Question 1

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. D

Question 2

A large percentage of nitrogen,undergoing metabolism,comes from nitrogen fixation.

Accepted Answer

A) True 
 B)False  False

Question 3

In mammals,most amino acids undergo deamination in the ________.

Accepted Answer

A) liver 
B) kidney 
C) pancreas 
D) mitochondria of all cell types 
A) liver 
B) kidney 
C) pancreas 
D) mitochondria of all cell types A

Question 4

Malignant lymphocytes of patients with acute lymphoblastic leukemia can be treated with injections of bacterial asparaginase because

Accepted Answer

A) the levels of asparagine in malignant cells is too high. 
B) this reduces the levels of asparagine in blood plasma and that starves malignant cells. 
C) this increases the levels of asparagine in blood plasma and this promotes destruction of malignant cells. 
D) the levels of asparagine in malignant cells is too low. 
A) the levels of asparagine in malignant cells is too high. 
B) this reduces the levels of asparagine in blood plasma and that starves malignant cells. 
C) this increases the levels of asparagine in blood plasma and this promotes destruction of malignant cells. 
D) the levels of asparagine in malignant cells is too low.

Question 5

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 6

Nitrogenase catalyzes the reduction of N₂ to nitrate.

Accepted Answer

A) True 
 B)False

Question 7

What would be the product of the transamination of the structure shown below? (The unionized forms are shown. )

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
A) I 
B) II 
C) III 
D) IV

Question 8

Nitric oxide is produced from which reaction?

Accepted Answer

A) Arginine to citrulline. 
B) Glutamate to α-ketoglutarate. 
C) Bicarbonate to carbamoyl phosphate. 
D) Tryptophan to acetyl CoA. 
A) Arginine to citrulline. 
B) Glutamate to α-ketoglutarate. 
C) Bicarbonate to carbamoyl phosphate. 
D) Tryptophan to acetyl CoA.

Question 9

Glutamine is metabolised to biocarbonate ion in the ________ to replenish this important component of the blood buffering system.

Accepted Answer

A) liver 
B) kidneys 
C) red blood cells 
D) muscle tissue 
A) liver 
B) kidneys 
C) red blood cells 
D) muscle tissue

Question 10

Mammalian carbamoyl phosphate synthetase I

Accepted Answer

A) is one of the most abundant enzymes in liver mitochondria. 
B) is involved in the urea cycle. 
C) catalyzes the synthesis of carbamoyl phosphate from bicarbonate and ammonia. 
D) A and B only. 
E) All of the above. 
A) is one of the most abundant enzymes in liver mitochondria. 
B) is involved in the urea cycle. 
C) catalyzes the synthesis of carbamoyl phosphate from bicarbonate and ammonia. 
D) A and B only. 
E) All of the above.

Question 11

Which of these types of proteins are likely to have short half-life and be specifically targeted for degradation?

Accepted Answer

A) Hormone protein. 
B) Mutated (abnormal protein). 
C) Transport protein. 
D) Structural protein. 
A) Hormone protein. 
B) Mutated (abnormal protein). 
C) Transport protein. 
D) Structural protein.

Question 12

Microorganisms capable of fixing nitrogen into a form usable by animals obtain the energy for this process from ________.

Accepted Answer

A) lightning 
B) oxidation and reduction (respiration) 
C) photosynthesis of host plants 
D) soil nutrients 
A) lightning 
B) oxidation and reduction (respiration) 
C) photosynthesis of host plants 
D) soil nutrients

Question 13

Physiological roles for glutamate dehydrogenase include all of the following,except

Accepted Answer

A) the generation of glutamate when NH₄+ is present at high concentrations in E.coli. 
B) the conversion of glutamate to glutamine in most organisms. 
C) the use of an NADPH-dependent enzyme for reductive amination in Neurospora crassa. 
D) the degradation of amino acids and generation of NH₄+ in mammals. 
A) the generation of glutamate when NH₄+ is present at high concentrations in E.coli. 
B) the conversion of glutamate to glutamine in most organisms. 
C) the use of an NADPH-dependent enzyme for reductive amination in Neurospora crassa. 
D) the degradation of amino acids and generation of NH₄+ in mammals.

Question 14

Periportal cells of the liver are nearest to the inflow of blood and have a higher capacity for urea synthesis than the perivenous cells that are near the outflow.

Accepted Answer

A) True 
 B)False

Question 15

Industrially,nitrogen for use in fertilizers is converted to ammonia by ________.

Accepted Answer

A) a simple,energy efficient reaction of N₂ with water 
B) a cryogenic (very low temperature)process between N₂ and H₂ 
C) special catalysts which drive the reduction of N₂ by H₂ 
D) a reaction between nitric acid and hydrogen gas 
A) a simple,energy efficient reaction of N₂ with water 
B) a cryogenic (very low temperature)process between N₂ and H₂ 
C) special catalysts which drive the reduction of N₂ by H₂ 
D) a reaction between nitric acid and hydrogen gas

Question 16

In the urea cycle which molecule is transported from the mitochondrial matrix to the cytosol as ornithine is transported in the opposite direction?

Accepted Answer

A) Arginine. 
B) Citrulline. 
C) Glutamate. 
D) Carnitine. 
A) Arginine. 
B) Citrulline. 
C) Glutamate. 
D) Carnitine.

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

Defects in which of the following may result in elevated levels of phenylalanine?

Accepted Answer

A) Deficiencies in dihydropteridine reductase. 
B) Deficiencies in 4a-carbinolamine dehydratase. 
C) Defects in the biosynthesis of tetrahydrobiopterin. 
D) All of the above. 
A) Deficiencies in dihydropteridine reductase. 
B) Deficiencies in 4a-carbinolamine dehydratase. 
C) Defects in the biosynthesis of tetrahydrobiopterin. 
D) All of the above.

Question 19

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 20

Ammonia is incorporated into amino acids via which of the following?

Accepted Answer

A) Glutamate. 
B) Glutamine. 
C) Carbamoyl phosphate. 
D) All of the above. 
A) Glutamate. 
B) Glutamine. 
C) Carbamoyl phosphate. 
D) All of the above.

Exam 17: Amino Acid Metabolism

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

A large percentage of nitrogen,undergoing metabolism,comes from nitrogen fixation.

In mammals,most amino acids undergo deamination in the ________.

Malignant lymphocytes of patients with acute lymphoblastic leukemia can be treated with injections of bacterial asparaginase because

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

Nitrogenase catalyzes the reduction of N₂ to nitrate.

What would be the product of the transamination of the structure shown below? (The unionized forms are shown. )

Nitric oxide is produced from which reaction?

Glutamine is metabolised to biocarbonate ion in the ________ to replenish this important component of the blood buffering system.

Mammalian carbamoyl phosphate synthetase I

Which of these types of proteins are likely to have short half-life and be specifically targeted for degradation?

Microorganisms capable of fixing nitrogen into a form usable by animals obtain the energy for this process from ________.

Physiological roles for glutamate dehydrogenase include all of the following,except

Periportal cells of the liver are nearest to the inflow of blood and have a higher capacity for urea synthesis than the perivenous cells that are near the outflow.

Industrially,nitrogen for use in fertilizers is converted to ammonia by ________.

In the urea cycle which molecule is transported from the mitochondrial matrix to the cytosol as ornithine is transported in the opposite direction?

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

Defects in which of the following may result in elevated levels of phenylalanine?

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

Ammonia is incorporated into amino acids via which of the following?

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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