1

Question 1

Hydrolase

Answer 1

Hydrolysis (catabolic)

Question 2

Acetyl-CoA synthetase—combines acetate and coenzyme
A to form acetyl-CoA for the Krebs cycle

Answer 2

Ligase or Polymerase

Question 2

Lipase—breaks down lipid molecules

Answer 2

Hydrolase

Question 2

Phosphoglucoisomerase—converts glucose 6-phosphate
into fructose 6-phosphate during glycolysis

Answer 2

Isomerase

Question 2

Joining two or more chemicals together (anabolic)

Answer 2

Ligase or Polymerase

Question 2

Rearrangement of atoms within a molecule (neither catabolic
nor anabolic)

Answer 2

Isomerase

Question 2

Splitting a chemical into smaller parts without using
water (catabolic)

Answer 2

Lyase

Question 3

Fructose-1,6-bisphosphate aldolase—splits fructose
1,6-bisphosphate into G3P and DHAP

Answer 3

Lyase

Question 4

Lactic acid dehydrogenase—oxidizes lactic acid to form
pyruvic acid during fermentation

Answer 4

Oxidoreductase

Question 4

Transfer of electrons or hydrogen atoms from one molecule
to another

Answer 4

Oxidoreductase

Question 5

Moving a functional group from one molecule to another
(may be anabolic)

Answer 5

Transferase

Question 6

Hexokinase—transfers phosphate from ATP to glucose in
the first step of glycolysis

Answer 6

Transferase

Question 7

Type of Reaction Catalyzed

Answer 7

Moving a functional group from one molecule to another
(may be anabolic)

Question 8

breaks down lipid molecules

Answer 8

Lipase

Question 9

converts glucose 6-phosphate
into fructose 6-phosphate during glycolysis

Answer 9

Phosphoglucoisomerase

Question 10

combines acetate and coenzyme
A to form acetyl-CoA for the Krebs cycle

Answer 10

Acetyl-CoA synthetase—

Question 11

transfers phosphate from ATP to glucose in
the first step of glycolysis

Answer 11

Hexokinase

Question 11

splits fructose
1,6-bisphosphate into G3P and DHAP

Answer 11

Fructose-1,6-bisphosphate aldolase

Question 12

—oxidizes lactic acid to form
pyruvic acid during fermentation

Answer 12

Lactic acid dehydrogenase

Question 13

The shape of an enzyme’s functional site, called its _______ is complementary to the shape of the enzyme’s substrate

Answer 13

active site

Question 14

shapes and locations of only a few amino acids in a protein enzyme or nucleotides in a ribozyme determine the
shape of that enzyme’s active site.

Question 15

critical to enzyme
activity, has been likened to the fit between a lock and key

Answer 15

Enzyme-substrate specificity,

Question 16

almost as if a lock could grasp its key once it had been inserted. This
latter description of enhanced enzyme-substrate specificity is
called the_________

Answer 16

induced-fit model

Question 17

In some cases, several different enzymes possess active sites that are complementary to various portions of a single substrate molecule.

Question 18

In some cases, several different enzymes possess active sites that are complementary to various portions of a single substrate molecule. For example, an important precursor metabolite called ______________

Answer 18

phosphoenolpyruvic acid (PEP)

Question 18

In one catabolic pathway, PEP is converted to

Answer 18

pyruvic acid

Question 19

The enzyme and its substrate bind to form a temporary intermediate compound called an

Answer 19

n enzyme-substrate complex

Question 20

Bonds within the substrate are broken, forming_______ in catabolic reactions.

Answer 20

two or more products

Question 20

The binding of the substrate induces the enzyme to fit the shape of the substrate even more closely—the ________

Answer 20

induced-fit model.

Question 21

Many factors influence the rate of enzymatic reactions, including _____, _____, ______, _____, _____, ______

Answer 21

temperature, pH, enzyme and substrate concentrations, and the presence of inhibitors.

Question 22

The optimum temperature for the enzymes in the human body is ____, which is normal body temperature.

Answer 22

37°C

Question 23

The enzymes of some other microorganisms, however, function best at different temperatures; this is the case for ______, organisms that grow best at temperatures above 80°C.

Answer 23

hyperthermophiles

Question 24

If temperature rises beyond a certain critical point, the noncovalent bonds within an enzyme (such as the hydrogen bonds between amino acids) will break, and the enzyme will _____

Answer 24

denature

Question 25

Denaturation is said to be _____when an enzyme cannot regain its original structure once conditions return to normal

Answer 25

permanent

Question 26

In other cases, denaturation is _______ the denatured enzyme’s noncovalent bonds re-form on the return of normal conditions

Answer 26

reversible

Question 27

Rising temperature enhances enzymatic activity to a point, but above some optimal temperature an enzyme denatures and loses function

Question 28

) At lower substrate concentrations, enzyme activity increases as the substrate concentration increases and as more and more active sites are utilized.

Question 28

At the substrate concentration at which all active sites are utilized, termed the _______ enzymatic activity reaches a maximum, and any additional increase in substrate concentration has no effect on enzyme activity

Answer 28

saturation point,

Question 28

Enzymes typically have some optimal pH, at which point enzymatic activity reaches a maximum.

Question 29

______ provides a way to control the growth of unwanted microorganisms by denaturing their proteins

Answer 29

Changing the pH

Question 29

. Eventually, when all enzyme active sites have bound substrate, the enzymes have reached their_______, and the addition of more substrate _______ the rate of enzymatic activity

Answer 29

saturation point will not increase

Question 29

eukaryotic cells control some enzymatic activities by compartmentalizing enzymes inside membranes so that certain metabolic reactions proceed physically separated from the rest of the cell.

Question 30

An enzyme can be activated by the binding of a cofactor to the enzyme at a site located away from the active site a site called an_______

Answer 30

allosteric site

Question 31

the binding of an activator, such as a heavy-metal ion or other cofactor, to an allosteric site causes the enzyme’s active site to CHANGE THE SHAPE which activates the enzyme

Question 32

Substances that block enzyme activity are called_____

Answer 32

inhibitors

Question 33

______ are shaped such that they fit into an enzyme’s active site and thus prevent the normal substrate from binding

Answer 33

Competitive inhibitors

Question 34

Competitive inhibitors Such inhibitors do not undergo a chemical reaction to form products. Competitive inhibitors can bind permanently or reversibly to an active site

Question 35

reversible competition can be overcome by an increase in the_________, increasing the likelihood that active sites will be filled with substrate instead of inhibitor

Answer 35

concentration of substrate molecules

Question 36

________ can fill the active site of an enzyme required for the conversion of PABA into folic acid

Answer 36

Sulfanilamide

Question 37

do not attach to the active site but instead bind to an allosteric site on the enzyme

Answer 37

Noncompetitive inhibitors

Question 37

Cells often control the action of enzymes through feedback inhibition

Answer 37

feedback inhibition

Question 38

Electrons are transferred from an electron donor (a molecule that donates an electron) to an electron acceptor (a molecule that accepts an electron). Such electron transfers are called _______

Answer 38

oxidation-reduction reactions, or redox reactions

Question 38

oxidation involves______; reduction involves____

Answer 38

loss, gain

Question 39

In contrast, a molecule may be oxidized in one of three ways:

Answer 39

by losing a simple electron, by losing a hydrogen atom, or by gaining an oxygen atom.

Question 40

r. Three important electron carrier molecules are _____, ______,_____These molecules are derived from vitamins

Answer 40

nicotinamide adenine dinucleotide (NAD+), nicotinamide adenine dinucleotide phosphate (NADP+), and flavin adenine dinucleotide (FAD).

Question 41

. This happens by a general process called _______, in which inorganic phosphate is added to a substrate

Answer 41

phosphorylation

Question 42

Why is ATP well suited to serve as the primary short-term energy carrier in metabolic pathways?

Answer 42

First, it is multifunctional as a ribonucleotide for use in synthesizing RNA. Second, it is highly water soluble and can accumulate to high concentrations in cells with no ill effects. Third, it has two different levels of energy

Question 43

which involves the transfer of phosphate to ADP from another phosphorylated organic compound

Answer 43

* Substrate-level phosphorylation

Question 43

in which energy from redox reactions of respiration (described shortly) is used to attach inorganic phosphate to ADP

Answer 43

Oxidative phosphorylation

Question 43

______ which are chemicals that increase the likelihood of a reaction but are not permanently changed in the process

Answer 43

catalysts,

Question 44

in which light energy is used to phosphorylate ADP with inorganic phosphate

Answer 44

* Photophosphorylation

Question 44

Organic catalysts are known as ______

Answer 44

enzymes.

Question 45

______are inactive if they are not bound to one or more of the nonprotein substances called _____

Answer 45

Apoenzymes cofactors