Question 1

A coenzyme frequently encountered in transamination reactions is

Accepted Answer

A)  tetrahydrofolate 
B)  pyridoxal phosphate 
C)  thiamine pyrophosphate 
D)  biotin 
A)  tetrahydrofolate 
B)  pyridoxal phosphate 
C)  thiamine pyrophosphate 
D)  biotin

Question 2

The term ketogenic amino acids refers to amino acids

Accepted Answer

A)  that are precursors for glucose synthesis. 
B)  that are degraded to yield acetyl CoA or acetoacetate 
C)  that can not be converted to fatty acids or ketone bodies. 
D)  that are degraded to yield succinyl-CoA, pyruvate, α-ketoglutarate, fumarate and oxaloacetate. 
E)  None of these. 
A)  that are precursors for glucose synthesis. 
B)  that are degraded to yield acetyl CoA or acetoacetate 
C)  that can not be converted to fatty acids or ketone bodies. 
D)  that are degraded to yield succinyl-CoA, pyruvate, α-ketoglutarate, fumarate and oxaloacetate. 
E)  None of these.

Question 3

The carbon skeletons of specific amino acids cannot be used to replenish which of the following species associated with the citric acid cycle?

Accepted Answer

A)  pyruvate 
B)  citrate 
C)  fumarate 
D)  succinyl CoA 
E)  all of these can be used 
A)  pyruvate 
B)  citrate 
C)  fumarate 
D)  succinyl CoA 
E)  all of these can be used

Question 4

All of the following are metabolic intermediates of α-amino acid carbon skeletons except:

Accepted Answer

A)  pyridoxine 
B)  α-ketoglutarate 
C)  oxaloacetate 
D)  succinyl-CoA 
E)  fumarate 
A)  pyridoxine 
B)  α-ketoglutarate 
C)  oxaloacetate 
D)  succinyl-CoA 
E)  fumarate

Question 5

The two nitrogens in urea arise directly from:

Accepted Answer

A)  Ammonia and aspartic acid 
B)  Carbamoyl phosphate and glutamic acid 
C)  Ammonia and glutamic acid 
D)  Carbamoyl phosphate and glutamine 
A)  Ammonia and aspartic acid 
B)  Carbamoyl phosphate and glutamic acid 
C)  Ammonia and glutamic acid 
D)  Carbamoyl phosphate and glutamine

Question 6

Write a mechanism for the formation of α-iminoglutarate from glutamate employing NAD+ as the oxidizing coenzyme.

Accepted Answer

Question 7

The appropriate sequence in the biosynthesis of proline from glutamate is: 1.NADPH reduction and release of Pi
2)Dehydration to 1-pyrroline-5-carboxylate
3)NADPH reduction of Schiff base
4)Phosphorylation to glutamate-5-phosphate

Accepted Answer

A)  4, 2, 1, 3 
B)  4, 1, 2, 3 
C)  1, 4, 3, 2 
D)  1, 4, 2, 3 
E)  2, 3, 1, 4 
A)  4, 2, 1, 3 
B)  4, 1, 2, 3 
C)  1, 4, 3, 2 
D)  1, 4, 2, 3 
E)  2, 3, 1, 4

Question 8

Many biological reactions are endergonic. Explain how it is possible that these reactions occur spontaneously.

Accepted Answer

Endergonic reactions such as the convers

Question 9

By a simple transamination reaction, intermediates in the Citric Acid Cycle can be converted in one step to all of these amino acids, except:

Accepted Answer

A)  Alanine 
B)  Aspartic acid 
C)  Glutamic acid 
D)  Cysteine 
E)  All of these amino acids are only one step away from the major metabolic pathways. 
A)  Alanine 
B)  Aspartic acid 
C)  Glutamic acid 
D)  Cysteine 
E)  All of these amino acids are only one step away from the major metabolic pathways.

Question 10

All of the following are true of transamination except:

Accepted Answer

A)  It is characterized by the transfer of an α-amino group from an amino acid to the α-keto position of an α-keto acid. 
B)  The amino donor becomes an α-keto acid. 
C)  The coenzyme needed is thiamine diphosphate. 
D)  The α-keto acid acceptor becomes an α-amino acid. 
A)  It is characterized by the transfer of an α-amino group from an amino acid to the α-keto position of an α-keto acid. 
B)  The amino donor becomes an α-keto acid. 
C)  The coenzyme needed is thiamine diphosphate. 
D)  The α-keto acid acceptor becomes an α-amino acid.

Question 11

The carbon chains of amino acids enter the major metabolic pathways through all of these compounds, except:

Accepted Answer

A)  α-ketoglutarate 
B)  Pyruvate 
C)  Glyceraldehyde 
D)  Acetyl CoA 
E)  All of these are entry points for amino acid catabolism. 
A)  α-ketoglutarate 
B)  Pyruvate 
C)  Glyceraldehyde 
D)  Acetyl CoA 
E)  All of these are entry points for amino acid catabolism.

Question 12

Transamination of pyruvate with glutamate as the nitrogen donor gives:

Accepted Answer

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

A coenzyme frequently encountered in transamination reactions is

The term ketogenic amino acids refers to amino acids

The carbon skeletons of specific amino acids cannot be used to replenish which of the following species associated with the citric acid cycle?

All of the following are metabolic intermediates of α-amino acid carbon skeletons except:

The two nitrogens in urea arise directly from:

Write a mechanism for the formation of α-iminoglutarate from glutamate employing NAD⁺ as the oxidizing coenzyme.

The appropriate sequence in the biosynthesis of proline from glutamate is: 1.NADPH reduction and release of P_i 2)Dehydration to 1-pyrroline-5-carboxylate 3)NADPH reduction of Schiff base 4)Phosphorylation to glutamate-5-phosphate

Many biological reactions are endergonic. Explain how it is possible that these reactions occur spontaneously.

By a simple transamination reaction, intermediates in the Citric Acid Cycle can be converted in one step to all of these amino acids, except:

All of the following are true of transamination except:

The carbon chains of amino acids enter the major metabolic pathways through all of these compounds, except:

Transamination of pyruvate with glutamate as the nitrogen donor gives:

Structure and Bonding

Polar Covalent Bonds; Acids and Bases

Organic Compounds: Alkanes and Their Stereochemistry

Organic Compounds: Cycloalkanes and Their Stereochemistry

Stereochemistry at Tetrahedral Centers

An Overview of Organic Reactions

Alkenes and Alkynes

Reactions of Alkenes and Alkynes

Aromatic Compounds

Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy

Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy

Structure Determination: Nuclear Magnetic Resonance Spectroscopy

Organohalides: Nucleophilic Substitutions and Eliminations

Alcohols, Phenols, and Thiols; Ethers and Sulfides

Aldehydes and Ketones: Nucleophilic Addition Reactions

Carboxylic Acids and Nitriles

Carboxylic Acid Derivatives: Nucleophilic Acyl Substitution Reactions

Carbonyl Alpha-Substitution and Condensation Reactions

Amines and Heterocycles

Biomolecules: Amino Acids, Peptides, and Proteins

Biomolecules: Carbohydrates

Carbohydrate Metabolism

Biomolecules: Lipids and Their Metabolism

Biomolecules: Nucleic Acids and Their Metabolism

Orbitals and Organic Chemistry: Pericyclic Reactionse

Synthetic Polymerse

Filters

Exam 20: Amino Acid Metabolism

A coenzyme frequently encountered in transamination reactions is

The term ketogenic amino acids refers to amino acids

The carbon skeletons of specific amino acids cannot be used to replenish which of the following species associated with the citric acid cycle?

All of the following are metabolic intermediates of α-amino acid carbon skeletons except:

The two nitrogens in urea arise directly from:

Write a mechanism for the formation of α-iminoglutarate from glutamate employing NAD+ as the oxidizing coenzyme.

The appropriate sequence in the biosynthesis of proline from glutamate is: 1.NADPH reduction and release of Pi 2)Dehydration to 1-pyrroline-5-carboxylate 3)NADPH reduction of Schiff base 4)Phosphorylation to glutamate-5-phosphate

Many biological reactions are endergonic. Explain how it is possible that these reactions occur spontaneously.

By a simple transamination reaction, intermediates in the Citric Acid Cycle can be converted in one step to all of these amino acids, except:

All of the following are true of transamination except:

The carbon chains of amino acids enter the major metabolic pathways through all of these compounds, except:

Transamination of pyruvate with glutamate as the nitrogen donor gives:

Structure and Bonding

Polar Covalent Bonds; Acids and Bases

Organic Compounds: Alkanes and Their Stereochemistry

Organic Compounds: Cycloalkanes and Their Stereochemistry

Stereochemistry at Tetrahedral Centers

An Overview of Organic Reactions

Alkenes and Alkynes

Reactions of Alkenes and Alkynes

Aromatic Compounds

Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy

Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy

Structure Determination: Nuclear Magnetic Resonance Spectroscopy

Organohalides: Nucleophilic Substitutions and Eliminations

Alcohols, Phenols, and Thiols; Ethers and Sulfides

Aldehydes and Ketones: Nucleophilic Addition Reactions

Carboxylic Acids and Nitriles

Carboxylic Acid Derivatives: Nucleophilic Acyl Substitution Reactions

Carbonyl Alpha-Substitution and Condensation Reactions

Amines and Heterocycles

Biomolecules: Amino Acids, Peptides, and Proteins

Biomolecules: Carbohydrates

Carbohydrate Metabolism

Biomolecules: Lipids and Their Metabolism

Biomolecules: Nucleic Acids and Their Metabolism

Orbitals and Organic Chemistry: Pericyclic Reactionse

Synthetic Polymerse

Filters

Write a mechanism for the formation of α-iminoglutarate from glutamate employing NAD⁺ as the oxidizing coenzyme.

The appropriate sequence in the biosynthesis of proline from glutamate is: 1.NADPH reduction and release of P_i 2)Dehydration to 1-pyrroline-5-carboxylate 3)NADPH reduction of Schiff base 4)Phosphorylation to glutamate-5-phosphate