Question 1

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

Accepted Answer

A) True 
 B)False

Question 2

We use the term tetrahydrofolate to designate a family of related compounds. What is the main difference between members of this family?

Accepted Answer

A)  degree of protonation 
B)  number of methyl groups on the heterocylic rings 
C)  number of phosphate groups 
D)  length of the polyglutamate tail group 
A)  degree of protonation 
B)  number of methyl groups on the heterocylic rings 
C)  number of phosphate groups 
D)  length of the polyglutamate tail group

Question 3

An ion commonly found in metalloenzymes and which can undergo reversible oxidation and reduction is

Accepted Answer

A)  Ca++. 
B)  Mg++. 
C)  S-. 
D)  Fe++. 
E)  All of the above 
A)  Ca++. 
B)  Mg++. 
C)  S-. 
D)  Fe++. 
E)  All of the above

Question 4

Mammalian cells can synthesize all needed coenzymes from simple precursors.

Accepted Answer

A) True 
 B)False

Question 5

Vitamin C is a vitamin but not a coenzyme because it

Accepted Answer

A)  does not bind to proteins. 
B)  is a prosthetic group. 
C)  is a reducing agent during hydroxylation of collagen. 
D)  is not required in human diets. 
A)  does not bind to proteins. 
B)  is a prosthetic group. 
C)  is a reducing agent during hydroxylation of collagen. 
D)  is not required in human diets.

Question 6

The ʺ+ʺ sign in NAD+ indicates that

Accepted Answer

A)  this is the reduced form of the coenzyme. 
B)  the nitrogen atom has a positive charge. 
C)  the entire molecule is positively charged. 
D)  it can bind to negatively charged proteins only. 
A)  this is the reduced form of the coenzyme. 
B)  the nitrogen atom has a positive charge. 
C)  the entire molecule is positively charged. 
D)  it can bind to negatively charged proteins only.

Question 7

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 8

Ubiquinone and plastoquinone transport electrons in membranes.

Accepted Answer

A) True 
 B)False

Question 9

Rickets in children and osteomalacia in adults is caused by a lack of .

Accepted Answer

A)  thiamin 
B)  hemoglobin 
C)  vitamin D 
D)  vitamin B12 
A)  thiamin 
B)  hemoglobin 
C)  vitamin D 
D)  vitamin B12

Question 10

Which coenzyme is likely involved in the reaction shown below?

Accepted Answer

A)  TPP 
B)  biotin 
C)  coenzyme A 
D)  FMN 
A)  TPP 
B)  biotin 
C)  coenzyme A 
D)  FMN

Question 11

Vitamin C is a coenzyme during the hydroxylation of collagen.

Accepted Answer

A) True 
 B)False

Question 12

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 13

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

Question 14

Two-electron transfer reactions can be linked to one-electron transfer reactions by

Accepted Answer

A)  formation of semiquinones. 
B)  a [Fe-S] cluster. 
C)  NADH and NADPH. 
D)  B and C 
E)  A and C 
A)  formation of semiquinones. 
B)  a [Fe-S] cluster. 
C)  NADH and NADPH. 
D)  B and C 
E)  A and C

Question 15

The oxidized forms of cytochromes c absorbs more strongly than the reduced form at the Soret band near 400 nm.

Accepted Answer

A) True 
 B)False

Question 16

Which does not return to its original form after each catalysis?

Accepted Answer

A)  prosthetic groups 
B)  cosubstrates 
C)  metalloenzyme 
D)  None of the above. They all return to their original forms. 
A)  prosthetic groups 
B)  cosubstrates 
C)  metalloenzyme 
D)  None of the above. They all return to their original forms.

Question 17

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 18

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 19

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 20

All enzymes require metallic cations to achieve full catalytic activity.

Accepted Answer

A) True 
 B)False

Exam 7: Coenzymes and Vitamins

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

We use the term tetrahydrofolate to designate a family of related compounds. What is the main difference between members of this family?

An ion commonly found in metalloenzymes and which can undergo reversible oxidation and reduction is

Mammalian cells can synthesize all needed coenzymes from simple precursors.

Vitamin C is a vitamin but not a coenzyme because it

The ʺ+ʺ sign in NAD+ indicates that

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

Ubiquinone and plastoquinone transport electrons in membranes.

Rickets in children and osteomalacia in adults is caused by a lack of .

Which coenzyme is likely involved in the reaction shown below?

Vitamin C is a coenzyme during the hydroxylation of collagen.

Vitamin D helps control the utilization of which ion?

Which characterizes cobalamin?

Two-electron transfer reactions can be linked to one-electron transfer reactions by

The oxidized forms of cytochromes c absorbs more strongly than the reduced form at the Soret band near 400 nm.

Which does not return to its original form after each catalysis?

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

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

Which structure in shown?

All enzymes require metallic cations to achieve full catalytic activity.

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 Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

Filters

The ʺ+ʺ sign in NAD⁺indicates that