chapter 13 section 1

Question 1

What is catalytic power?

Answer 1

The ratio of the enzyme-catalyzed rate to the uncatalyzed rate of a reaction.

Question 2

How much faster can enzymes catalyze reactions compared to uncatalyzed rates?

Answer 2

p to 10²⁶ times faster.

Question 3

Under what conditions do enzymes achieve their catalytic power?

Answer 3

Mild temperature and pH, in dilute aqueous solutions.

Question 4

Example of an enzyme with high catalytic power?

Answer 4

Jack bean urease.

Question 5

What is the relative catalytic power of urease?

Answer 5

About 10¹⁴.

Question 6

why is enzyme catalytic power remarkable compared to synthetic catalysts?

Answer 6

Enzymes achieve enormous rate acceleration under mild, aqueous conditions that synthetic catalysts cannot match.

Question 7

What does specificity refer to in enzymes?

Answer 7

The selectivity of an enzyme for its substrates and the reactions it catalyzes.

Question 8

What are substrates?

Answer 8

The substances upon which an enzyme acts.

Question 9

Why do enzyme-catalyzed reactions produce no wasteful by-products?

Answer 9

Because the enzyme channels the substrate into a specific reaction with high fidelity.

Question 10

What is the basis of enzyme specificity?

Answer 10

Molecular recognition through structural complementarity between enzyme and substrate.

Question 11

What is the active site?

Answer 11

The specific region of an enzyme where substrate binding and catalysis occur.

Question 12

Why is regulation of enzyme activity important?

Answer 12

It ensures metabolic reaction rates match cellular requirements.

Question 13

How is enzyme regulation achieved?

Answer 13

Through control of enzyme production and reversible interactions with inhibitors or activators.

Question 14

Why are enzymes versatile in their functions?

Answer 14

Because most enzymes are proteins, and protein structures are highly versatile.

Question 15

Why was a systematic enzyme nomenclature created?

Answer 15

Because historical names were confusing and inconsistent.

Question 15

How were enzymes traditionally named?

Answer 15

By adding “-ase” to the substrate name, e.g., urease, phosphatase.

Question 16

How are enzymes classified in the modern system?

Answer 16

By the reaction they catalyze, into six major classes, with subclasses and sub-subclasses.

Question 17

What does the Enzyme Commission (E.C.) number represent?

Answer 17

A four-number code specifying class, subclass, sub-subclass, and individual enzyme.

Question 18

What does the term “kinase” indicate?

Answer 18

An ATP-dependent phosphotransferase.

Question 19

Why do traditional enzyme names remain in use?

Answer 19

They are simpler and more convenient than the full E.C. classification.

Question 20

What are cofactors?

Answer 20

Nonprotein components required for enzyme activity, can be metal ions or organic molecules.

Question 21

What are coenzymes?

Answer 21

often vitamins or containing vitamin-derived groups, that participate in catalysis.

Question 22

What is a prosthetic group?

Answer 22

A tightly bound coenzyme, sometimes covalently attached, essential for enzyme function.

Question 23

What is a holoenzyme?

Answer 23

The complete, catalytically active enzyme with its prosthetic group.

Question 24

What is an apoenzyme?

Answer 24

The protein portion of an enzyme without its prosthetic group; catalytically inactive.

Question 25

Why are cofactors/coenzymes important?

Answer 25

They provide chemical functions that amino acid side chains alone cannot perform, often carrying functional groups during catalysis.