Question 1

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 2

What is the classification of an enzyme that catalyzes the joining of two molecules?

Accepted Answer

A) kinase 
B) ligase 
C) oxidoreductase 
D) transferase 
E) hydrolase 
A) kinase 
B) ligase 
C) oxidoreductase 
D) transferase 
E) hydrolase

Question 3

The arrival of a nerve impulse at the end plate of the nerve axon results in an influx of what ion?

Accepted Answer

A) calcium 
B) sodium 
C) potassium 
D) bicarbonate 
E) phosphate 
A) calcium 
B) sodium 
C) potassium 
D) bicarbonate 
E) phosphate

Question 4

To which class of enzymes does an enzyme belong if it catalyzes the rearrangement of functional groups within a molecule?

Accepted Answer

A) oxidoreductases 
B) lyases 
C) ligases 
D) isomerases 
E) lyases and ligases are correct. 
A) oxidoreductases 
B) lyases 
C) ligases 
D) isomerases 
E) lyases and ligases are correct.

Question 5

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 6

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

Accepted Answer

A) True 
 B)False

Question 7

The vitamin biotin is a component of a coenzyme.

Accepted Answer

A) True 
 B)False

Question 8

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 9

The presence of an enzyme catalyst will affect the time taken for a reaction to reach equilibrium.

Accepted Answer

A) True 
 B)False

Question 10

In 1956, Christian de Duve discovered organelles in the cytoplasm of certain cells that have hydrolytic enzymes that destroy bacteria and viruses.What are these organelles called?

Accepted Answer

A) lysosomes 
B) mitochondria 
C) endosomes 
D) ribosomes 
E) nucleosomes 
A) lysosomes 
B) mitochondria 
C) endosomes 
D) ribosomes 
E) nucleosomes

Question 11

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 12

Acetylcholine is a neurotransmitter that transmits a signal from a nerve cell to a muscle cell, causing the muscle to contract.How is the neurotransmitter inactivated so that the muscle can relax?

Accepted Answer

A) It is denatured by the local pH and loses its active conformation. 
B) It is hydrolyzed by the enzyme acetylcholinesterase. 
C) It is taken up and stored by the muscle cells. 
D) It is dissolved in the blood and is transported through the circulatory system. 
E) All of the choices are correct. 
A) It is denatured by the local pH and loses its active conformation. 
B) It is hydrolyzed by the enzyme acetylcholinesterase. 
C) It is taken up and stored by the muscle cells. 
D) It is dissolved in the blood and is transported through the circulatory system. 
E) All of the choices are correct.

Question 13

HIV protease inhibitors block the activity of enzymes responsible for which of the following?

Accepted Answer

A) viral replication 
B) digestion 
C) oxygen transport 
D) antibiotic activity 
E) pain production 
A) viral replication 
B) digestion 
C) oxygen transport 
D) antibiotic activity 
E) pain production

Question 14

Which of the following is true for an enzyme catalyzed reaction?

Accepted Answer

A) The rate of the reaction will increase indefinitely with an increase in the substrate concentration. 
B) The rate of the reaction will increase with an increase in the substrate concentration until it reaches a maximum rate. 
C) The rate of the reaction will decrease as the substrate concentration increases. 
D) The rate of the reaction is unaffected by substrate concentration. 
E) The rate of the reaction decreases as the amount of enzyme available increases. 
A) The rate of the reaction will increase indefinitely with an increase in the substrate concentration. 
B) The rate of the reaction will increase with an increase in the substrate concentration until it reaches a maximum rate. 
C) The rate of the reaction will decrease as the substrate concentration increases. 
D) The rate of the reaction is unaffected by substrate concentration. 
E) The rate of the reaction decreases as the amount of enzyme available increases.

Question 15

Which of the following describes how an enzyme can affect the transition state in an enzyme-catalyzed reaction?

Accepted Answer

A) modifying the local pH by accepting or donating H+ ions 
B) placing stress on a bond in the substrate, making it easier to break 
C) bringing two reactants together in close proximity and in a suitable orientation for reaction 
D) None of the choices are correct. 
E) All of the choices are correct. 
A) modifying the local pH by accepting or donating H+ ions 
B) placing stress on a bond in the substrate, making it easier to break 
C) bringing two reactants together in close proximity and in a suitable orientation for reaction 
D) None of the choices are correct. 
E) All of the choices are correct.

Question 16

Which of the following is a medical use of enzymes?

Accepted Answer

A) enzyme assays to diagnose damage or disease to a particular organ or tissues 
B) injection of enzymes to counteract blood clots 
C) enzyme replacement therapy for missing or malfunctioning enzymes 
D) analytical reagents in the clinic laboratory 
E) All of the choices are correct. 
A) enzyme assays to diagnose damage or disease to a particular organ or tissues 
B) injection of enzymes to counteract blood clots 
C) enzyme replacement therapy for missing or malfunctioning enzymes 
D) analytical reagents in the clinic laboratory 
E) All of the choices are correct.

Question 17

To which class of enzymes would you assign an enzyme that carries out the dehydrogenation of its substrate?

Accepted Answer

A) oxidoreductases 
B) transferases 
C) lyases 
D) hydrolases 
E) All of the choices are correct. 
A) oxidoreductases 
B) transferases 
C) lyases 
D) hydrolases 
E) All of the choices are correct.

Question 18

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

Accepted Answer

A) apoenzyme 
B) effector 
C) mineral 
D) cofactor 
E) vitamin 
A) apoenzyme 
B) effector 
C) mineral 
D) cofactor 
E) vitamin

Question 19

Lactase is an enzyme that catalyzes the following reaction.Which statement describing this reaction is FALSE?

Accepted Answer

A) Lactose is the substrate in this reaction. 
B) Glucose is a product in this reaction. 
C) Galactose is a cofactor in this reaction. 
D) This reaction occurs in the active site of lactase. 
E) Lactase is a hydrolase enzyme. 
A) Lactose is the substrate in this reaction. 
B) Glucose is a product in this reaction. 
C) Galactose is a cofactor in this reaction. 
D) This reaction occurs in the active site of lactase. 
E) Lactase is a hydrolase enzyme.

Question 20

What is an allosteric enzyme?

Accepted Answer

A) an enzyme whose activity is regulated by the binding of a small effector molecule 
B) the inactive form of an enzyme 
C) an enzyme that has become denatured and can no longer catalyze reactions 
D) an enzyme that is bound to an inhibitor molecule 
E) an enzyme that catalyzes reactions in plants and animals, but not humans 
A) an enzyme whose activity is regulated by the binding of a small effector molecule 
B) the inactive form of an enzyme 
C) an enzyme that has become denatured and can no longer catalyze reactions 
D) an enzyme that is bound to an inhibitor molecule 
E) an enzyme that catalyzes reactions in plants and animals, but not humans

Exam 19: 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 classification of an enzyme that catalyzes the joining of two molecules?

The arrival of a nerve impulse at the end plate of the nerve axon results in an influx of what ion?

To which class of enzymes does an enzyme belong if it catalyzes the rearrangement of functional groups within a molecule?

What class of enzymes catalyzes the following reaction?

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

The vitamin biotin is a component of a coenzyme.

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

The presence of an enzyme catalyst will affect the time taken for a reaction to reach equilibrium.

In 1956, Christian de Duve discovered organelles in the cytoplasm of certain cells that have hydrolytic enzymes that destroy bacteria and viruses.What are these organelles called?

Most cellular enzymes work optimally at what pH?

Acetylcholine is a neurotransmitter that transmits a signal from a nerve cell to a muscle cell, causing the muscle to contract.How is the neurotransmitter inactivated so that the muscle can relax?

HIV protease inhibitors block the activity of enzymes responsible for which of the following?

Which of the following is true for an enzyme catalyzed reaction?

Which of the following describes how an enzyme can affect the transition state in an enzyme-catalyzed reaction?

Which of the following is a medical use of enzymes?

To which class of enzymes would you assign an enzyme that carries out the dehydrogenation of its substrate?

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

Lactase is an enzyme that catalyzes the following reaction.Which statement describing this reaction is FALSE?

What is an allosteric enzyme?

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 Saturated Hydrocarbons

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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