Enzymes

Question 1

proteins that catalyze the biochemical reactions

Answer 1

enzymes

Question 2

enzymes catalyze reactions that ____________

Answer 2

break down food molecules to allow the cell to harvest energy.

Question 3

enzymes also catalyze the _________ reactions that produce the great variety of molecules required for __________.

Answer 3

biosynthetic

cellular life

Question 4

Although there are thousands of enzymes, they all may be organized within ____ classes based on the ______

Answer 4

six

type of reaction they catalyze

Question 5

what are the 6 enzymes classes

Answer 5

Oxidoreductases
Transferases
Hydrolases
Lyases
Isomerases
Ligases

Question 6

are enzymes that catalyze oxidation–reduction (redox) reactions.

Answer 6

Oxidoreductases

Question 7

is an oxidoreductase that removes hydrogen from a molecule of lactate.

Answer 7

Lactate dehydrogenase

Question 8

Other subclasses of the oxidoreductases include

Answer 8

oxidases and reductases.

Question 9

are enzymes that catalyze the transfer of functional groups from one molecule to another.

Answer 9

Transferases

Question 10

catalyzes the transfer of an amino functional group

Answer 10

transaminase

Question 11

catalyzes the transfer of a methyl group

Answer 11

transmethylase

Question 12

catalyzes the transfer of a phosphoryl group.

Answer 12

kinase

Question 13

play a major role in energy-harvesting processes involving ATP

Answer 13

Kinases

Question 14

is an enzyme that catalyzes the transfer of a phosphoryl group from adenosine triphosphate (ATP) to a molecule of glucose in the first reaction of glycolysis

Answer 14

Hexokinase

Question 15

Urease, a _____, catalyzes the reaction responsible for this smell of ___________

Answer 15

hydrolase

kitty litter

Question 16

______ catalyze hydrolysis reactions; that is, the addition of a water molecule to a bond, resulting in bond breakage.
These reactions are important in the ________

Answer 16

Hydrolases

digestive process

Question 17

_________, such as α-amylase, catalyze the hydrolysis of _______ bonds between __________ in a __________

Answer 17

glycosidases
glycosidic
monosaccharides
polysaccharide

Question 18

_______ catalyze the hydrolysis of _____ bonds in proteins to release _______

Answer 18

proteases
peptide
amino acids

Question 19

Lipases catalyze the _____ of the ester bonds in _________

Answer 19

hydrolysis

triglycerides

Question 20

catalyzes the transfer of a phosphoryl group.

Answer 20

kinase

Question 21

play a major role in energy-harvesting processes involving ATP

Answer 21

Kinases

Question 22

is an enzyme that catalyzes the transfer of a phosphoryl group from adenosine triphosphate (ATP) to a molecule of glucose in the first reaction of glycolysis

Answer 22

Hexokinase

Question 23

Urease, a _____, catalyzes the reaction responsible for this smell of ___________

Answer 23

hydrolase

kitty litter

Question 24

______ catalyze hydrolysis reactions; that is, the addition of a water molecule to a bond, resulting in bond breakage.
These reactions are important in the ________

Answer 24

Hydrolases

digestive process

Question 25

_________, such as α-amylase, catalyze the hydrolysis of _______ bonds between __________ in a __________

Answer 25

glycosidases glycosidic monosaccharides polysaccharide

Question 26

_______ catalyze the hydrolysis of _____ bonds in proteins to release _______

Answer 26

proteases peptide amino acids

Question 27

Lipases catalyze the _____ of the ester bonds in _________

Answer 27

hydrolysis | triglycerides

Question 28

_____is an example of a lyase. In the citric acid cycle, fumarase catalyzes the addition of a ____ molecule to the _______ of the substrate fumarate. The product is ____.

Answer 28

Fumarase water double bond malate

Question 29

catalyzes a far more complicated reaction in which we see the removal of a group and formation of a double bond.

Answer 29

Citrate lyase

Question 30

citrate lyase catalyzes the removal of _____

Answer 30

an acetyl group from a molecule of citrate

Question 31

citrate lyase catalyzes the removal of an acetyl group from a molecule of citrate. The products of this reaction include

Answer 31

oxaloacetate acetyl CoA ADP inorganic phosphate group (Pi)

Question 32

rearrange the functional groups within a molecule and catalyze the conversion of one isomer into another.

Answer 32

Isomerases

Question 33

converts one structural isomer, 3-phosphoglycerate, into another, 2-phosphoglycerate

Answer 33

phosphoglycerate mutase

Question 34

are enzymes that catalyze a reaction in which a C−C, C−S, C−O, or C−N bond is made or broken.

Answer 34

Ligases

Question 35

Ligases are enzymes that catalyze a reaction in which a C−C, C−S, C−O, or C−N bond is made or broken. This is accompanied by an

Answer 35

ATP-ADP interconversion

Question 36

DNA ligase catalyzes the joining of the ____ group of a nucleotide in a DNA strand with the _____ group of the adjacent nucleotide to form a ______ bond

Answer 36

hydroxyl phosphoryl phosphoester

Question 37

The common names for some enzymes are derived from the name of the ____, the reactant that binds to the enzyme and is converted into _____.

Answer 37

substrate | product

Question 38

In many cases, the name of the enzyme is simply derived by adding the suffix ___ to the name of the ___

Answer 38

-ase | substrate

Question 39

For instance, ____ catalyzes the hydrolysis of urea and ____ catalyzes the hydrolysis of the disaccharide lactose

Answer 39

urease | lactase

Question 40

______ catalyze the removal of hydrogen atoms from a substrate, while ______ catalyze the removal of carboxyl groups. Hydrogenases and carboxylases carry out the _____ reaction, adding hydrogen atoms or carboxyl groups to their _______-.

Answer 40

Dehydrogenases decarboxylases opposite substrates

Question 41

the systematic name of the oxidoreductase lactate dehydrogenase is

Answer 41

lactate: NAD oxidoreductase.

Question 42

How does an enzyme speed up a chemical reaction?

Answer 42

It changes the path by which the reaction occurs, providing a lower energy route for the conversion of the substrate into the product, the substance that results from the enzyme-catalyzed reaction.

Question 43

in short words how do enzymes speed up chemical reactions

Answer 43

enzymes speed up reactions by lowering the activation energy of the reaction.

Question 44

Recall that every chemical reaction is characterized by an

Answer 44

equilibrium constant

Question 45

This equilibrium constant is actually a reflection of the difference in

Answer 45

energy between reactants and products

Question 46

This equilibrium constant is actually a reflection of the difference in energy between reactants and products that is, a measure of the

Answer 46

relative stabilities of the reactants and products.

Question 47

No matter how the chemical reaction occurs (which path it follows), the difference in energy between the reactants and the products is always the

Answer 47

same

Question 48

an enzyme cannot alter the ________ for the reaction that it catalyzes.

Answer 48

equilibrium constant

Question 49

an enzyme can really only provide a __________ for the conversion of reactant to product and, in this way, ____up the reaction

Answer 49

lower energy path | speed

Question 50

The rates of uncatalyzed chemical reactions often _____ every time the substrate concentration is doubled

Answer 50

double

Question 51

as long as the substrate concentration increases, there is a

Answer 51

direct increase in the rate of the reaction

Question 52

Although the rate of the reaction is initially responsive to the substrate concentration, at a certain concentration of substrate the rate of the reaction reaches a _________

Answer 52

maximum value.

Question 53

the rate of the reaction initially increases rapidly as the substrate concentration is _____ but that the rate levels off at a ____________

Answer 53

increased | maximum value

Question 54

At its _______, the active sites of all the enzyme molecules are occupied by a ________.

Answer 54

maximum rate | substrate molecule

Question 55

is the region of the enzyme that specifically binds the substrate and catalyzes the reaction.

Answer 55

The active site

Question 56

A new molecule of substrate ____ bind to the enzyme molecule until the substrate molecule already held in the active site is ________________

Answer 56

cannot | converted to product and released.

Question 57

For an enzyme-catalyzed reaction, the rate is at a maximum when all of the enzyme molecules are bound to the _____ Beyond this concentration of substrate, further increases in substrate concentration have __________ rate of the reaction.

Answer 57

subtrate | no effect on the

Question 58

From this information, we realize that an enzyme-catalyzed reaction must occur in two stages: 1) The formation of an _________ This binding of the substrate to the active site of the enzyme is a __________ 2) Conversion of _____ into _____ and release of the ____ and ____. This step is ____ and ____ the rate of the overall reaction.

Answer 58

``` enzyme-substrate complex rapid step. substrate product product enzyme slower limits ```

Question 59

Stage 2 of the enzyme catalyzed reaction is called the __________

Answer 59

rate-limiting step

Question 60

why is it stage of the enzyme catalyzed reaction called the rate-limiting step

Answer 60

because the rate of the reaction is controlled, or limited, by the speed with which the substrate is converted into product and is released.

Question 61

Ultimately, the reaction rate is dependent on the

Answer 61

amount of enzyme that is available.