VITAMINS AND ENZYMES

Question 1

is an organic compound that acts as a catalyst for a biochemical reaction

Answer 1

Enzymes

Question 2

is an enzyme composed only of protein (amino acid chains).

Answer 2

simple enzyme

Question 3

is an enzyme that has a nonprotein part in addition to a protein part

Answer 3

conjugated enzyme

Question 4

is the nonprotein part of a conjugated enzyme. It is the combination of apoenzyme with a cofactor that produces a biochemically active enzyme

Answer 4

cofactor

Question 5

is the protein part of a conjugated enzyme.

Answer 5

apoenzyme

Question 6

is the biochemically active conjugated enzyme produced from an apoenzyme and a cofactor.

Answer 6

holoenzyme

Question 7

is a small organic molecule that serves as a cofactor in a conjugated enzyme.

Answer 7

coenzyme

Question 8

is the reactant in an enzyme-catalyzed reaction

Answer 8

substrate

Question 9

is an enzyme that catalyzes an oxidation–reduction reaction

Answer 9

oxidoreductase

Question 10

is an enzyme that catalyzes the transfer of a functional group from one molecule to another.

Answer 10

A transferase

Question 11

catalyzes the transfer of an amino group from one molecule
to another.

Answer 11

transaminase

Question 12

catalyze the transfer of a phosphate group from adenosine triphosphate (ATP) to give adenosine diphosphate (ADP) and a phosphorylated product (a
product containing an additional phosphate group).

Answer 12

Kinases

Question 13

is an enzyme that catalyzes a hydrolysis reaction in which the addition
of a water molecule to a bond causes the bond to break

Answer 13

hydrolase

Question 14

effect the breaking of peptide linkages in proteins, and lipases effect the breaking of ester linkages in triacylglycerols

Answer 14

proteases

Question 15

is an enzyme that catalyzes the addition of a group to a double bond or the
removal of a group to form a double bond in a manner that does not involve hydrolysis or oxidation

Answer 15

lyase

Question 16

effects the removal of the components of water from a double bond

Answer 16

dehydratase

Question 17

is an enzyme that catalyzes the isomerization (rearrangement of atoms)
of a substrate in a reaction, converting it into a molecule isomeric with itself

Answer 17

isomerase

Question 17

effects the addition of the components of water to a double bond.

Answer 17

hydratase

Question 18

is an enzyme that catalyzes the bonding together of two molecules into one
with the participation of ATP

Answer 18

ligase

Question 19

is the relatively small part of an enzyme’s structure that is actually involved in catalysis.

Answer 19

active site

Question 20

is the intermediate reaction species that is formed when a substrate binds to the active site of an enzyme

Answer 20

enzyme–substrate complex

Question 21

the active site in the enzyme has a fixed, rigid geometrical conformation.

Answer 21

Lock-and-Key Model

Question 22

allows for small changes in the shape or geometry of the active site of an enzyme to accommodate a substrate

Answer 22

The induced-fi t model

Question 23

an enzyme will catalyze a particular
reaction for only one substrate

Answer 23

Absolute Specificity

Question 24

an enzyme can distinguish between stereoisomers.

Answer 24

Stereochemical Specificity

Question 25

involves structurally similar compounds that have the same functional groups

Answer 25

Group Specificity

Question 26

involves a particular type of bond, irrespective of the structural features in the vicinity of the bond.

Answer 26

Linkage Specificity

Question 27

is a measure of the rate at which an enzyme converts substrate to products in a biochemical reaction

Answer 27

Enzyme activity

Question 28

is the temperature at which an enzyme exhibits maximum activity

Answer 28

Optimum temperature

Question 29

which is active in the stomach, functions best at a pH of 2.0

Answer 29

Pepsin

Question 30

which operates in the small intestine, functions best at a pH of 8.0

Answer 30

trypsin

Question 31

is the number of substrate molecules transformed per minute by one molecule of enzyme under optimum conditions of temperature, pH, and saturation.

Answer 31

turnover number

Question 32

Reaction rate increases with increasing enzyme concentration, assuming enzyme concentration is much lower than that of substrate.

Answer 32

Concentration of Enzyme

Question 33

is a substance that slows or stops the normal catalytic function of an enzyme by binding to it

Answer 33

enzyme inhibitor

Question 34

is a molecule that sufficiently resembles an enzyme substrate in shape and charge distribution that it can compete with the substrate for occupancy of the enzyme’s active site.

Answer 34

competitive enzyme inhibitor

Question 35

is a molecule that decreases enzyme activity by binding to a site on an enzyme other than the active site

Answer 35

noncompetitive enzyme inhibitor

Question 36

is a molecule that inactivates enzymes by forming a strong covalent bond to an amino acid side-chain group at the enzyme’s active site

Answer 36

irreversible enzyme inhibitor

Question 37

A molecule closely resembling the substrate. Binds to the active site and temporarily prevents substrates from occupying it, thus blocking the reaction

Answer 37

Competitive Enzyme Inhibitor

Question 38

A molecule that binds to a site on an enzyme that is not the active site. The normal substrate still occupies the active site but the enzyme cannot catalyze the reaction due to the presence of the Inhibitor

Answer 38

Noncompetitive Enzyme Inhibitor

Question 39

A molecule that forms a covalent bond to a part of the active site, permanently preventing substrates from occupying it.

Answer 39

irreversible Enzyme Inhibitor

Question 40

is an enzyme with two or more protein chains (quaternary structure) and two kinds of binding sites (substrate and regulator

Answer 40

allosteric enzyme

Question 41

increases enzyme activity; the shape of the active site is changed such that it can more readily accept substrate

Answer 41

positive regulator

Question 42

(a noncompetitive inhibitor) decreases enzyme activity; changes to the active site are such that substrate is less readily accepted

Answer 42

negative regulator

Question 43

is a process in which activation or inhibition of the fi rst reaction in a reaction sequence is controlled by a product of the reaction sequence.

Answer 43

Feedback control

Question 44

is an enzyme that catalyzes the breaking of peptide bonds that maintain the primary structure of a protein

Answer 44

proteolytic enzyme

Question 45

is the inactive precursor of a proteolytic enzyme.

Answer 45

A zymogen

Question 46

and the removal of the phosphate group from the enzyme is called

Answer 46

dephosphorylation

Question 47

The process of addition of the phosphate group to the enzyme is called

Answer 47

phosphorylation

Question 47

is a process in which enzyme activity is altered by covalently modifying the structure of the enzyme through attachment of a chemical group to or removal of a chemical group from a particular amino acid within the enzyme’s structure.

Answer 47

Covalent modification

Question 48

is a substance that kills bacteria or inhibits their growth

Answer 48

antibiotic