Question 1

Isoleucine, leucine and valine are all formed from the same amino acid root, aspartic acid.

Accepted Answer

A) True 
 B)False

Question 2

If an amino acid is ketogenic, then it:

Accepted Answer

A)  has a catabolic pathway that leads to acetyl-CoA or acetoacetyl-CoA 
B)  has a one step pathway to a fatty acid 
C)  enters the citric acid cycle as pyruvate 
D)  enters the citric acid cycle as fumarate 
E)  none of these 
A)  has a catabolic pathway that leads to acetyl-CoA or acetoacetyl-CoA 
B)  has a one step pathway to a fatty acid 
C)  enters the citric acid cycle as pyruvate 
D)  enters the citric acid cycle as fumarate 
E)  none of these

Question 3

What intermediate of the TCA cycle is produced from aspartic acid during the urea cycle, synthesis of IMP, and conversion from IMP to adenosine?

Accepted Answer

A)  fumarate 
B)  malate 
C)  α -ketoglutarate 
D)  succinate 
A)  fumarate 
B)  malate 
C)  α -ketoglutarate 
D)  succinate

Question 4

Which of the following compounds does not serve as an intermediate for the entry of amino acid carbon chains into the major metabolic pathways?

Accepted Answer

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

Question 5

The conversion of glutamate to glutamine is catalyzed by glutamine synthetase and requires ATP.

Accepted Answer

A) True 
 B)False

Question 6

Pyridoxal phosphate is involved in which of the following reactions?

Accepted Answer

A)  transaminations 
B)  decarboxylations 
C)  racemizations 
D)  movement of hydroxymethyl groups 
E)  all of these 
A)  transaminations 
B)  decarboxylations 
C)  racemizations 
D)  movement of hydroxymethyl groups 
E)  all of these

Question 7

In the synthesis of pyrimidine nucleotides, the ring system formed just before the attachment of PRPP is

Accepted Answer

A)  5-aminoimidazole 
B)  inosine 
C)  orotate 
D)  xanthine 
A)  5-aminoimidazole 
B)  inosine 
C)  orotate 
D)  xanthine

Question 8

The serine family of amino acids includes synthesis of all the following amino acids, except :

Accepted Answer

A)  Serine. 
B)  Glycine. 
C)  Cysteine. 
D)  Methionine. 
E)  The serine family includes synthesis of all four of these amino acids. 
A)  Serine. 
B)  Glycine. 
C)  Cysteine. 
D)  Methionine. 
E)  The serine family includes synthesis of all four of these amino acids.

Question 9

Which of the following is not an interconversion of nitrogen performed by living organisms?

Accepted Answer

A)  Fixation of atmospheric nitrogen into ammonia. 
B)  Fixation of atmospheric nitrogen into nitrate. 
C)  Nitrification of soil nitrate into ammonia 
D)  Denitrification of nitrogen oxides to gaseous nitrogen. 
E)  All of these are common bioconversions in the nitrogen cycle. 
A)  Fixation of atmospheric nitrogen into ammonia. 
B)  Fixation of atmospheric nitrogen into nitrate. 
C)  Nitrification of soil nitrate into ammonia 
D)  Denitrification of nitrogen oxides to gaseous nitrogen. 
E)  All of these are common bioconversions in the nitrogen cycle.

Question 10

The following two amino acids are key to the transfers of amino groups during breakdown and synthesis of amino acids.

Accepted Answer

A)  GLU and ASP 
B)  GLU and ARG 
C)  GLU and GLN 
D)  ALA and GLN 
E)  ASP and GLN 
A)  GLU and ASP 
B)  GLU and ARG 
C)  GLU and GLN 
D)  ALA and GLN 
E)  ASP and GLN

Question 11

Nitrification is the conversion of

Accepted Answer

A)  nitrogen gas to nitrate. 
B)  nitrogen gas to ammonia. 
C)  nitrate to ammonia. 
D)  nitrate to nitrogen gas. 
E)  ammonia to nitrogen gas. 
A)  nitrogen gas to nitrate. 
B)  nitrogen gas to ammonia. 
C)  nitrate to ammonia. 
D)  nitrate to nitrogen gas. 
E)  ammonia to nitrogen gas.

Question 12

By a simple transamination reaction, intermediates in glycolysis or the Kreb's 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)  Serine. 
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)  Serine. 
E)  All of these amino acids are only one step away from the major metabolic pathways.

Question 13

In the urea cycle, the molecule that is synthesized in the cytosol and transported to the mitochondrial matrix for subsequent reaction is

Accepted Answer

A)  citrulline 
B)  ornithine 
C)  argininosuccinate 
D)  aspartate 
E)  fumarate 
A)  citrulline 
B)  ornithine 
C)  argininosuccinate 
D)  aspartate 
E)  fumarate

Question 14

High protein diets for humans result in the following.

Accepted Answer

A)  Increased nitrogen metabolism. 
B)  A negative nitrogen balance for the body. 
C)  Increased demand for water in the diet. 
D)  Both increased nitrogen metabolism and need for water. 
E)  All of these are consequences of high protein diets. 
A)  Increased nitrogen metabolism. 
B)  A negative nitrogen balance for the body. 
C)  Increased demand for water in the diet. 
D)  Both increased nitrogen metabolism and need for water. 
E)  All of these are consequences of high protein diets.

Question 15

Many antibiotics, especially for viruses and cancer therapy involve inhibition of folic acid reactions, especially because folic acid is essential for this reaction:

Accepted Answer

A)  Synthesis of many amino acids. 
B)  Conversion of uracil to thymine for DNA synthesis. 
C)  Synthesis of deoxyribose for DNA synthesis. 
D)  None of these reactions explains the reason why inhibitors of folic acid act as antibiotics. 
E)  All of these reactions are reasons why inhibitors of folic acid act as antibiotics. 
A)  Synthesis of many amino acids. 
B)  Conversion of uracil to thymine for DNA synthesis. 
C)  Synthesis of deoxyribose for DNA synthesis. 
D)  None of these reactions explains the reason why inhibitors of folic acid act as antibiotics. 
E)  All of these reactions are reasons why inhibitors of folic acid act as antibiotics.

Question 16

Which of the following amino acids does not use glutamic acid as a precursor?

Accepted Answer

A)  arginine 
B)  glutamine 
C)  lysine 
D)  proline 
A)  arginine 
B)  glutamine 
C)  lysine 
D)  proline

Question 17

A characteristic feature of feedback inhibition is that

Accepted Answer

A)  it is wasteful of energy and reducing power in anabolic pathways 
B)  it leads to buildup of the end products of anabolic pathways 
C)  it seldom occurs in the metabolism of compounds of nitrogen 
D)  it commonly appears in biosynthesis of amino acids 
E)  it always involves the inhibition of the first step of a pathway 
A)  it is wasteful of energy and reducing power in anabolic pathways 
B)  it leads to buildup of the end products of anabolic pathways 
C)  it seldom occurs in the metabolism of compounds of nitrogen 
D)  it commonly appears in biosynthesis of amino acids 
E)  it always involves the inhibition of the first step of a pathway

Question 18

Ribonucleotide reductase uses which of the following cofactors?

Accepted Answer

A)  biotin 
B)  thiamine pyrophosphate 
C)  tetrahydrofolate 
D)  thioredoxin 
A)  biotin 
B)  thiamine pyrophosphate 
C)  tetrahydrofolate 
D)  thioredoxin

Question 19

Orotic acid is synthesized from

Accepted Answer

A)  glycine and carbamoyl phosphate. 
B)  arginine and carbamoyl phosphate. 
C)  aspartic acid and carbamoyl phosphate. 
D)  aspartic acid and glutamine. 
A)  glycine and carbamoyl phosphate. 
B)  arginine and carbamoyl phosphate. 
C)  aspartic acid and carbamoyl phosphate. 
D)  aspartic acid and glutamine.

Question 20

The form in which nitrogen waste is removed from the body is dependent mostly on the organism's availability of water.

Accepted Answer

A) True 
 B)False

Exam 23: The Metabolism of Nitrogen

Isoleucine, leucine and valine are all formed from the same amino acid root, aspartic acid.

If an amino acid is ketogenic, then it:

What intermediate of the TCA cycle is produced from aspartic acid during the urea cycle, synthesis of IMP, and conversion from IMP to adenosine?

Which of the following compounds does not serve as an intermediate for the entry of amino acid carbon chains into the major metabolic pathways?

The conversion of glutamate to glutamine is catalyzed by glutamine synthetase and requires ATP.

Pyridoxal phosphate is involved in which of the following reactions?

In the synthesis of pyrimidine nucleotides, the ring system formed just before the attachment of PRPP is

The serine family of amino acids includes synthesis of all the following amino acids, except :

Which of the following is not an interconversion of nitrogen performed by living organisms?

The following two amino acids are key to the transfers of amino groups during breakdown and synthesis of amino acids.

Nitrification is the conversion of

By a simple transamination reaction, intermediates in glycolysis or the Kreb's Cycle can be converted in one step to all of these amino acids, except :

In the urea cycle, the molecule that is synthesized in the cytosol and transported to the mitochondrial matrix for subsequent reaction is

High protein diets for humans result in the following.

Many antibiotics, especially for viruses and cancer therapy involve inhibition of folic acid reactions, especially because folic acid is essential for this reaction:

Which of the following amino acids does not use glutamic acid as a precursor?

A characteristic feature of feedback inhibition is that

Ribonucleotide reductase uses which of the following cofactors?

Orotic acid is synthesized from

The form in which nitrogen waste is removed from the body is dependent mostly on the organism's availability of water.

Biochemistry and the Organization of Cells

Water the Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins Enzymes

The Behavior of Proteins Enzymes Mechanisms and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids How Structure Conveys Information

Biosynthesis of Nucleic Acids Replication

Transcription of the Genetic Code the Biosynthesis of Rna

Protein Synthesis Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses Cancer and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

Integration of Metabolism Cellular Signaling

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