Question 1

How is cancer chemotherapy related to purine biosyntheis?

Accepted Answer

A)  rapidly dividing cells require more purine biosynthesis and some chemotherapy drugs inhibit a key enzyme in purine biosynthesis 
B)  aminopterin is a good chemotherapy drug because it inhibits aspartate transcarbamoylase 
C)  cancer cells lack folic acid, and chemotherapy drugs like sulfanamide act by overproducing folic acid, which is then poisonous to the cancer cells 
D)  none of these 
A)  rapidly dividing cells require more purine biosynthesis and some chemotherapy drugs inhibit a key enzyme in purine biosynthesis 
B)  aminopterin is a good chemotherapy drug because it inhibits aspartate transcarbamoylase 
C)  cancer cells lack folic acid, and chemotherapy drugs like sulfanamide act by overproducing folic acid, which is then poisonous to the cancer cells 
D)  none of these

Question 2

Folic acid is an important factor necessary for the production of three of the four deoxyribonucleotides needed for DNA synthesis.For which dNTP is this factor not necessary?

Accepted Answer

A)  dATP 
B)  dCTP 
C)  dGTP 
D)  dTTP 
A)  dATP 
B)  dCTP 
C)  dGTP 
D)  dTTP

Question 3

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 4

The conversion of uracil to thymine requires

Accepted Answer

A)  a one-carbon transfer with S-adenosylmethionine as the donor 
B)  a one-carbon transfer with tetrahydrofolate as the donor 
C)  a one-carbon transfer with biotin as the donor 
D)  a one-carbon transfer with oxaloacetate as the donor 
A)  a one-carbon transfer with S-adenosylmethionine as the donor 
B)  a one-carbon transfer with tetrahydrofolate as the donor 
C)  a one-carbon transfer with biotin as the donor 
D)  a one-carbon transfer with oxaloacetate as the donor

Question 5

Nitrogen fixation in legumes may use as much as half of the ATP made in the plant.

Accepted Answer

A) True 
 B)False

Question 6

The initial,common intermediate in purine catabolism for both AMP and GMP is

Accepted Answer

A)  xanthine 
B)  hypoxanthine 
C)  inosine 
D)  uric acid 
A)  xanthine 
B)  hypoxanthine 
C)  inosine 
D)  uric acid

Question 7

The carbon skeletons of many amino acids can be used to replenish the intermediates of the citric acid cycle.

Accepted Answer

A) True 
 B)False

Question 8

Which reaction converts orotate monophosphate into uracil monophosphate?

Accepted Answer

A)  a transamination 
B)  a methylation 
C)  a decarboxylation 
D)  a carboxylation 
A)  a transamination 
B)  a methylation 
C)  a decarboxylation 
D)  a carboxylation

Question 9

Which group of small molecules best fit the boxes associated with the reaction shown?

Accepted Answer

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

Question 10

High protein foods are not advisable for the long distance runner during a race because they increase the need for water and for urination.

Accepted Answer

A) True 
 B)False

Question 11

Glutamine synthetase is subject to feedback inhibition by which of the following chemicals?

Accepted Answer

A)  histidine 
B)  carbamoyl phosphate 
C)  cytidine triphosphate (CTP) 
D)  All of these 
A)  histidine 
B)  carbamoyl phosphate 
C)  cytidine triphosphate (CTP) 
D)  All of these

Question 12

Deoxyribonucleotides are formed

Accepted Answer

A)  by a pathway entirely different from that of ribonucleotides 
B)  exclusively by hydrolysis of the DNA of the organism 
C)  as monophosphates by reduction of ribonucleoside monophosphates 
D)  as diphosphates by reduction of ribonucleoside disphosphates 
A)  by a pathway entirely different from that of ribonucleotides 
B)  exclusively by hydrolysis of the DNA of the organism 
C)  as monophosphates by reduction of ribonucleoside monophosphates 
D)  as diphosphates by reduction of ribonucleoside disphosphates

Question 13

The carbon skeleton used to make serine is:

Accepted Answer

A)  3-phosphoglycerate 
B)  glutamate 
C)  á-ketoglutarate 
D)  oxaloacetate 
E)  pyruvate 
A)  3-phosphoglycerate 
B)  glutamate 
C)  á-ketoglutarate 
D)  oxaloacetate 
E)  pyruvate

Question 14

The synthesis of amino acids occurs in about 5 or 6 related families of amino acids.

Accepted Answer

A) True 
 B)False

Question 15

Denitrification is carried out by

Accepted Answer

A)  animals. 
B)  green plants. 
C)  soil bacteria. 
D)  all of the above. 
A)  animals. 
B)  green plants. 
C)  soil bacteria. 
D)  all of the above.

Question 16

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 
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

Question 17

A metabolic intermediate that is not a precursor for an amino acid family is

Accepted Answer

A)  a-ketoglutarate 
B)  pyruvate 
C)  glyceraldehyde-3-phosphate 
D)  oxaloacetate 
A)  a-ketoglutarate 
B)  pyruvate 
C)  glyceraldehyde-3-phosphate 
D)  oxaloacetate

Question 18

There is a curious diversity of nature for the two sulfur containing amino acids.Methionine is made from cysteine in bacteria,but cysteine is made from methionine in mammals.

Accepted Answer

A) True 
 B)False

Question 19

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 20

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.

Exam 23: The Metabolism of Nitrogen

How is cancer chemotherapy related to purine biosyntheis?

Folic acid is an important factor necessary for the production of three of the four deoxyribonucleotides needed for DNA synthesis.For which dNTP is this factor not necessary?

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

The conversion of uracil to thymine requires

Nitrogen fixation in legumes may use as much as half of the ATP made in the plant.

The initial,common intermediate in purine catabolism for both AMP and GMP is

The carbon skeletons of many amino acids can be used to replenish the intermediates of the citric acid cycle.

Which reaction converts orotate monophosphate into uracil monophosphate?

Which group of small molecules best fit the boxes associated with the reaction shown?

High protein foods are not advisable for the long distance runner during a race because they increase the need for water and for urination.

Glutamine synthetase is subject to feedback inhibition by which of the following chemicals?

Deoxyribonucleotides are formed

The carbon skeleton used to make serine is:

The synthesis of amino acids occurs in about 5 or 6 related families of amino acids.

Denitrification is carried out by

A characteristic feature of feedback inhibition is that

A metabolic intermediate that is not a precursor for an amino acid family is

There is a curious diversity of nature for the two sulfur containing amino acids.Methionine is made from cysteine in bacteria,but cysteine is made from methionine in mammals.

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

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

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: 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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