Question 1

Which of the following is the final degradation product of purine catabolism?

Accepted Answer

A)  xanthine 
B)  hypoxanthine 
C)  inosine 
D)  urate 
E)  None of the answers is correct. 
A)  xanthine 
B)  hypoxanthine 
C)  inosine 
D)  urate 
E)  None of the answers is correct.

Question 2

The ultimate reductant in synthesis of deoxyribonucleotides is

Accepted Answer

A)  FADH2. 
B)  NADH. 
C)  NADPH. 
D)  quinine. 
E)  None of the answers is correct. 
A)  FADH2. 
B)  NADH. 
C)  NADPH. 
D)  quinine. 
E)  None of the answers is correct.

Question 3

Which of the following is a competitive inhibitor of dihydrofolate reductase that is effective for anticancer chemotherapy?

Accepted Answer

A)  aminopterin 
B)  methotrexate 
C)  fluorouracil 
D)  trimethoprim 
E)  aminopterin and methotrexate 
A)  aminopterin 
B)  methotrexate 
C)  fluorouracil 
D)  trimethoprim 
E)  aminopterin and methotrexate

Question 4

What disease is caused by high levels of urate?

Accepted Answer

A)  severe combined immunodeficiency 
B)  Lesch-Nyhan syndrome 
C)  gout 
D)  spina bifida 
E)  None of the answers is correct. 
A)  severe combined immunodeficiency 
B)  Lesch-Nyhan syndrome 
C)  gout 
D)  spina bifida 
E)  None of the answers is correct.

Question 5

Why is nucleotide synthesis an important pathway for medical intervention? What types of disease could be treated using this information?

Accepted Answer

Interference with nucleotide synthesis c

Question 6

How is the reciprocal use of nucleotides useful in purine synthesis?

Accepted Answer

AMP synthesis requires GTP,whe

Question 7

Which amino acid side chain in thymidylate synthase activates the ring of dUMP,making C-5 a good nucleophile?

Accepted Answer

A)  cysteine 
B)  aspartate 
C)  glutamine 
D)  tyrosine 
E)  serine 
A)  cysteine 
B)  aspartate 
C)  glutamine 
D)  tyrosine 
E)  serine

Question 8

Which enzyme(s),in nucleotide biosynthesis pathways,use(s)a substrate channeling mechanism?

Accepted Answer

A)  carbamoyl phosphate synthetase 
B)  nucleoside monophosphate kinase 
C)  glutamine phosphoribosyl amidotransferase 
D)  aspartate transcarbamoylase 
E)  carbamoyl phosphate synthetase and glutamine phosphoribosyl amidotransferase 
A)  carbamoyl phosphate synthetase 
B)  nucleoside monophosphate kinase 
C)  glutamine phosphoribosyl amidotransferase 
D)  aspartate transcarbamoylase 
E)  carbamoyl phosphate synthetase and glutamine phosphoribosyl amidotransferase

Question 9

Tetrahydrofolate is generated from dihydrofolate by dihydrofolate reductase and uses the reductant

Accepted Answer

A)  FADH2. 
B)  NADH. 
C)  NADPH. 
D)  riboflavin. 
E)  None of the answers is correct. 
A)  FADH2. 
B)  NADH. 
C)  NADPH. 
D)  riboflavin. 
E)  None of the answers is correct.

Question 10

Which nucleotide is most commonly used as an energy currency?

Accepted Answer

A)  ATP 
B)  UTP 
C)  GTP 
D)  CTP 
E)  TTP 
A)  ATP 
B)  UTP 
C)  GTP 
D)  CTP 
E)  TTP

Exam 25: Nucleotide Biosynthesis

Which of the following is the final degradation product of purine catabolism?

The ultimate reductant in synthesis of deoxyribonucleotides is

Which of the following is a competitive inhibitor of dihydrofolate reductase that is effective for anticancer chemotherapy?

What disease is caused by high levels of urate?

Why is nucleotide synthesis an important pathway for medical intervention? What types of disease could be treated using this information?

How is the reciprocal use of nucleotides useful in purine synthesis?

Which amino acid side chain in thymidylate synthase activates the ring of dUMP,making C-5 a good nucleophile?

Which enzyme(s),in nucleotide biosynthesis pathways,use(s)a substrate channeling mechanism?

Tetrahydrofolate is generated from dihydrofolate by dihydrofolate reductase and uses the reductant

Which nucleotide is most commonly used as an energy currency?

Biochemistry: An Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Membrane Channels and Pumps

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

Oxidative Phosphorylation

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

DNA Replication, repair, and Recombination

RNA Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

Drug Development

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