Question 1

What is significant about the fact that E.coli ribonucleotide reductase contains two allosteric sites?

Accepted Answer

One of the sites controls the overall activity of the enzyme, and the other regulates substrate specificity. This complex pattern of regulation supplies the appropriate balance of the four deoxyribonucleotides needed for synthesis of DNA.

Question 2

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. D

Question 3

What reaction actually forms the six-member ring found in pyrimidines?

Accepted Answer

The reaction between carbamoyl phosphate and aspartate forms a chain, with a terminal nitrogen poised near a carboxylic acid group. These groups react and cyclization results in dihydroorotate formation.

Question 4

Hypoxanthine-guanine phosphoribosyltransferase catalyzes the formation of guanylate and _______________.

Accepted Answer

The answer of Hypoxanthine-guanine phosphoribosyltransferase catalyzes the formation of guanylate...

Question 5

Amination of _____ produces CTP.

Accepted Answer

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

Question 6

Assembly of a nucleoside from PRPP and a pre-existing base is known as a(n) _____ pathway.

Accepted Answer

A)  salvage 
B)  synthetic 
C)  catabolic 
D)  anabolic 
E)  de novo 
A)  salvage 
B)  synthetic 
C)  catabolic 
D)  anabolic 
E)  de novo

Question 7

Some individuals with a deficiency in the enzyme adenosine deaminase exhibit _______________ (bubble boy disease).

Accepted Answer

severe com

Question 8

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 9

A purine or pyrimidine base linked to a sugar is a _____.

Accepted Answer

A)  nucleotide 
B)  nucleoside 
C)  ribonucleotide 
D)  deoxynucleotide 
E)  None of the answers is correct. 
A)  nucleotide 
B)  nucleoside 
C)  ribonucleotide 
D)  deoxynucleotide 
E)  None of the answers is correct.

Question 10

What is an ATP-grasp fold?

Accepted Answer

This is a protein domain that binds ATP

Question 11

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 12

The committed step in purine nucleotide biosynthesis is the conversion of _______________ to phosphoribosylamine.

Accepted Answer

The answer of The committed step in purine nucleotide biosynthesis...

Question 13

In addition to UTP, the synthesis of CTP from UTP requires __________

Accepted Answer

A)  glutamine and ATP. 
B)  glycine and ATP. 
C)  glutamine, ATP, and NADH. 
D)  glycine and TTP. 
E)  None of the answers is correct. 
A)  glutamine and ATP. 
B)  glycine and ATP. 
C)  glutamine, ATP, and NADH. 
D)  glycine and TTP. 
E)  None of the answers is correct.

Question 14

The conversion of ribonucleotides to deoxyribonucleotides is catalyzed by ________________.

Accepted Answer

ribonucleo

Question 15

What is the intermediate in the conversion of inosinate to guanylate?

Accepted Answer

A)  adenylate 
B)  cytidylate 
C)  guanylate 
D)  orotidylate 
E)  xanthylate 
A)  adenylate 
B)  cytidylate 
C)  guanylate 
D)  orotidylate 
E)  xanthylate

Question 16

TMP is made from

Accepted Answer

A)  dTMP. 
B)  UTP. 
C)  CTP. 
D)  ATP. 
E)  None of the answers is correct. 
A)  dTMP. 
B)  UTP. 
C)  CTP. 
D)  ATP. 
E)  None of the answers is correct.

Question 17

Which of the following is decarboxylated to form uridylate?

Accepted Answer

A)  adenylate 
B)  cytidylate 
C)  guanylate 
D)  orotidylate 
E)  None of the answers is correct. 
A)  adenylate 
B)  cytidylate 
C)  guanylate 
D)  orotidylate 
E)  None of the answers is correct.

Question 18

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 19

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

Question 20

In ______________ biosynthesis, the base is assembled first and then attached to ribose.

Accepted Answer

The answer of In ______________ biosynthesis, the base is assembled...

Exam 25: Nucleotide Biosynthesis

What is significant about the fact that E.coli ribonucleotide reductase contains two allosteric sites?

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

What reaction actually forms the six-member ring found in pyrimidines?

Hypoxanthine-guanine phosphoribosyltransferase catalyzes the formation of guanylate and _______________.

Amination of _____ produces CTP.

Assembly of a nucleoside from PRPP and a pre-existing base is known as a(n) _____ pathway.

Some individuals with a deficiency in the enzyme adenosine deaminase exhibit _______________ (bubble boy disease).

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

A purine or pyrimidine base linked to a sugar is a _____.

What is an ATP-grasp fold?

What disease is caused by high levels of urate?

The committed step in purine nucleotide biosynthesis is the conversion of _______________ to phosphoribosylamine.

In addition to UTP, the synthesis of CTP from UTP requires __________

The conversion of ribonucleotides to deoxyribonucleotides is catalyzed by ________________.

What is the intermediate in the conversion of inosinate to guanylate?

TMP is made from

Which of the following is decarboxylated to form uridylate?

The ultimate reductant in synthesis of deoxyribonucleotides is

Which nucleotide is most commonly used as an energy currency?

In ______________ biosynthesis, the base is assembled first and then attached to ribose.

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

Oxidative Phosphorylation

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

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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