Question 1

One of the enzymes involved in glycolysis is phosphofructokinase.What type of biochemical reaction is it catalyzing?

Accepted Answer

A) Transfer of a carbonyl group from glucose to fructose. 
B) Removal of a phosphate group from fructose-6-phosphate. 
C) Transfer of a phosphate group from ATP to fructose-6-phosphate. 
D) Transfer of a phosphate group from fructose-1,6-bisphosphate to fructose. 
E) none of the above 
A) Transfer of a carbonyl group from glucose to fructose. 
B) Removal of a phosphate group from fructose-6-phosphate. 
C) Transfer of a phosphate group from ATP to fructose-6-phosphate. 
D) Transfer of a phosphate group from fructose-1,6-bisphosphate to fructose. 
E) none of the above

Question 2

Another term for substances that bind irreversibly with the active site of an enzyme is

Accepted Answer

A) activators. 
B) poisons. 
C) coenzymes. 
D) hormones. 
E) zymogens. 
A) activators. 
B) poisons. 
C) coenzymes. 
D) hormones. 
E) zymogens.

Question 3

Enzymes that are affected by the binding of an activator are called

Accepted Answer

A) zymogens. 
B) proenzymes. 
C) allosteric enzymes. 
D) induced enzymes. 
A) zymogens. 
B) proenzymes. 
C) allosteric enzymes. 
D) induced enzymes.

Question 4

Which aspect of enzyme structure is related to our dietary need for trace minerals?

Accepted Answer

A) cofactor 
B) active site 
C) turnover number 
D) chirality 
E) none of these 
A) cofactor 
B) active site 
C) turnover number 
D) chirality 
E) none of these

Question 5

Match the following.
-hydrolase

Accepted Answer

A) a type of enzyme that catalyzes the breakdown of large molecules by reaction with water 
B) a type of enzyme that catalyzes the transfer of a functional group from one molecule to another 
C) a substance that prevents harmful reactions of free radicals 
D) an inactive form of an enzyme;also called a proenzyme 
E) any process which decreases the rate of an enzyme catalyzed reaction
F)a type of enzyme that catalyzes the joining of two molecules together
G)a description of the catalytic activity of an enzyme,where a small value means that very few molecules are acted on in a unit of time
H)a description of enzyme activity based on the ability of the enzyme to change shape in order to accommodate substrate molecules
I)any process that increases the rate of an enzyme catalyzed reaction
J)a type of enzyme that catalyzes the removal of a small molecule from a larger one
K)a description of enzyme activity based on an exact match between the shapes of the active site and the substrate molecule
L)a small organic molecule necessary for good health that must be obtained in the diet
M)a type of enzyme that catalyzes the internal rearrangement of molecules
N)a type of enzyme that catalyzes oxidation or reduction reactions 
A) a type of enzyme that catalyzes the breakdown of large molecules by reaction with water 
B) a type of enzyme that catalyzes the transfer of a functional group from one molecule to another 
C) a substance that prevents harmful reactions of free radicals 
D) an inactive form of an enzyme;also called a proenzyme 
E) any process which decreases the rate of an enzyme catalyzed reaction
F)a type of enzyme that catalyzes the joining of two molecules together
G)a description of the catalytic activity of an enzyme,where a small value means that very few molecules are acted on in a unit of time
H)a description of enzyme activity based on the ability of the enzyme to change shape in order to accommodate substrate molecules
I)any process that increases the rate of an enzyme catalyzed reaction
J)a type of enzyme that catalyzes the removal of a small molecule from a larger one
K)a description of enzyme activity based on an exact match between the shapes of the active site and the substrate molecule
L)a small organic molecule necessary for good health that must be obtained in the diet
M)a type of enzyme that catalyzes the internal rearrangement of molecules
N)a type of enzyme that catalyzes oxidation or reduction reactions

Question 6

A deficiency in in which of the following has been shown to cause goiter?

Accepted Answer

A) magnesium 
B) iodine 
C) selenium 
D) chlorine 
E) chromium 
A) magnesium 
B) iodine 
C) selenium 
D) chlorine 
E) chromium

Question 7

A form of inhibition that occurs by covalent modification is the

Accepted Answer

A) phosphorylation of an active site by ATP. 
B) dephosphorylation of an active site by hydrolysis. 
C) transfer of a phosphate group to ADP. 
D) all of these 
A) phosphorylation of an active site by ATP. 
B) dephosphorylation of an active site by hydrolysis. 
C) transfer of a phosphate group to ADP. 
D) all of these

Question 8

Substances the bind to an enzyme and increase its activity are called

Accepted Answer

A) negative regulators. 
B) positive regulators. 
C) allosteric regulators. 
D) neutral regulators. 
A) negative regulators. 
B) positive regulators. 
C) allosteric regulators. 
D) neutral regulators.

Question 9

A model that explains how the substrate fits exactly into the active site of an enzyme is called

Accepted Answer

A) a coenzyme. 
B) an induced-fit. 
C) a lock-and-key. 
D) substrate specific. 
E) an active site. 
A) a coenzyme. 
B) an induced-fit. 
C) a lock-and-key. 
D) substrate specific. 
E) an active site.

Question 10

Enzymes that are affected by the binding of an inhibitor are called

Accepted Answer

A) induced enzymes. 
B) allosteric enzymes. 
C) proenzymes. 
D) zymogens. 
E) controlled enzymes. 
A) induced enzymes. 
B) allosteric enzymes. 
C) proenzymes. 
D) zymogens. 
E) controlled enzymes.

Question 11

An enzyme that catalyzes addition or removal of hydrogen or oxygen on substrate molecules is a(an)

Accepted Answer

A) ligase. 
B) isomerase. 
C) oxidoreductase. 
D) transferase. 
E) hydrolase. 
A) ligase. 
B) isomerase. 
C) oxidoreductase. 
D) transferase. 
E) hydrolase.

Question 12

Some enzymes are produced as zymogens because

Accepted Answer

A) the reactions they catalyze are undesirable at the site of production. 
B) they must have both an active site and an allosteric site,and these can't be produced simultaneously. 
C) the actual enzyme molecules are so large that they must be produced in pieces and assembled as needed. 
D) the pH at the site of production is very different from the pH at the site where they are used. 
E) none of these 
A) the reactions they catalyze are undesirable at the site of production. 
B) they must have both an active site and an allosteric site,and these can't be produced simultaneously. 
C) the actual enzyme molecules are so large that they must be produced in pieces and assembled as needed. 
D) the pH at the site of production is very different from the pH at the site where they are used. 
E) none of these

Question 13

In order to have full activity,some enzymes require certain metal ions,such as Mg2+ or Zn2+.This component is called a

Accepted Answer

A) cofactor. 
B) coenzyme. 
C) regulator. 
D) substrate. 
E) inhibitor. 
A) cofactor. 
B) coenzyme. 
C) regulator. 
D) substrate. 
E) inhibitor.

Question 14

Which of the following vitamins has antioxidant properties?

Accepted Answer

A) vitamin C 
B) vitamin E 
C) vitamin K 
D) vitamin B 
E) vitamins C and E 
A) vitamin C 
B) vitamin E 
C) vitamin K 
D) vitamin B 
E) vitamins C and E

Question 15

The theory of enzyme mechanism that suggests a flexible molecule whose shape is altered by the reaction conditions is the ________ model.

Accepted Answer

A) coenzyme 
B) induced-fit 
C) lock-and-key 
D) substrate specific 
E) active site 
A) coenzyme 
B) induced-fit 
C) lock-and-key 
D) substrate specific 
E) active site

Question 16

Enzymes have an optimum temperature for their catalytic activity.This is best explained by the balance between the ________ number of collisions and the ________ rate of denaturation of the enzyme as temperatures increase.

Accepted Answer

A) increased;increased 
B) decreased;increased 
C) increased;decreased 
D) decreased;decreased 
E) none of the above 
A) increased;increased 
B) decreased;increased 
C) increased;decreased 
D) decreased;decreased 
E) none of the above

Question 17

An enzyme functions best at its optimal temperature.What would possibly happen if the temperature is increased greatly?

Accepted Answer

A) The enzyme would become denatured. 
B) The reaction rate would increase. 
C) The reaction would slow down. 
D) There would be no effect on the enzyme's activity. 
A) The enzyme would become denatured. 
B) The reaction rate would increase. 
C) The reaction would slow down. 
D) There would be no effect on the enzyme's activity.

Question 18

Match the following.
-induced-fit model

Accepted Answer

A) a type of enzyme that catalyzes the breakdown of large molecules by reaction with water 
B) a type of enzyme that catalyzes the transfer of a functional group from one molecule to another 
C) a substance that prevents harmful reactions of free radicals 
D) an inactive form of an enzyme;also called a proenzyme 
E) any process which decreases the rate of an enzyme catalyzed reaction
F)a type of enzyme that catalyzes the joining of two molecules together
G)a description of the catalytic activity of an enzyme,where a small value means that very few molecules are acted on in a unit of time
H)a description of enzyme activity based on the ability of the enzyme to change shape in order to accommodate substrate molecules
I)any process that increases the rate of an enzyme catalyzed reaction
J)a type of enzyme that catalyzes the removal of a small molecule from a larger one
K)a description of enzyme activity based on an exact match between the shapes of the active site and the substrate molecule
L)a small organic molecule necessary for good health that must be obtained in the diet
M)a type of enzyme that catalyzes the internal rearrangement of molecules
N)a type of enzyme that catalyzes oxidation or reduction reactions 
A) a type of enzyme that catalyzes the breakdown of large molecules by reaction with water 
B) a type of enzyme that catalyzes the transfer of a functional group from one molecule to another 
C) a substance that prevents harmful reactions of free radicals 
D) an inactive form of an enzyme;also called a proenzyme 
E) any process which decreases the rate of an enzyme catalyzed reaction
F)a type of enzyme that catalyzes the joining of two molecules together
G)a description of the catalytic activity of an enzyme,where a small value means that very few molecules are acted on in a unit of time
H)a description of enzyme activity based on the ability of the enzyme to change shape in order to accommodate substrate molecules
I)any process that increases the rate of an enzyme catalyzed reaction
J)a type of enzyme that catalyzes the removal of a small molecule from a larger one
K)a description of enzyme activity based on an exact match between the shapes of the active site and the substrate molecule
L)a small organic molecule necessary for good health that must be obtained in the diet
M)a type of enzyme that catalyzes the internal rearrangement of molecules
N)a type of enzyme that catalyzes oxidation or reduction reactions

Question 19

Noncompetitive inhibition can be overcome by

Accepted Answer

A) increasing the concentration of substrate. 
B) increasing the concentration of enzyme. 
C) decreasing the concentration of inhibitor. 
D) decreasing the concentration of products. 
E) decreasing the concentration of substrate. 
A) increasing the concentration of substrate. 
B) increasing the concentration of enzyme. 
C) decreasing the concentration of inhibitor. 
D) decreasing the concentration of products. 
E) decreasing the concentration of substrate.

Question 20

When a molecule other than the correct substrate interacts with some part of an enzyme to alter the shape of the active site,the process is called

Accepted Answer

A) competitive inhibition. 
B) noncompetitive inhibition. 
C) irreversible inhibition. 
D) activation. 
E) covalent modification. 
A) competitive inhibition. 
B) noncompetitive inhibition. 
C) irreversible inhibition. 
D) activation. 
E) covalent modification.

Exam 19: Enzymes and Vitamins

One of the enzymes involved in glycolysis is phosphofructokinase.What type of biochemical reaction is it catalyzing?

Another term for substances that bind irreversibly with the active site of an enzyme is

Enzymes that are affected by the binding of an activator are called

Which aspect of enzyme structure is related to our dietary need for trace minerals?

Match the following. -hydrolase

A deficiency in in which of the following has been shown to cause goiter?

A form of inhibition that occurs by covalent modification is the

Substances the bind to an enzyme and increase its activity are called

A model that explains how the substrate fits exactly into the active site of an enzyme is called

Enzymes that are affected by the binding of an inhibitor are called

An enzyme that catalyzes addition or removal of hydrogen or oxygen on substrate molecules is a(an)

Some enzymes are produced as zymogens because

In order to have full activity,some enzymes require certain metal ions,such as Mg2+ or Zn2+.This component is called a

Which of the following vitamins has antioxidant properties?

The theory of enzyme mechanism that suggests a flexible molecule whose shape is altered by the reaction conditions is the ________ model.

Enzymes have an optimum temperature for their catalytic activity.This is best explained by the balance between the ________ number of collisions and the ________ rate of denaturation of the enzyme as temperatures increase.

An enzyme functions best at its optimal temperature.What would possibly happen if the temperature is increased greatly?

Match the following. -induced-fit model

Noncompetitive inhibition can be overcome by

When a molecule other than the correct substrate interacts with some part of an enzyme to alter the shape of the active site,the process is called

Matter and Measurements

Atoms and the Periodic Table

Ionic Compounds

Molecular Compounds

Classification and Balancing of Chemical Reactions

Chemical Reactions: Mole and Mass Relationships

Chemical Reactions: Energy, rates, and Equilibrium

Gases, liquids, and Solids

Solutions

Acids and Bases

Nuclear Chemistry

Introduction to Organic Chemistry: Alkanes

Alkenes, alkynes, and Aromatic Compounds

Some Compounds With Oxygen, sulfur, or a Halogen

Aldehydes and Ketones

Amines

Carboxylic Acids and Their Derivatives

Amino Acids and Proteins

Carbohydrates

The Generation of Biochemical Energy

Carbohydrate Metabolism

Lipids

Lipid Metabolism

Protein and Amino Acid Metabolism

Nucleic Acids and Protein Synthesis

Genomics

Chemical Messengers: Hormones, neurotransmitters, and Drugs

Body Fluids

Filters

In order to have full activity,some enzymes require certain metal ions,such as Mg²⁺ or Zn²⁺.This component is called a

Enzymes have an optimum temperature for their catalytic activity.This is best explained by the balance between the number of collisions and the rate of denaturation of the enzyme as temperatures increase.