Question 1

Which characterizes cobalamin?

Accepted Answer

A) Participates in the conversion of homocysteine to methionine. 
B) Contains a corrin ring prosthetic group. 
C) Requires a glycoprotein for its absorption. 
D) All of the above. 
A) Participates in the conversion of homocysteine to methionine. 
B) Contains a corrin ring prosthetic group. 
C) Requires a glycoprotein for its absorption. 
D) All of the above. D

Question 2

The role of zinc in the mechanisms of carbonic anhydrase is to

Accepted Answer

A) maintain the configuration of the holoenzyme. 
B) bind to three histidine residues. 
C) produce a nucleophilic attack on the substrate. 
D) promote ionization of bound water. 
E) produce an electrophilic attack on the substrate. 
A) maintain the configuration of the holoenzyme. 
B) bind to three histidine residues. 
C) produce a nucleophilic attack on the substrate. 
D) promote ionization of bound water. 
E) produce an electrophilic attack on the substrate. D

Question 3

Tetrahydrofolate is a more oxidized form of the vitamin folate from which it is derived.

Accepted Answer

A) True 
 B)False  False

Question 4

When NAD+ is reduced,the UV absorbance at 340 nm

Accepted Answer

A) decreases. 
B) increases. 
C) stays the same. 
D) decreases,then increases. 
E) increases,then decreases. 
A) decreases. 
B) increases. 
C) stays the same. 
D) decreases,then increases. 
E) increases,then decreases.

Question 5

Which structure in shown?

Accepted Answer

A) Retinol. 
B) Retinal. 
C) Retinoic acid. 
D) β-carotene. 
A) Retinol. 
B) Retinal. 
C) Retinoic acid. 
D) β-carotene.

Question 6

Enzymes that have FAD or FMN as prosthetic groups are called

Accepted Answer

A) flavoenzymes. 
B) flavoproteins. 
C) Old Yellow Enzyme. 
D) All of the above. 
E) A and B only. 
A) flavoenzymes. 
B) flavoproteins. 
C) Old Yellow Enzyme. 
D) All of the above. 
E) A and B only.

Question 7

Minerals which are cofactors may be reversibly bound and are then usually directly involved in catalytic reactions.

Accepted Answer

A) True 
 B)False

Question 8

What is the role of the magnesium ion in kinases that require the magnesium-ATP complex to donate phosphoryl groups?

Accepted Answer

A) Maintain the configuration of the holoenzyme. 
B) Shield the charged phosphate groups of ATP. 
C) Produce an electrophilic attack on the substrate. 
D) Promote ionization of bound water. 
E) Produce ionization of the substrate to be phosphorylated. 
A) Maintain the configuration of the holoenzyme. 
B) Shield the charged phosphate groups of ATP. 
C) Produce an electrophilic attack on the substrate. 
D) Promote ionization of bound water. 
E) Produce ionization of the substrate to be phosphorylated.

Question 9

Which coenzyme is composed of a 2-mercaptoethylamine unit,the vitamin pantothenate and an ADP moiety?

Accepted Answer

A) NADPH. 
B) Biotin. 
C) Coenzyme A. 
D) Ubiquinone. 
A) NADPH. 
B) Biotin. 
C) Coenzyme A. 
D) Ubiquinone.

Question 10

Vitamin D helps control the utilization of which ion?

Accepted Answer

A) Mg²+ 
B) Ca²+ 
C) Fe²+ 
D) CO²+ 
A) Mg²+ 
B) Ca²+ 
C) Fe²+ 
D) CO²+

Question 11

The degradation of aspartic acid to oxaloacetic acid is catalyzed by an enzyme with ________ as its prosthetic group.

Accepted Answer

A) thiamine 
B) biotin 
C) pyridoxal phosphate 
D) vitamin B₁₂ 
A) thiamine 
B) biotin 
C) pyridoxal phosphate 
D) vitamin B₁₂

Question 12

Cobalamin is synthesized by most organisms from simple precursors and does not need to be in the diet.

Accepted Answer

A) True 
 B)False

Question 13

Organic compounds are coenzymes and cofactors while inorganic ions are cofactors only.

Accepted Answer

A) True 
 B)False

Question 14

A nucleotide-sugar coenzyme involved in carbohydrate metabolism (UDP-glucose)is formed when UTP reacts with a glucose molecule.More UTP is made available for additional reactions by the transfer of a phosphate group from

Accepted Answer

A) another carbohydrate. 
B) ATP. 
C) ADP. 
D) UTP. 
E) UDP. 
A) another carbohydrate. 
B) ATP. 
C) ADP. 
D) UTP. 
E) UDP.

Question 15

Vitamin deficiency diseases are a result of the lack of formation of certain coenzymes.

Accepted Answer

A) True 
 B)False

Question 16

Lack of thiamine (vitamin B1)leads to the disease beriberi.

Accepted Answer

A) True 
 B)False

Question 17

Cytochromes are classified a,b or c based on

Accepted Answer

A) solubility. 
B) The Soret band in absorption spectra. 
C) The beta band in absorption spectra. 
D) The alpha band in absorption spectra. 
A) solubility. 
B) The Soret band in absorption spectra. 
C) The beta band in absorption spectra. 
D) The alpha band in absorption spectra.

Question 18

Metal-activated enzymes may require a metal ion or simply be stimulated in the presence of the ion.

Accepted Answer

A) True 
 B)False

Question 19

Raw egg white contains a protein called avidin.What happens if you ingest raw egg whites?

Accepted Answer

A) Avidin helps to build muscle tissue. 
B) Avidin is the main protein involved in Salmonella poisoning. 
C) Avidin binds onto the coenzyme biotin and interferes with its absorption. 
D) Avidin,also called intrinsic factor,helps transport cobalamin into the cells of the small intestine. 
A) Avidin helps to build muscle tissue. 
B) Avidin is the main protein involved in Salmonella poisoning. 
C) Avidin binds onto the coenzyme biotin and interferes with its absorption. 
D) Avidin,also called intrinsic factor,helps transport cobalamin into the cells of the small intestine.

Question 20

Which vitamin is shown below?

Accepted Answer

A) Vitamin C. 
B) Thiamin (vitamin B1). 
C) cobalamin (vitamin B12). 
D) folate. 
A) Vitamin C. 
B) Thiamin (vitamin B1). 
C) cobalamin (vitamin B12). 
D) folate.

Exam 7: Coenzymes and Vitamins

Which characterizes cobalamin?

The role of zinc in the mechanisms of carbonic anhydrase is to

Tetrahydrofolate is a more oxidized form of the vitamin folate from which it is derived.

When NAD+ is reduced,the UV absorbance at 340 nm

Which structure in shown?

Enzymes that have FAD or FMN as prosthetic groups are called

Minerals which are cofactors may be reversibly bound and are then usually directly involved in catalytic reactions.

What is the role of the magnesium ion in kinases that require the magnesium-ATP complex to donate phosphoryl groups?

Which coenzyme is composed of a 2-mercaptoethylamine unit,the vitamin pantothenate and an ADP moiety?

Vitamin D helps control the utilization of which ion?

The degradation of aspartic acid to oxaloacetic acid is catalyzed by an enzyme with ________ as its prosthetic group.

Cobalamin is synthesized by most organisms from simple precursors and does not need to be in the diet.

Organic compounds are coenzymes and cofactors while inorganic ions are cofactors only.

A nucleotide-sugar coenzyme involved in carbohydrate metabolism (UDP-glucose)is formed when UTP reacts with a glucose molecule.More UTP is made available for additional reactions by the transfer of a phosphate group from

Vitamin deficiency diseases are a result of the lack of formation of certain coenzymes.

Lack of thiamine (vitamin B1)leads to the disease beriberi.

Cytochromes are classified a,b or c based on

Metal-activated enzymes may require a metal ion or simply be stimulated in the presence of the ion.

Raw egg white contains a protein called avidin.What happens if you ingest raw egg whites?

Which vitamin is shown below?

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

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

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

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