Chapter 4.2

Question 1

What are enzymes?

Answer 1

Speed the rates of metabolic reactions

Question 2

Most enzymes are

Answer 2

globular proteins that catalyze specific reactions in cells by lowering the activation energy required to start these reactions.

Question 3

Enzymes can speed

Answer 3

metabolic reactions by a factor of a million or more

Question 4

What is catalysis?

Answer 4

The acceleration of chemical reaction rate

Question 5

Enzymes are required in small amounts because

Answer 5

as they work, they are not consumed and can, therefore, function repeatdly

Question 6

What is a substrate?

Answer 6

Each enzyme type is specific, acting only on a particular type of molecule

Question 7

Substrate of an enzyme called catalase is

Answer 7

hydrogen peroxide, a toxic by-product of certain metabolic reactions

Question 8

What is lipase?

Answer 8

A lipid-splitting enzyme

Question 9

What is Protease?

Answer 9

A protein-splitting enzyme

Question 10

Amylase

Answer 10

A starch-splitting enzyme

Question 11

What can sucrase?

Answer 11

splits the sugar sucrose

Question 12

what is maltase?

Answer 12

splits the sugar maltose

Question 13

what is lactase?

Answer 13

splits the sugar lactose

Question 14

What is the active site on the enzyme molecule?

Answer 14

it temporality combines with parts of the substrate molecule, forming an enzyme-substrate complex

Question 15

Many enzyme-catalyzed reactions are

Answer 15

reversible

Question 16

The rate of an enzyme-catalyzed reaction depends partyle on

Answer 16

the number of enzyme and substrate molecules in the cell

Question 17

The reaction is faster if

Answer 17

the concentration of the enzyme or the concentration of the substrate increases

Question 18

Many enzymes become inactive at

Answer 18

45 Celsius

Question 19

Nearly all enzymes denature at

Answer 19

55 Celsius

Question 20

Metabolic PAthways lead

Answer 20

to the synthesis or breakdown of particular biochemicals.

Question 21

Rate-limiting enzyme

Answer 21

When increasing the substrate concentration no longer affects the reaction rate

Question 22

What is a cofactor?

Answer 22

Some enzymes become active only when they combine with a nonprotein component

Question 23

A cofactor helps

Answer 23

the active site fold into its appropriate conformation or helps bind the enzyme to its subtrate

Question 24

What is a coenzyme?

Answer 24

A cofactor that may be an ion of an element,

Question 25

Many coenzymes are

Answer 25

composed of vitamin molecules, or incorporate altered forms of vitamin molecules

Question 26

Vitamins are

Answer 26

essential organic molecules that human cells cannot synthesize and therefore must come from the diet