Question 1

Chorismate is a key branch-point intermediate in aromatic amino acid synthesis.

Accepted Answer

A) True 
 B)False

Question 2

The changes that occur in cells that lead to its death are called ________.

Accepted Answer

A) cellular necroptosis 
B) programmed lysis 
C) apoptosis 
D) morpholytic degradation 
A) cellular necroptosis 
B) programmed lysis 
C) apoptosis 
D) morpholytic degradation

Question 3

Nitrogenases

Accepted Answer

A) are protected from oxygen to prevent inactivation. 
B) consist of two protein components. 
C) contain an electron transport system. 
D) A and B only. 
E) All of the above. 
A) are protected from oxygen to prevent inactivation. 
B) consist of two protein components. 
C) contain an electron transport system. 
D) A and B only. 
E) All of the above.

Question 4

The catabolism of which amino acids can produce sulfuric acid?

Accepted Answer

A) cysteine and methionine 
B) cysteine and serine 
C) aspartate and glutamate 
D) lysine and arginine 
A) cysteine and methionine 
B) cysteine and serine 
C) aspartate and glutamate 
D) lysine and arginine

Question 5

Which of the following is/are true statement(s)about glutamine?

Accepted Answer

A) It is a nitrogen donor in many biosynthetic reactions. 
B) It is a nitrogen source for glutamate synthase. 
C) It carries nitrogen and carbon between tissues,thus avoiding high toxic levels of NH₄+ in blood. 
D) All of the above. 
A) It is a nitrogen donor in many biosynthetic reactions. 
B) It is a nitrogen source for glutamate synthase. 
C) It carries nitrogen and carbon between tissues,thus avoiding high toxic levels of NH₄+ in blood. 
D) All of the above.

Question 6

What type of reaction is shown below? Amino acid + α-Ketoglutarate⇋ α-Keto acid + Glutamate

Accepted Answer

A) Reductive amination. 
B) Oxidation. 
C) Transamination. 
D) Hydrolysis. 
A) Reductive amination. 
B) Oxidation. 
C) Transamination. 
D) Hydrolysis.

Question 7

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

Accepted Answer

A) True 
 B)False

Question 8

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 9

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 10

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

Accepted Answer

A) True 
 B)False

Question 11

Most animals and plants can tolerate moderately high cellular concentrations of ammonia;however,unusable excess is generally eliminated via the urea cycle.

Accepted Answer

A) True 
 B)False

Question 12

At neutral pH,the main ionic form of ammonia is ________.

Accepted Answer

A) N₂ 
B) NH₄+ 
C) NH₃ 
D) NH₂- 
E) None of the above 
A) N₂ 
B) NH₄+ 
C) NH₃ 
D) NH₂- 
E) None of the above

Question 13

During the catabolism of amino acids,the carbon skeleton is first degraded,followed by the removal of the amino group.

Accepted Answer

A) True 
 B)False

Question 14

Most green plants contain both nitrate reductase and nitrite reductase to reduce nitrogen oxides to ammonia.

Accepted Answer

A) True 
 B)False

Question 15

Transamination reactions require which coenzyme?

Accepted Answer

A) Pyridoxal phosphate. 
B) Thiamine pyrophosphate. 
C) Adensosine triphosphate. 
D) Flavin mononucleotide. 
A) Pyridoxal phosphate. 
B) Thiamine pyrophosphate. 
C) Adensosine triphosphate. 
D) Flavin mononucleotide.

Question 16

Tryptophan synthase's a subunit catalyzes the cleavage of indole glycerol phosphate to glyceralde 3-phosphate and indole.

Accepted Answer

A) True 
 B)False

Question 17

The enzyme ________ is one of the most abundant in liver mitochondria and catalyzes the synthesis of the molecule shown below.

Accepted Answer

A) arginase 
B) carbamoyl phosphate synthetase I 
C) 4-α-carbinolamine dehydratase 
D) transaminase 
A) arginase 
B) carbamoyl phosphate synthetase I 
C) 4-α-carbinolamine dehydratase 
D) transaminase

Question 18

Protein turnover of regulatory proteins helps cells to quickly respond to changing conditions.

Accepted Answer

A) True 
 B)False

Question 19

A key precursor in the synthesis of aromatic amino acids (tryptophan,tyrosine and phenylalanine)is ________.

Accepted Answer

A) prephenate 
B) chorismate 
C) 4-hydroxyphenylpyruvate 
D) indole 
A) prephenate 
B) chorismate 
C) 4-hydroxyphenylpyruvate 
D) indole

Question 20

Which of the following is/are true concerning transanimation reactions?

Accepted Answer

A) They can convert α-keto acids to α-amino acids. 
B) All require the coenzyme pyridoxal phosphate. 
C) The catalyzed reactions are near-equilibrium. 
D) All of the above. 
A) They can convert α-keto acids to α-amino acids. 
B) All require the coenzyme pyridoxal phosphate. 
C) The catalyzed reactions are near-equilibrium. 
D) All of the above.

Exam 17: Amino Acid Metabolism

Chorismate is a key branch-point intermediate in aromatic amino acid synthesis.

The changes that occur in cells that lead to its death are called ________.

Nitrogenases

The catabolism of which amino acids can produce sulfuric acid?

Which of the following is/are true statement(s)about glutamine?

What type of reaction is shown below? Amino acid + α-Ketoglutarate⇋ α-Keto acid + Glutamate

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

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

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

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

Most animals and plants can tolerate moderately high cellular concentrations of ammonia;however,unusable excess is generally eliminated via the urea cycle.

At neutral pH,the main ionic form of ammonia is ________.

During the catabolism of amino acids,the carbon skeleton is first degraded,followed by the removal of the amino group.

Most green plants contain both nitrate reductase and nitrite reductase to reduce nitrogen oxides to ammonia.

Transamination reactions require which coenzyme?

Tryptophan synthase's a subunit catalyzes the cleavage of indole glycerol phosphate to glyceralde 3-phosphate and indole.

The enzyme ________ is one of the most abundant in liver mitochondria and catalyzes the synthesis of the molecule shown below.

Protein turnover of regulatory proteins helps cells to quickly respond to changing conditions.

A key precursor in the synthesis of aromatic amino acids (tryptophan,tyrosine and phenylalanine)is ________.

Which of the following is/are true concerning transanimation reactions?

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 Atp Synthesis

Photosynthesis

Lipid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

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