Question 1

The enzyme _____ is missing in phenylketonuria while _____ is missing in alkaptonuria.

Accepted Answer

A)  tyrosine transaminase; phenylalanine hydroxylase 
B)  phenylalanine hydroxylase; p-hydroxy-phenylpyruvate dioxygenase 
C)  phenylalanine hydroxylase; homogentisate oxidase 
D)  p-hydroxy-phenylpyruvate dioxygenase; homogentisate oxidase 
E)  homogentisate oxidase; tyrosine transaminase 
A)  tyrosine transaminase; phenylalanine hydroxylase 
B)  phenylalanine hydroxylase; p-hydroxy-phenylpyruvate dioxygenase 
C)  phenylalanine hydroxylase; homogentisate oxidase 
D)  p-hydroxy-phenylpyruvate dioxygenase; homogentisate oxidase 
E)  homogentisate oxidase; tyrosine transaminase C

Question 2

What form of the folate coenzyme is required for the conversion of homocysteine to methionine?

Accepted Answer

A)  methyl-tetrahydrofolate 
B)  methylene-tetrahydrofolate 
C)  methenyl-tetrahydrofolate 
D)  formyl-tetrahydrofolate 
E)  dihydrofolate 
A)  methyl-tetrahydrofolate 
B)  methylene-tetrahydrofolate 
C)  methenyl-tetrahydrofolate 
D)  formyl-tetrahydrofolate 
E)  dihydrofolate A

Question 3

Threonine is considered both ketogenic and glucogenic because it is converted to _____ and _____.

Accepted Answer

A)  pyruvate; acetyl-CoA 
B)  ammonia; acetoacetate 
C)  carbamoyl phosphate; acetoacetate 
D)  glycine; acetyl-CoA 
E)  glycine; glutaryl-CoA 
A)  pyruvate; acetyl-CoA 
B)  ammonia; acetoacetate 
C)  carbamoyl phosphate; acetoacetate 
D)  glycine; acetyl-CoA 
E)  glycine; glutaryl-CoA D

Question 4

Which of the following amino acids cannot be produced in a plant that has been treated with glyphosate?

Accepted Answer

A)  Cys 
B)  Phe 
C)  Leu 
D)  Arg 
E)  Pro 
A)  Cys 
B)  Phe 
C)  Leu 
D)  Arg 
E)  Pro

Question 5

Which of the following are required by nitrogenase to carry out the reduction of nitrogen?

Accepted Answer

A)  an iron-molybdenum cofactor 
B)  iron-sulfur centers 
C)  a strong reducing agent such as ferredoxin 
D)  the absence of oxygen 
E)  all of the above 
A)  an iron-molybdenum cofactor 
B)  iron-sulfur centers 
C)  a strong reducing agent such as ferredoxin 
D)  the absence of oxygen 
E)  all of the above

Question 6

Which of the following amino acids is properly paired with the amino acid from which it is derived?

Accepted Answer

A)  Gln: Asp 
B)  Pro: Ala 
C)  Arg: Lys 
D)  Tyr: Phe 
E)  Ser: Cys 
A)  Gln: Asp 
B)  Pro: Ala 
C)  Arg: Lys 
D)  Tyr: Phe 
E)  Ser: Cys

Question 7

The molecule _____ which is synthesized from _____, stimulate vasodilation.

Accepted Answer

A)  nitric oxide; arginine 
B)  nitrous oxide; arginine 
C)  nitric oxide; citrulline 
D)  nitrous oxide; citrulline 
E)  none of the above 
A)  nitric oxide; arginine 
B)  nitrous oxide; arginine 
C)  nitric oxide; citrulline 
D)  nitrous oxide; citrulline 
E)  none of the above

Question 8

Which of the following correctly describes the general synthesis of purine nucleotides?

Accepted Answer

A)  The basic ring structure, orotate, is synthesized and then linked to PRPP 
B)  The basic ring structure, orotate, is synthesized stepwise on PRPP 
C)  The basic ring structure, inosine, is synthesized and then linked to PRPP 
D)  The basic ring structure, inosine, is synthesized stepwise on PRPP 
E)  none of the above 
A)  The basic ring structure, orotate, is synthesized and then linked to PRPP 
B)  The basic ring structure, orotate, is synthesized stepwise on PRPP 
C)  The basic ring structure, inosine, is synthesized and then linked to PRPP 
D)  The basic ring structure, inosine, is synthesized stepwise on PRPP 
E)  none of the above

Question 9

What amino acid is the precursor for the neurotransmitters epinephrine and norepinephrine?

Accepted Answer

A)  tryptophan 
B)  serine 
C)  tyrosine 
D)  aspartate 
E)  glutamate 
A)  tryptophan 
B)  serine 
C)  tyrosine 
D)  aspartate 
E)  glutamate

Question 10

Given the following reaction, what is the missing product of the net reaction of glutamine synthetase and glutamate synthase?
 $\alpha$ -ketoglutarate + NH4+ + NADPH + ATP $\rarr$  NADP+ + ADP + Pi + _____

Accepted Answer

A)  aspartate 
B)  asparagine 
C)  glutamate 
D)  glutamine 
E)  none of the above 
A)  aspartate 
B)  asparagine 
C)  glutamate 
D)  glutamine 
E)  none of the above

Question 11

Which of the following nonessential amino acids is correctly paired with the essential amino acid that is required for its synthesis?

Accepted Answer

A)  Phe: Trp 
B)  Cys: Met 
C)  Ser: Gly 
D)  Asp: Glu 
E)  His: Gln 
A)  Phe: Trp 
B)  Cys: Met 
C)  Ser: Gly 
D)  Asp: Glu 
E)  His: Gln

Question 12

What are the products of the following transamination reaction?
 $\alpha$ -ketoglutarate + alanine   _____ + _____

Accepted Answer

A)  aspartate; oxaloacetate 
B)  glutamate; oxaloacetate 
C)  aspartate; pyruvate 
D)  glutamate; pyruvate 
E)  none of the above 
A)  aspartate; oxaloacetate 
B)  glutamate; oxaloacetate 
C)  aspartate; pyruvate 
D)  glutamate; pyruvate 
E)  none of the above

Question 13

What are the products of the glycine cleavage system?

Accepted Answer

A)  formyl-tetrahydrofolate, ammonia and carbon dioxide 
B)  methylene-tetrahydrofolate, ammonia and carbon dioxide 
C)  methyl-tetrahydrofolate, ammonia and carbon dioxide 
D)  methylene-tetrahydrofolate and carbamoyl phosphate 
E)  methyl-tetrahydrofolate and carbamoyl phosphate 
A)  formyl-tetrahydrofolate, ammonia and carbon dioxide 
B)  methylene-tetrahydrofolate, ammonia and carbon dioxide 
C)  methyl-tetrahydrofolate, ammonia and carbon dioxide 
D)  methylene-tetrahydrofolate and carbamoyl phosphate 
E)  methyl-tetrahydrofolate and carbamoyl phosphate

Question 14

What coenzyme is required for the conversion of serine to glycine?

Accepted Answer

A)  pyridoxal phosphate 
B)  lipoic acid 
C)  tetrahydrofolate 
D)  biotin 
E)  cobalamin 
A)  pyridoxal phosphate 
B)  lipoic acid 
C)  tetrahydrofolate 
D)  biotin 
E)  cobalamin

Question 15

Which of the following neurotransmitters is correctly paired with the amino acid from which it is synthesized?

Accepted Answer

A)  dopamine: tyrosine 
B)   $\gamma$ -aminobutyric acid: glutamate 
C)  serotonin: tryptophan 
D)  epinephrine: tyrosine 
E)  all of the above 
A)  dopamine: tyrosine 
B)   $\gamma$ -aminobutyric acid: glutamate 
C)  serotonin: tryptophan 
D)  epinephrine: tyrosine 
E)  all of the above

Question 16

What amino acid is attached to the pyridoxal-5'-phosphate in a typical transaminase?

Accepted Answer

A)  Ser 
B)  His 
C)  Arg 
D)  Gln 
E)  Lys 
A)  Ser 
B)  His 
C)  Arg 
D)  Gln 
E)  Lys

Question 17

When the transaminase enzyme is in the _____ form, it will only react with _____.

Accepted Answer

A)  pyridoxal;  $\alpha$ -keto acid 
B)  pyridoxal;  $\alpha$ -amino acid 
C)  pyridoxamine;  $\alpha$ -amino acid 
D)  pyridoxal;  $\beta$ -keto acid 
E)  pyridoxamine;  $\beta$ -amino acid 
A)  pyridoxal;  $\alpha$ -keto acid 
B)  pyridoxal;  $\alpha$ -amino acid 
C)  pyridoxamine;  $\alpha$ -amino acid 
D)  pyridoxal;  $\beta$ -keto acid 
E)  pyridoxamine;  $\beta$ -amino acid

Question 18

Based upon the following, what is the net ATP production for the synthesis of one molecule of urea in the urea cycle? Consider that one nitrogen atom comes from glutamate dehydrogenase and the other comes from aspartate.
The conversion of fumarate to oxaloacetate gives 1 NADH (oxaloacetate is transaminated to aspartate)
Carbamoyl phosphate synthesis requires 2 ATP equivalents
Argininosuccinate synthesis requires 2 ATP equivalents
Glutamate dehydrogenase produces 1 NADH

Accepted Answer

A)  -4 ATP 
B)  -1.5 ATP 
C)  -1 ATP 
D)  +1 ATP 
E)  +3 ATP 
A)  -4 ATP 
B)  -1.5 ATP 
C)  -1 ATP 
D)  +1 ATP 
E)  +3 ATP

Question 19

How many ATP and electrons are required for the reduction of one molecule of nitrogen to two molecules of ammonia in the reaction catalyzed by nitrogenase?

Accepted Answer

A)  8 ATP and 8 electrons 
B)  16 ATP and 8 electrons 
C)  16 ATP and 16 electrons 
D)  8 ATP and 16 electrons 
E)  16 ATP and 6 electrons 
A)  8 ATP and 8 electrons 
B)  16 ATP and 8 electrons 
C)  16 ATP and 16 electrons 
D)  8 ATP and 16 electrons 
E)  16 ATP and 6 electrons

Question 20

The amino acids metabolized by the branched chain keto acid dehydrogenase complex are _____.

Accepted Answer

A)  Val, Leu and Ile 
B)  Thr, Val and Pro 
C)  Pro, Leu and Met 
D)  Ile, Thr and Pro 
E)  none of the above 
A)  Val, Leu and Ile 
B)  Thr, Val and Pro 
C)  Pro, Leu and Met 
D)  Ile, Thr and Pro 
E)  none of the above

Exam 18: Nitrogen Metabolism

The enzyme _____ is missing in phenylketonuria while _____ is missing in alkaptonuria.

What form of the folate coenzyme is required for the conversion of homocysteine to methionine?

Threonine is considered both ketogenic and glucogenic because it is converted to _____ and _____.

Which of the following amino acids cannot be produced in a plant that has been treated with glyphosate?

Which of the following are required by nitrogenase to carry out the reduction of nitrogen?

Which of the following amino acids is properly paired with the amino acid from which it is derived?

The molecule _____ which is synthesized from _____, stimulate vasodilation.

Which of the following correctly describes the general synthesis of purine nucleotides?

What amino acid is the precursor for the neurotransmitters epinephrine and norepinephrine?

Given the following reaction, what is the missing product of the net reaction of glutamine synthetase and glutamate synthase? α\alphaα -ketoglutarate + NH4+ + NADPH + ATP →\rarr→ NADP+ + ADP + Pi + _____

Which of the following nonessential amino acids is correctly paired with the essential amino acid that is required for its synthesis?

What are the products of the following transamination reaction? α\alphaα -ketoglutarate + alanine _____ + _____

What are the products of the glycine cleavage system?

What coenzyme is required for the conversion of serine to glycine?

Which of the following neurotransmitters is correctly paired with the amino acid from which it is synthesized?

What amino acid is attached to the pyridoxal-5'-phosphate in a typical transaminase?

When the transaminase enzyme is in the _____ form, it will only react with _____.

How many ATP and electrons are required for the reduction of one molecule of nitrogen to two molecules of ammonia in the reaction catalyzed by nitrogenase?

The amino acids metabolized by the branched chain keto acid dehydrogenase complex are _____.

The Chemical Basis of Life

Aqueous Chemistry

Nucleic Acid Structure and Function

Protein Structure

Protein Function

How Enzymes Work

Enzyme Kinetics and Inhibition

Lipids and Membranes

Membrane Transport

Signaling

Carbohydrates

Metabolism and Bioenergetics

Glucose Metabolism

The Citric Acid Cycle

Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Regulation of Mammalian Fuel Metabolism

DNA Replication and Repair

Transcription and RNA

Protein Synthesis

Filters

The enzyme _ is missing in phenylketonuria while _ is missing in alkaptonuria.

Threonine is considered both ketogenic and glucogenic because it is converted to _ and _.

The molecule _ which is synthesized from _, stimulate vasodilation.

Given the following reaction, what is the missing product of the net reaction of glutamine synthetase and glutamate synthase? $\alpha$ -ketoglutarate + NH₄⁺ + NADPH + ATP $\rarr$ NADP⁺ + ADP + P_i + _____

What are the products of the following transamination reaction? $\alpha$ -ketoglutarate + alanine $What are the products of the following transamination reaction? \alpha -ketoglutarate + alanine ___ + _$ _ + ___

When the transaminase enzyme is in the _ form, it will only react with _.