Question 1

The graph shows how the rate of an enzyme-catalyzed reaction depends on the variable x.Which of the following quantities could x most likely represent?

Accepted Answer

A) enzyme concentration 
B) energy 
C) temperature 
D) substrate concentration 
E) progress of reaction 
A) enzyme concentration 
B) energy 
C) temperature 
D) substrate concentration 
E) progress of reaction

Question 2

Chymotrypsin catalyzes the hydrolysis of dietary carbohydrates.

Accepted Answer

A) True 
 B)False

Question 3

Some enzymes require an additional nonprotein prosthetic group in order to function.What is the protein part of this combination called?

Accepted Answer

A) substrate 
B) apoenzyme 
C) effector 
D) cofactor 
E) holoenzyme 
A) substrate 
B) apoenzyme 
C) effector 
D) cofactor 
E) holoenzyme

Question 4

Many enzymes are regulated by having more than one binding site.What is the term used to describe these enzymes?

Accepted Answer

A) allosteric enzymes 
B) lipases 
C) proenzymes 
D) lyases 
E) isomerases 
A) allosteric enzymes 
B) lipases 
C) proenzymes 
D) lyases 
E) isomerases

Question 5

What term refers to an organic molecule that binds transiently to an enzyme and participates in the reaction by either accepting or donating a chemical group?

Accepted Answer

A) apoenzyme 
B) cofactor 
C) effector 
D) coenzyme 
E) analog 
A) apoenzyme 
B) cofactor 
C) effector 
D) coenzyme 
E) analog

Question 6

What is the effect of an enzyme on the equilibrium constant for the reaction it catalyzes?

Accepted Answer

A) It increases the equilibrium constant. 
B) It decreases the equilibrium constant. 
C) It may increase or decrease the equilibrium constant,depending upon the specific reaction. 
D) It makes the equilibrium constant numerically equal to the reaction rate. 
E) It has no effect on the equilibrium constant. 
A) It increases the equilibrium constant. 
B) It decreases the equilibrium constant. 
C) It may increase or decrease the equilibrium constant,depending upon the specific reaction. 
D) It makes the equilibrium constant numerically equal to the reaction rate. 
E) It has no effect on the equilibrium constant.

Question 7

Isomerases rearrange the functional groups within a molecule.

Accepted Answer

A) True 
 B)False

Question 8

What is the term for a molecule that is similar in structure and charge distribution to the substrate in an enzyme-catalyzed reaction?

Accepted Answer

A) effector 
B) transition state 
C) structural analog 
D) irreversible inhibitor 
E) noncompetitive inhibitor 
A) effector 
B) transition state 
C) structural analog 
D) irreversible inhibitor 
E) noncompetitive inhibitor

Question 9

What portion of an enzyme is in direct contact with the substrate?

Accepted Answer

A) the inert site 
B) the alpha site 
C) the beta site 
D) the delta site 
E) the active site 
A) the inert site 
B) the alpha site 
C) the beta site 
D) the delta site 
E) the active site

Question 10

Irreversible inhibitors bind very tightly,and sometimes covalently,to enzymes.

Accepted Answer

A) True 
 B)False

Question 11

About half of the 223 amino acids in the enzyme trypsin are hydrophobic.Where in the tertiary structure of this globular protein are these amino acids most likely to be found?

Accepted Answer

A) at the N-terminal end of the protein chain 
B) at the C-terminal end of the protein chain 
C) on the exterior surface of the folded protein 
D) in the interior of the folded protein 
E) in the active site of the enzyme 
A) at the N-terminal end of the protein chain 
B) at the C-terminal end of the protein chain 
C) on the exterior surface of the folded protein 
D) in the interior of the folded protein 
E) in the active site of the enzyme

Question 12

What term describes the pH at which an individual enzyme functions best?

Accepted Answer

A) isoelectric pH 
B) pH optimum 
C) physiological pH 
D) neutral pH 
E) zwitterion pH 
A) isoelectric pH 
B) pH optimum 
C) physiological pH 
D) neutral pH 
E) zwitterion pH

Question 13

What three structurally similar pancreatic serine proteases function to cleave certain peptide bonds in proteins?

Accepted Answer

A) pepsinogen,zymogen,and acetylcholinesterase 
B) pepsinogen,trypsin,and pepsin 
C) tryptophan,trypsin,and chymotrypsin 
D) trypsin,chymotrypsin,and elastase 
E) choline,tryptophan,and proline 
A) pepsinogen,zymogen,and acetylcholinesterase 
B) pepsinogen,trypsin,and pepsin 
C) tryptophan,trypsin,and chymotrypsin 
D) trypsin,chymotrypsin,and elastase 
E) choline,tryptophan,and proline

Question 14

The pancreatic enzymes trypsin,chymotrypsin,and elastase all hydrolyze peptide bonds on the carbonyl side of several different amino acids in a protein.What term best describes their enzyme specificity?

Accepted Answer

A) stereospecific 
B) peptide 
C) absolute 
D) linkage 
E) group 
A) stereospecific 
B) peptide 
C) absolute 
D) linkage 
E) group

Question 15

What class of enzymes catalyzes the following reaction?

Accepted Answer

A) hydrogenase 
B) catalase 
C) isomerase 
D) elastase 
E) lipase 
A) hydrogenase 
B) catalase 
C) isomerase 
D) elastase 
E) lipase

Question 16

What parameter of a reaction does an enzyme alter?

Accepted Answer

A) product structure 
B) activation energy 
C) pH 
D) temperature 
E) concentration 
A) product structure 
B) activation energy 
C) pH 
D) temperature 
E) concentration

Question 17

Most cellular enzymes work optimally at what pH?

Accepted Answer

A) 2 
B) 5 
C) 7 
D) 9 
E) 12 
A) 2 
B) 5 
C) 7 
D) 9 
E) 12

Question 18

Phenylketonuria (PKU)is an inherited disease caused by the inability to produce a properly working form of the enzyme phenylalanine hydroxylase.This enzyme catalyzes the conversion of the amino acid phenylalanine to the amino acid tyrosine by adding a hydroxyl group to the para position on the ring.Based on this information,what is the structure of tyrosine (Tyr)?

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
E) 
  
A) 
  
B) 
  
C) 
  
D) 
  
E)

Question 19

Which of the following statements concerning enzymes is FALSE?

Accepted Answer

A) Enzymes are the body's biological catalysts,increasing the rate of cellular reactions. 
B) Enzymes are usually globular proteins with flexible three-dimensional shapes. 
C) The reactant in an enzyme-catalyzed reaction is called a cofactor. 
D) The active site of an enzyme is where substrate binding and catalysis occur. 
E) Inhibitors are molecules that cause an enzyme to lose its activity. 
A) Enzymes are the body's biological catalysts,increasing the rate of cellular reactions. 
B) Enzymes are usually globular proteins with flexible three-dimensional shapes. 
C) The reactant in an enzyme-catalyzed reaction is called a cofactor. 
D) The active site of an enzyme is where substrate binding and catalysis occur. 
E) Inhibitors are molecules that cause an enzyme to lose its activity.

Question 20

Which of the following correctly describes pepsinogen?

Accepted Answer

A) It is the inactive form of the enzyme pepsin. 
B) It is the cofactor for the enzyme pepsin. 
C) It is the inhibitor of the enzyme pepsin. 
D) It is an isoenzyme of pepsin. 
E) It is the name of the reaction catalyzed by pepsin. 
A) It is the inactive form of the enzyme pepsin. 
B) It is the cofactor for the enzyme pepsin. 
C) It is the inhibitor of the enzyme pepsin. 
D) It is an isoenzyme of pepsin. 
E) It is the name of the reaction catalyzed by pepsin.

Exam 19: Enzymes

The graph shows how the rate of an enzyme-catalyzed reaction depends on the variable x.Which of the following quantities could x most likely represent?

Chymotrypsin catalyzes the hydrolysis of dietary carbohydrates.

Some enzymes require an additional nonprotein prosthetic group in order to function.What is the protein part of this combination called?

Many enzymes are regulated by having more than one binding site.What is the term used to describe these enzymes?

What term refers to an organic molecule that binds transiently to an enzyme and participates in the reaction by either accepting or donating a chemical group?

What is the effect of an enzyme on the equilibrium constant for the reaction it catalyzes?

Isomerases rearrange the functional groups within a molecule.

What is the term for a molecule that is similar in structure and charge distribution to the substrate in an enzyme-catalyzed reaction?

What portion of an enzyme is in direct contact with the substrate?

Irreversible inhibitors bind very tightly,and sometimes covalently,to enzymes.

About half of the 223 amino acids in the enzyme trypsin are hydrophobic.Where in the tertiary structure of this globular protein are these amino acids most likely to be found?

What term describes the pH at which an individual enzyme functions best?

What three structurally similar pancreatic serine proteases function to cleave certain peptide bonds in proteins?

The pancreatic enzymes trypsin,chymotrypsin,and elastase all hydrolyze peptide bonds on the carbonyl side of several different amino acids in a protein.What term best describes their enzyme specificity?

What class of enzymes catalyzes the following reaction?

What parameter of a reaction does an enzyme alter?

Most cellular enzymes work optimally at what pH?

Which of the following statements concerning enzymes is FALSE?

Which of the following correctly describes pepsinogen?

Chemistry - Methods and Measurement

The Structure of the Atom and the Periodic Table

Structure and Properties of Ionic and Covalent Compounds

Calculations, chemical Changes, and the Chemical Equation

States of Matter: Gases, liquids, and Solids

Solutions

Energy,rate and Equilibrium

Acids and Bases

The Nucleus, radioactivity, and Nuclear Medicine

An Introduction to Organic Chemistry

The Unsaturated Hydrocarbons: Alkenes, alkynes, and Aromatics

Alcohols, phenols, thiols, and Ethers

Aldehydes and Ketones

Carboxylic Acids and Carboxylic Acid Derivatives

Amines and Amides

Carbohydrates

Lipids and Their Functions in Biochemical Systems

Protein Structure and Function

Introduction to Molecular Genetics

Carbohydrate Metabolism

Aerobic Respiration and Energy Production

Fatty Acid Metabolism

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