Question 1

____ is an example of a cofactor required by an enzyme.

Accepted Answer

A) Acetyl coenzyme A 
B) The ferrous (Fe2+)ion 
C) Lipoamide 
D) The sodium ion 
A) Acetyl coenzyme A 
B) The ferrous (Fe2+)ion 
C) Lipoamide 
D) The sodium ion B

Question 2

Which statement does not apply to the lock and key theory?

Accepted Answer

A) It explains the functioning of enzymes. 
B) It explains the need for a specific three dimensional structure found in proteins. 
C) It explains the reason why a particular enzyme is involved with one substrate. 
D) It explains why a substrate-enzyme complex is so difficult to separate. 
A) It explains the functioning of enzymes. 
B) It explains the need for a specific three dimensional structure found in proteins. 
C) It explains the reason why a particular enzyme is involved with one substrate. 
D) It explains why a substrate-enzyme complex is so difficult to separate. D

Question 3

21,000 molecules were acted on by a single molecule of an enzyme in 15 minutes. What is the turnover number?

Accepted Answer

A) 23 
B) 84 000 
C) 1400 
D) 480 
A) 23 
B) 84 000 
C) 1400 
D) 480 C

Question 4

Many drugs act as competitive inhibitors.

Accepted Answer

A) True 
 B)False

Question 5

Enzyme concentration has what effect on the rate of an enzyme catalyzed reaction?

Accepted Answer

A) increases 
B) decreases 
C) no effect 
D) increases until reaching a maximum 
A) increases 
B) decreases 
C) no effect 
D) increases until reaching a maximum

Question 6

An enzyme name of maltase indicates that the substrate is a carbohydrate.

Accepted Answer

A) True 
 B)False

Question 7

All enzymes catalyze specific reactions which makes it simpler to understand the chemistry of the living cell.

Accepted Answer

A) True 
 B)False

Question 8

The use of antibiotic creams and ointments should be restricted. Why?

Accepted Answer

A) The excessive use will affect the flexibility of the skin in the immediate area. 
B) There is a possibility that the antibiotic will cause the skin to become dry. 
C) There is a possibility that antibiotic immune strains of bacteria will develop. 
D) There is more than one correct response. 
A) The excessive use will affect the flexibility of the skin in the immediate area. 
B) There is a possibility that the antibiotic will cause the skin to become dry. 
C) There is a possibility that antibiotic immune strains of bacteria will develop. 
D) There is more than one correct response.

Question 9

The optimum temperature for most enzymes is in the range of ____.

Accepted Answer

A) 25-40 ° C 
B) 0-25 ° C 
C) 50-70 ° C 
D) 40-60 ° C 
A) 25-40 ° C 
B) 0-25 ° C 
C) 50-70 ° C 
D) 40-60 ° C

Question 10

An enzyme is operating at its optimum pH. If the pH were increased, how would the rate of the enzyme-catalyzed reaction change?

Accepted Answer

A) increase 
B) decrease 
C) could increase or decrease 
D) would not change 
A) increase 
B) decrease 
C) could increase or decrease 
D) would not change

Question 11

Consider the following reaction.  
The enzyme that would be placed over the arrow is a _____ .

Accepted Answer

A) ligase 
B) lyase 
C) hydrolase 
D) transferase 
A) ligase 
B) lyase 
C) hydrolase 
D) transferase

Question 12

The turnover number represents the enzyme concentration.

Accepted Answer

A) True 
 B)False

Question 13

What is the function of an inhibitor?

Accepted Answer

A) slow down the rate of reaction 
B) inhibit the effect of temperature and pH changes on enzyme activity 
C) inhibit substrate effects on other chemicals in the reaction environment 
D) slow down the interaction between the solvent and the substrate 
A) slow down the rate of reaction 
B) inhibit the effect of temperature and pH changes on enzyme activity 
C) inhibit substrate effects on other chemicals in the reaction environment 
D) slow down the interaction between the solvent and the substrate

Question 14

​ _____ _____ is the characteristic of an enzyme that acts on only one substance.

Accepted Answer

Absolute s

Question 15

Noncompetitive inhibitors often resemble the natural substrate in structure.

Accepted Answer

A) True 
 B)False

Question 16

The conversion of a zymogen into an enzyme usually involves another enzyme.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following is true of a noncompetitive inhibitor?

Accepted Answer

A) resembles the substrate 
B) binds at a site other than the active site 
C) can be reversed by adding more substrate 
D) more than one response is correct 
A) resembles the substrate 
B) binds at a site other than the active site 
C) can be reversed by adding more substrate 
D) more than one response is correct

Question 18

Pepsin is named because it catalyzes a hydrolysis reaction, and the IEC uses "in" as the word ending to indicate hydrolysis reaction.

Accepted Answer

A) True 
 B)False

Question 19

The region of an enzyme where the substrate molecule fits is called the

Accepted Answer

A) active site. 
B) substrate site. 
C) substrate bond. 
D) primary site. 
A) active site. 
B) substrate site. 
C) substrate bond. 
D) primary site.

Question 20

Enzyme assays are reported in international units (IU). By the definition of an IU, the quantity of enzyme present is measured, not the chemical activity.

Accepted Answer

A) True 
 B)False

Exam 20: Enzymes

____ is an example of a cofactor required by an enzyme.

Which statement does not apply to the lock and key theory?

21,000 molecules were acted on by a single molecule of an enzyme in 15 minutes. What is the turnover number?

Many drugs act as competitive inhibitors.

Enzyme concentration has what effect on the rate of an enzyme catalyzed reaction?

An enzyme name of maltase indicates that the substrate is a carbohydrate.

All enzymes catalyze specific reactions which makes it simpler to understand the chemistry of the living cell.

The use of antibiotic creams and ointments should be restricted. Why?

The optimum temperature for most enzymes is in the range of ____.

An enzyme is operating at its optimum pH. If the pH were increased, how would the rate of the enzyme-catalyzed reaction change?

Consider the following reaction. The enzyme that would be placed over the arrow is a _____ .

The turnover number represents the enzyme concentration.

What is the function of an inhibitor?

​ _____ _____ is the characteristic of an enzyme that acts on only one substance.

Noncompetitive inhibitors often resemble the natural substrate in structure.

The conversion of a zymogen into an enzyme usually involves another enzyme.

Which of the following is true of a noncompetitive inhibitor?

Pepsin is named because it catalyzes a hydrolysis reaction, and the IEC uses "in" as the word ending to indicate hydrolysis reaction.

The region of an enzyme where the substrate molecule fits is called the

Enzyme assays are reported in international units (IU). By the definition of an IU, the quantity of enzyme present is measured, not the chemical activity.

Matter, Measurements, and Calculations

Atoms and Molecules

Electronic Structure and the Periodic Law

Forces Between Particles

Chemical Reactions

The States of Matter

Solutions and Colloids

Reaction Rates and Equilibrium

Acids, Bases, and Salts

Radioactivity and Nuclear Processes

Organic Compounds: Alkanes

Unsaturated Hydrocarbons

Alcohols, Phenols, and Ethers

Aldehydes and Ketones

Carboxylic Acids and Esters

Amines and Amides

Carbohydrates

Lipids

Proteins

Nucleic Acids and Protein Synthesis

Nutrition and Energy for Life

Carbohydrate Metabolism

Lipid and Amino Acid Metabolism

Body Fluids

Filters

_ _ is the characteristic of an enzyme that acts on only one substance.