ser.

e)

Thr, Tyr, and Ser.

Amino acid residues that can undergo reversible phosphorylation and dephosphorylation as a means of regulating activity include a)

Cys and Ser.

b)

Arg, Lys, and Ser.

c)

Asp, Glu, and Ser.

d)

Met, Trp, and Ser.

e)

Thr, Tyr, and Ser.

Which of the following describes the side chain of isoleucine? a)

contains a sulfhydryl group

b)

contains a branched chain hydrocarbon

c)

contains an aromatic ring

d)

doesn't have a side chain

e)

contains an acidic side chain

Which of the following describes the side chain of isoleucine? a)

contains a sulfhydryl group

b)

contains a branched chain hydrocarbon

c)

contains an aromatic ring

d)

doesn't have a side chain

e)

contains an acidic side chain

An amino acid found in virtually all triplet repeats of a collagen polypeptide is A.alanine. B.glycine. C.glutamine. D.lysine. E.phenylalanine.

An amino acid found in virtually all triplet repeats of a collagen polypeptide is A.alanine. B.glycine. C.glutamine. D.lysine.

E.phenylalanine. Which of the following amino acids may participate in the formation of covalent crosslinks that stabilize the tertiary structure of many globular proteins? A.methionine B.cysteine C.serine D.leucine E.Histidine

Which of the following amino acids may participate in the formation of covalent crosslinks that stabilize the tertiary structure of many globular proteins? A.methionine

B.cysteine C.serine D.leucine E.Histidine Which of the following amino acid residues may participate in hydrophobic bonding in a globular protein? A.glycine B.phenylalanine C.lysine D.serine E.Aspartate

Which of the following amino acid residues may participate in hydrophobic bonding in a globular protein?

A.glycine B.phenylalanine C.lysine D.serine E.Aspartate Which of the following amino acids contributes both carbon and nitrogen atoms to the purinering? A.aspartate B.glycine C.glutamine D.lysine E.cysteine

Which of the following amino acids contributes both carbon and nitrogen atoms to the purinering? A.aspartate

B.glycine C.glutamine D.lysine E.cysteine An enzyme which is subject to feedback inhibition by heme is A.heme synthase. B.delta-aminolevulinate synthase. C.uroporphyrinogen III cosynthase. D.pyridoxal phosphate synthase. E.heme oxygenase.

An enzyme which is subject to feedback inhibition by heme is A.heme synthase. B.delta-aminolevulinate synthase.

C.uroporphyrinogen III cosynthase. D.pyridoxal phosphate synthase. E.heme oxygenase. The enzyme enterokinase initiates the activation of pancreatic proteases by converting A.pepsinogen to pepsin. B.procarboxypeptidase A to carboxypeptidase A. C.trypsinogen to trypsin. D.chymotrypsinogen to chymotrypsin. E.procarboxypeptidase B to carboxypeptidase B. Amino acids which are strictly ketogenic are A.lysine and leucine. B.aspartate and asparagine. C.cysteine and serine. D.methionine and valine. E.proline and arginine. Ammonia may be released from most amino acids for use in urea synthesis by the sequential action of which enzymes? A.amino transferase and glutamine synthetase B.glutamine synthetase and glutamate dehydrogenase C.amino transferase and glutamate dehydrogenase D.amino transferase and lactate dehydrogenase E.amino transferase and urease All of the following compounds EXCEPT which one would be expected to be found in excess amounts in the urine of an individual with phenylketonuria? A.phenylpyruvic acid B.phenyllactic acid C.tyrosine D. phenylacetic acid Enzymes involved in the digestion of dietary protein in the small intestine include all of the following EXCEPT A.trypsin. B.elastase. C.chymotrypsin. D.carboxypeptidase A. E.pepsin. The excretion of urea 1.is the major form of nitrogen excretion in mammals. 2.will increase in amount as the amount of protein in the diet increases. 3.is dependent upon an active mitochondrial carbamoyl phosphate synthetase in the liver.

4.is regulated by glutaminase in the kidney. A.Mark answer 'A' if statements 1, 2 and 3 are correct. B.Mark answer 'B' if statements 1 and 3 are correct. C.Mark answer 'C' if statements 2 and 4 are correct. D.Mark answer 'D' if ONLY statement 4 is correct. E.Mark answer 'E' if statements are ALL correct, or they are ALL incorrect. In the (gamma) glutamyl cycle for amino acid transport 1.the amino acid is transferred into the cell as a gamma-glutamyl derivative. 2.glutathione is re-synthesized from glycine, cysteine and glutamate. 3.3 ATP are required for transport of one amino acid. 4.glutathione is oxidized to its disulfide form. A.Mark answer 'A' if statements 1, 2 and 3 are correct. B.Mark answer 'B' if statements 1 and 3 are correct. C.Mark answer 'C' if statements 2 and 4 are correct. D.Mark answer 'D' if ONLY statement 4 is correct. E.Mark answer 'E' if statements are ALL correct, or they are ALL incorrect. Which of the following metabolic intermediates is produced directly from an amino acid after the action of an amino transferase? 1.alpha ketoglutarate. 2.oxaloacetate. 3.pyruvate. 4.succinate. A.Mark answer 'A' if statements 1, 2 and 3 are correct. B.Mark answer 'B' if statements 1 and 3 are correct. C.Mark answer 'C' if statements 2 and 4 are correct. D.Mark answer 'D' if ONLY statement 4 is correct. E.Mark answer 'E' if statements are ALL correct, or they are ALL incorrect. In the conversion of the alpha-amino group of various amino acids to urea 1.the amino groups enter the urea cycle in the form of carbamyl phosphate and aspartate. 2.fumarate is a product of the urea cycle. 3.3 ATP molecules (4 high energy bonds) are required per molecule of urea synthesized. 4.both transamination and oxidative deamination occur. A.Mark answer 'A' if statements 1, 2 and 3 are correct. B.Mark answer 'B' if statements 1 and 3 are correct. C.Mark answer 'C' if statements 2 and 4 are correct. D.Mark answer 'D' if ONLY statement 4 is correct. E.Mark answer 'E' if statements are ALL correct, or they are ALL incorrect. Tyrosine would be an essential amino acid in the diet of a child with 1.Lesch Nyhan Syndrome. 2.defective tyrosine aminotransferase. 3.a deficiency of pyridoxine.

4.classical phenylketonuria. A.Mark answer 'A' if statements 1, 2 and 3 are correct. B.Mark answer 'B' if statements 1 and 3 are correct. C.Mark answer 'C' if statements 2 and 4 are correct. D.Mark answer 'D' if ONLY statement 4 is correct. E.Mark answer 'E' if statements are ALL correct, or they are ALL incorrect. Which carbon atoms of heme are derived directly from 1.glycine. 2.histidine. 3.succinyl coenzyme A. 4.acetate. A.Mark answer 'A' if statements 1, 2 and 3 are correct. B.Mark answer 'B' if statements 1 and 3 are correct. C.Mark answer 'C' if statements 2 and 4 are correct. D.Mark answer 'D' if ONLY statement 4 is correct. E.Mark answer 'E' if statements are ALL correct, or they are ALL incorrect.