Question 1

The glucose-alanine cycle provides .

Accepted Answer

A)  an alternate site for production of urea in the kidney 
B)  transport of important enzymes for gluconeogenesis 
C)  an indirect means for muscle to eliminate nitrogen and replenish its energy supply 
D)  a cycle for the direct synthesis of carbohydrates in muscle 
A)  an alternate site for production of urea in the kidney 
B)  transport of important enzymes for gluconeogenesis 
C)  an indirect means for muscle to eliminate nitrogen and replenish its energy supply 
D)  a cycle for the direct synthesis of carbohydrates in muscle

Question 2

The disease alcaptonuria is caused by a defect in the kidney transport of cysteine.

Accepted Answer

A) True 
 B)False

Question 3

a-ketoglutarate is a precursor for each of the following, except

Accepted Answer

A)  glutamine. 
B)  arginine. 
C)  proline. 
D)  glycine. 
A)  glutamine. 
B)  arginine. 
C)  proline. 
D)  glycine.

Question 4

In mammals, ureogenesis occurs almost exclusively in the .

Accepted Answer

A)  liver 
B)  kidney 
C)  pancreas 
D)  lining of the small intestine 
A)  liver 
B)  kidney 
C)  pancreas 
D)  lining of the small intestine

Question 5

Nitric oxide functions as a neurotransmitter in the brain.

Accepted Answer

A) True 
 B)False

Question 6

Glutamate dehydrogenase has different roles in different organisms. Which of these listed is mismatched?

Accepted Answer

A)  E. coli bacterium) - generates NH4+ + glutamate 
B)  N. crassa fungus) - aminates a-ketoglutarate 
C)  mammals - degradation of amino acids and release of NH4+ 
D)  mammals - formation of glutamate 
A)  E. coli bacterium) - generates NH4+ + glutamate 
B)  N. crassa fungus) - aminates a-ketoglutarate 
C)  mammals - degradation of amino acids and release of NH4+ 
D)  mammals - formation of glutamate

Question 7

Which statement is false about protein turnover?

Accepted Answer

A)  The turnover rate is directly proportional to the stability of the proteinʹs tertiary structure. 
B)  Rapid turnover ensures that some regulatory proteins are degraded so that the cell can respond to changing conditions. 
C)  The half-life of a given protein is similar in different organs and species. 
D)  Turnover rates vary to give half-lives from a few minutes to several weeks. 
A)  The turnover rate is directly proportional to the stability of the proteinʹs tertiary structure. 
B)  Rapid turnover ensures that some regulatory proteins are degraded so that the cell can respond to changing conditions. 
C)  The half-life of a given protein is similar in different organs and species. 
D)  Turnover rates vary to give half-lives from a few minutes to several weeks.

Question 8

An amino acid formed by transamination of a citric acid cycle intermediate is .

Accepted Answer

A)  aspartate 
B)  cysteine 
C)  serine 
D)  alanine 
A)  aspartate 
B)  cysteine 
C)  serine 
D)  alanine

Question 9

The amino acids tyrosine and tryptophan are both ketogenic and glucogenic.

Accepted Answer

A) True 
 B)False

Question 10

At the subcellular level where does the urea cycle occur?

Accepted Answer

A)  mitochondrial matrix only 
B)  mitochondrial matrix and the mitochondrial inner membrane 
C)  mitochondrial matrix and the cytosol 
D)  cytosol only 
A)  mitochondrial matrix only 
B)  mitochondrial matrix and the mitochondrial inner membrane 
C)  mitochondrial matrix and the cytosol 
D)  cytosol only

Question 11

The degradation of arginine, histidine and proline all lead to the product .

Accepted Answer

A)  pyruvate 
B)  acetyl CoA 
C)  acetoacetate 
D)  glutamate 
A)  pyruvate 
B)  acetyl CoA 
C)  acetoacetate 
D)  glutamate

Question 12

In amino acid catabolism the α-amino groups are initially released as .

Accepted Answer

A)  nitrous oxide 
B)  ammonium ion 
C)  nitrate ion 
D)  glutamine 
A)  nitrous oxide 
B)  ammonium ion 
C)  nitrate ion 
D)  glutamine

Question 13

Which is not produced from the degradation of branched-chain amino acids?

Accepted Answer

A)  succinyl CoA 
B)  acetyl CoA 
C)  malonyl CoA 
D)  propionyl CoA 
A)  succinyl CoA 
B)  acetyl CoA 
C)  malonyl CoA 
D)  propionyl CoA

Question 14

Which disease is caused by a defect in ornithine transaminase activity?

Accepted Answer

A)  alcaptonuria 
B)  gyrate atrophy 
C)  cystinuria 
D)  maple syrup urine disease 
E)  nonketotic hyperglycinemia 
A)  alcaptonuria 
B)  gyrate atrophy 
C)  cystinuria 
D)  maple syrup urine disease 
E)  nonketotic hyperglycinemia

Question 15

Which of the following is an amide-containing amino acid?

Accepted Answer

A)  alanine 
B)  arginine 
C)  aspartate 
D)  asparagine 
A)  alanine 
B)  arginine 
C)  aspartate 
D)  asparagine

Question 16

Aspartate is the precursor for which of the following amino acids?

Accepted Answer

A)  lysine 
B)  threonine 
C)  methionine 
D)  All of the above 
A)  lysine 
B)  threonine 
C)  methionine 
D)  All of the above

Question 17

A patient is experiencing uncontrolled diabetes mellitus with an overproduction of β-hydroxybutyric acid. Which statement is false?

Accepted Answer

A)  The patient will exhale extra amounts of carbon dioxide. 
B)  Glutamine will be catabolized to reform lost bicarbonate ion. 
C)  The basic amino acids, lysine and arginine, neutralize the β-hydroxybutyric acid in the blood. 
D)  The anion of β-hydroxybutyric acid will be excreted in the urine. 
A)  The patient will exhale extra amounts of carbon dioxide. 
B)  Glutamine will be catabolized to reform lost bicarbonate ion. 
C)  The basic amino acids, lysine and arginine, neutralize the β-hydroxybutyric acid in the blood. 
D)  The anion of β-hydroxybutyric acid will be excreted in the urine.

Question 18

Nitric oxide is formed from arginine. It is a messenger molecule with several functions that include all below except

Accepted Answer

A)  macrophage activation. 
B)  reacting with superoxide anions to form more toxic substances. 
C)  constricting red blood cells. 
D)  neurotransmitter in the brain. 
A)  macrophage activation. 
B)  reacting with superoxide anions to form more toxic substances. 
C)  constricting red blood cells. 
D)  neurotransmitter in the brain.

Question 19

Amino acids that are degraded to pyruvate or citric acid cycle intermediates are called ketogenic.

Accepted Answer

A) True 
 B)False

Question 20

The essential amino acids are those that mammals cannot synthesize, but must obtain from the diet.

Accepted Answer

A) True 
 B)False

Exam 17: Amino Acid Metabolism

The glucose-alanine cycle provides .

The disease alcaptonuria is caused by a defect in the kidney transport of cysteine.

a-ketoglutarate is a precursor for each of the following, except

In mammals, ureogenesis occurs almost exclusively in the .

Nitric oxide functions as a neurotransmitter in the brain.

Glutamate dehydrogenase has different roles in different organisms. Which of these listed is mismatched?

Which statement is false about protein turnover?

An amino acid formed by transamination of a citric acid cycle intermediate is .

The amino acids tyrosine and tryptophan are both ketogenic and glucogenic.

At the subcellular level where does the urea cycle occur?

The degradation of arginine, histidine and proline all lead to the product .

In amino acid catabolism the α-amino groups are initially released as .

Which is not produced from the degradation of branched-chain amino acids?

Which disease is caused by a defect in ornithine transaminase activity?

Which of the following is an amide-containing amino acid?

Aspartate is the precursor for which of the following amino acids?

A patient is experiencing uncontrolled diabetes mellitus with an overproduction of β-hydroxybutyric acid. Which statement is false?

Nitric oxide is formed from arginine. It is a messenger molecule with several functions that include all below except

Amino acids that are degraded to pyruvate or citric acid cycle intermediates are called ketogenic.

The essential amino acids are those that mammals cannot synthesize, but must obtain from the diet.

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

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