Question 1

Addition of pyrophosphate to which of the following occurs during the first step of purine biosynthesis?

Accepted Answer

A) 5-phosphoribosyl phosphate 
B) ribulose-5-phosphate 
C) ribose-5-phosphate 
D) ribose 
E) phosphribosylamine 
A) 5-phosphoribosyl phosphate 
B) ribulose-5-phosphate 
C) ribose-5-phosphate 
D) ribose 
E) phosphribosylamine

Question 2

The conversion of dUMP to dTMP by thymidylate synthase requires which of the following cofactors?
I.thioredoxin
II.N5,N10-methylenetetrahydrofolate
III.S-adenosylmethionine

Accepted Answer

A) I and II 
B) I only 
C) II only 
D) II and III 
E) I and III 
A) I and II 
B) I only 
C) II only 
D) II and III 
E) I and III

Question 3

Matching 
Choose the correct answer from the list. Not all the answers will be used.
-In purine synthesis the byproduct released when aspartate functions as an amino group donor is ________.

Accepted Answer

A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate 
A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate

Question 4

Matching 
Choose the correct answer from the list. Not all the answers will be used.
-Purines are degraded to ______.

Accepted Answer

A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate 
A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate

Question 5

The anticancer drug methotrexate inhibits nucleotide synthesis.Which of the following explains why it also inhibits the synthesis of histidine and methionine?

Accepted Answer

A) The synthetic pathways for these amino acids require tetrahydrofolate for group transfer reactions. 
B) These amino acids are derivatives of the nucleotides UTP and GTP. 
C) Without the synthesis of nucleotides, there is not sufficient energy for the synthesis of the amino acids. 
D) <ethotrexate inhibits also inhibits the precursors for these amino acids. 
E) all of the above 
A) The synthetic pathways for these amino acids require tetrahydrofolate for group transfer reactions. 
B) These amino acids are derivatives of the nucleotides UTP and GTP. 
C) Without the synthesis of nucleotides, there is not sufficient energy for the synthesis of the amino acids. 
D) <ethotrexate inhibits also inhibits the precursors for these amino acids. 
E) all of the above

Question 6

A final common product from both purine degradation and pyrimidine degradation is

Accepted Answer

A) uric acid. 
B) aspartate. 
C) ribose-1-phosphate. 
D) ribose-5-phosphate. 
E) malonyl-CoA. 
A) uric acid. 
B) aspartate. 
C) ribose-1-phosphate. 
D) ribose-5-phosphate. 
E) malonyl-CoA.

Question 7

The symptoms of Lesch-Nyhan syndrome are caused by a deficiency of which of the following enzymes?

Accepted Answer

A) adenine phosphoribosyltransferase 
B) HGPRT (hypoxanthine-guanine phosphoribosyltransferase) 
C) adenosine deaminase 
D) dihydrofolate reductase 
E) xanthine oxidase 
A) adenine phosphoribosyltransferase 
B) HGPRT (hypoxanthine-guanine phosphoribosyltransferase) 
C) adenosine deaminase 
D) dihydrofolate reductase 
E) xanthine oxidase

Question 8

The end products of pyrimidine catabolism are

Accepted Answer

A) uric acid and glyoxylic acid. 
B) uric acid and allantoin. 
C) ($\beta$-alanineand $\beta$-aminoisobutyrate.) 
D) ($\beta$-alanine and $\alpha$-ketoglutarate.) 
E) none of the above 
A) uric acid and glyoxylic acid. 
B) uric acid and allantoin. 
C) ($\beta$-alanineand $\beta$-aminoisobutyrate.) 
D) ($\beta$-alanine and $\alpha$-ketoglutarate.) 
E) none of the above

Question 9

Matching 
Choose the correct answer from the list. Not all the answers will be used.
-The precursor to AMP and GMP is ______.

Accepted Answer

A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate 
A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate

Question 10

Which best describes the synthesis of purine nucleotides?

Accepted Answer

A) The basic ring structure, orotate, is synthesized and then linked to PRPP.This is then modified to produce either GMP or AMP. 
B) The basic ring structure, inosine, is synthesized and then linked to PRPP.This is then modified to produce either GMP or AMP. 
C) The basic ring structure, orotate, is synthesized stepwise on PRPP.This is then modified to produce either GMP or AMP. 
D) The basic ring structure, inosine, is synthesized stepwise on PRPP.This is then modified to produce either GMP or AMP. 
E) The basic ring structure, orotate, is synthesized and then linked to PRPP.This is then modified to produce either UMP or CMP. 
A) The basic ring structure, orotate, is synthesized and then linked to PRPP.This is then modified to produce either GMP or AMP. 
B) The basic ring structure, inosine, is synthesized and then linked to PRPP.This is then modified to produce either GMP or AMP. 
C) The basic ring structure, orotate, is synthesized stepwise on PRPP.This is then modified to produce either GMP or AMP. 
D) The basic ring structure, inosine, is synthesized stepwise on PRPP.This is then modified to produce either GMP or AMP. 
E) The basic ring structure, orotate, is synthesized and then linked to PRPP.This is then modified to produce either UMP or CMP.

Question 11

The last step in purine degradation
I.generates hydrogen peroxide as a byproduct.
II.utilizes molecular oxygen.
III.is inhibited by methotrexate.
IV.requires NAD+.

Accepted Answer

A) I, II, III, IV 
B) I, II, IV 
C) II, IV 
D) I,  II, IV 
E) I, II 
A) I, II, III, IV 
B) I, II, IV 
C) II, IV 
D) I,  II, IV 
E) I, II

Question 12

Ribonecleotides   Using the diagram above, answer questions .C may be used to represent either or both of the atoms labeled C.
-Formate contributes to the ring at position _____.

Accepted Answer

A) A 
B) B 
C) D 
D) B, D 
E) F 
A) A 
B) B 
C) D 
D) B, D 
E) F

Question 13

Matching 
Choose the correct answer from the list. Not all the answers will be used.
-Class I ribonucleotide reductases (RNR)contain a(n)______ prosthetic group.

Accepted Answer

A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate 
A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate

Question 14

Matching 
Choose the correct answer from the list. Not all the answers will be used.
-Gout is treated using the compound ______.

Accepted Answer

A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate 
A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate

Question 15

Matching 
Choose the correct answer from the list. Not all the answers will be used.
-Mechanism-based inhibitors are also called _____ substrates.

Accepted Answer

A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate 
A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate

Question 16

Ribonecleotides   Using the diagram above, answer questions .C may be used to represent either or both of the atoms labeled C.
-Glycine contributes to the ring at position _____.

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 17

Matching 
Choose the correct answer from the list. Not all the answers will be used.
-During the turnover of nucleic acids some purines can be reincorporated into nucleotides via _____ pathways.

Accepted Answer

A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate 
A) fumarate 
B) NADPH 
C) salvage 
D) uric acid 
E) oxidation
F)XMP
G)iron
H)allopurinol
I)IMP
J)Oxidation
K)therapeutic
L)suicide
M)molybdenum
N)FADH
O)Malonyl-CoA
P)reduction
Q)antifolate

Question 18

The synthesis of 5-phosphoribosylamine from PRPP is
I.inhibited allosterically by ATP and GTP.
II.activated by PRPP via feed forward activation.
III.controlled by cAMP dependent phosphorylation.

Accepted Answer

A) I, II, III, 
B) I, II 
C) II, III 
D) II only 
E) III only 
A) I, II, III, 
B) I, II 
C) II, III 
D) II only 
E) III only

Question 19

Which of the following reactions is NOT catalyzed by nucleoside diphosphate kinase?

Accepted Answer

A) GDP + ATP $\rarr$ GTP + ADP 
B) UDP + ATP $\rarr$ UTP + ADP 
C) CDP + ATP $\rarr$ CTP + ADP 
D) dGDP + ATP $\rarr$ dGTP + ADP 
E) It catalyzes all the above. 
A) GDP + ATP $\rarr$ GTP + ADP 
B) UDP + ATP $\rarr$ UTP + ADP 
C) CDP + ATP $\rarr$ CTP + ADP 
D) dGDP + ATP $\rarr$ dGTP + ADP 
E) It catalyzes all the above.

Question 20

John Buchanan began the elucidation of the synthesis of purine nucleotides by studying _______ excreted by pigeons fed isotopically labeled compounds.

Accepted Answer

A) xanthine 
B) hypoxanthine 
C) uric acid 
D) ($\beta$-alanine) 
E) ($\beta$-aminoisobutyrate) 
A) xanthine 
B) hypoxanthine 
C) uric acid 
D) ($\beta$-alanine) 
E) ($\beta$-aminoisobutyrate)

Exam 23: Nucleotide Metabolism

Addition of pyrophosphate to which of the following occurs during the first step of purine biosynthesis?

The conversion of dUMP to dTMP by thymidylate synthase requires which of the following cofactors? I.thioredoxin II.N5,N10-methylenetetrahydrofolate III.S-adenosylmethionine

Matching Choose the correct answer from the list. Not all the answers will be used. -In purine synthesis the byproduct released when aspartate functions as an amino group donor is ________.

Matching Choose the correct answer from the list. Not all the answers will be used. -Purines are degraded to ______.

The anticancer drug methotrexate inhibits nucleotide synthesis.Which of the following explains why it also inhibits the synthesis of histidine and methionine?

A final common product from both purine degradation and pyrimidine degradation is

The symptoms of Lesch-Nyhan syndrome are caused by a deficiency of which of the following enzymes?

The end products of pyrimidine catabolism are

Matching Choose the correct answer from the list. Not all the answers will be used. -The precursor to AMP and GMP is ______.

Which best describes the synthesis of purine nucleotides?

The last step in purine degradation I.generates hydrogen peroxide as a byproduct. II.utilizes molecular oxygen. III.is inhibited by methotrexate. IV.requires NAD+.

Ribonecleotides Using the diagram above, answer questions .C may be used to represent either or both of the atoms labeled C. -Formate contributes to the ring at position _____.

Matching Choose the correct answer from the list. Not all the answers will be used. -Class I ribonucleotide reductases (RNR)contain a(n)______ prosthetic group.

Matching Choose the correct answer from the list. Not all the answers will be used. -Gout is treated using the compound ______.

Matching Choose the correct answer from the list. Not all the answers will be used. -Mechanism-based inhibitors are also called _____ substrates.

Ribonecleotides Using the diagram above, answer questions .C may be used to represent either or both of the atoms labeled C. -Glycine contributes to the ring at position _____.

Matching Choose the correct answer from the list. Not all the answers will be used. -During the turnover of nucleic acids some purines can be reincorporated into nucleotides via _____ pathways.

The synthesis of 5-phosphoribosylamine from PRPP is I.inhibited allosterically by ATP and GTP. II.activated by PRPP via feed forward activation. III.controlled by cAMP dependent phosphorylation.

Which of the following reactions is NOT catalyzed by nucleoside diphosphate kinase?

John Buchanan began the elucidation of the synthesis of purine nucleotides by studying _______ excreted by pigeons fed isotopically labeled compounds.

Introduction to the Chemistry of Life

Water

Nucleotides, Nucleic Acids, and Genetic Information

Amino Acids

Proteins: Primary Structure

Proteins: Three-Dimensional Structure

Protein Function Part I: Myoglobin and Hemoglobin

Carbohydrates

Lipids and Biological Membranes

Membrane Transport

Enzyme Catalysis

Enzyme Kinetics, Inhibition and Control

Biochemical Signaling

Introduction to Metabolism

Glycogen Metabolism and Gluconeogenesis

Glucose Catabolism

Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Mammalian Fuel Metabolism: Integration and Regulation

Nucleic Acid Structure

Dna Replication, Repair and Recombination

Transcription and Rna Processing

Translation

Regulation of Gene Expression

Filters

The conversion of dUMP to dTMP by thymidylate synthase requires which of the following cofactors? I.thioredoxin II.N⁵,N¹⁰-methylenetetrahydrofolate III.S-adenosylmethionine

The last step in purine degradation I.generates hydrogen peroxide as a byproduct. II.utilizes molecular oxygen. III.is inhibited by methotrexate. IV.requires NAD⁺.