Enzymes

Question 1

They govern all chemical reactions in living organisms. They are specialized proteins that with fascinating precision and selectivity, catalyze metabolic reactions that store and release energy, make pigments in our hair and eyes, digest the food we eat, synthesize cellular building materials and protect us by repairing cellular damage and clotting our blood.

Answer 1

Enzymes

Question 2

Without this, most chemical reactions in biochemical systems would occur too slowly to produce adequate amounts of the substances needed for cells to function properly. In some cases, needed reactions would not occur at all without their presence.

Answer 2

enzymes

Question 3

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

Answer 3

Enzyme

Question 4

The word enzyme come from the greek word ____ - which means ___ and ____– which means ____.

Answer 4

en ; in
Zyme ; yeast

Question 5

Enzymes undergo _______ also, which means slightly alteration in pH, temperature or other proteins denaturants affect the enzyme
activity.

Answer 5

denaturation

Question 6

it is an enzyme composed only
protein (amino acid chains)

Answer 6

Simple Enzymes

Question 7

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

Answer 7

Conjugated Enzymes

Question 8

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

Answer 8

HOLOENZYME

Question 9

It is a non protein part of conjugated
enzyme.

Answer 9

Cofactor

Question 10

It is a protein part of a conjugated
enzyme.

Answer 10

Apoenzyme

Question 11

HOLOENZYME is the biochemically active conjugated enzyme produced from an ______ and a ______.

Answer 11

apoenzyme ; cofactor

Question 12

It is the reactant in an enzyme-catalyzed reaction ; is the substance upon which the enzyme acts.

Answer 12

Substrate

Question 13

Suffix ___ that identifies a substance as an enzyme.

Answer 13

–ase

Question 14

Suffix _____ are also digestive enzymes

Answer 14

in

Question 15

The type of reaction catalyzed by an enzyme is often noted with ___________.

Answer 15

prefix

Question 16

It is an enzyme that catalyzes an oxidation – reduction reaction.

Answer 16

OXIDOREDUCTASE

Question 17

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

Answer 17

TRANSFERASE

Question 18

Two major subtypes of transferases:

Answer 18

transaminases and kinases

Question 19

Transfer of an amino group between Substrates

Answer 19

transaminases

Question 20

Transfer of a phosphate group between substrates

Answer 20

kinases

Question 21

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

Answer 21

HYDROLASE

Question 22

hydrolysis of ester linkages in lipids.

Answer 22

Lipases

Question 23

hydrolysis of amide linkages in proteins

Answer 23

Proteases

Question 24

hydrolysis of sugar–phosphate ester bonds in nucleic acids

Answer 24

Nucleases

Question 25

hydrolysis of glycosidic bonds in carbohydrates

Answer 25

Carbohydrases

Question 26

hydrolysis of phosphate–ester bonds

Answer 26

Phosphatases

Question 27

It 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 27

LYASES

Question 28

removal of H2O from a substrate

Answer 28

Dehydratases

Question 29

removal of CO2 from a substrate

Answer 29

Decarboxylases

Question 30

removal of NH3 from a substrate

Answer 30

Deaminases

Question 31

addition of H2O to a substrate

Answer 31

Hydratases

Question 32

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

Answer 32

ISOMERASE

Question 33

conversion of D isomer to L isomer, or vice versa

Answer 33

Racemases

Question 34

transfer of a functional group from one position to another in the same molecule

Answer 34

Mutases

Question 35

is an enzyme that catalyzes the bonding together of 2 molecules into one with the participation of ATP.

Answer 35

LIGASE

Question 36

formation of new bond between two substrates, with participation of ATP

Answer 36

Synthetases

Question 37

formation of new bond between a substrate and CO2, with participation of ATP

Answer 37

Carboxylases

Question 38

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

Answer 38

Active site

Question 39

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

Answer 39

ENZYME-SUBSTRATE COMPLEX

Question 40

In this model, the active site in the enzyme has a fixed rigid geometrical conformation. Only substrate with a complementary geometry can be accommodated at such site.

Answer 40

lock and key model

Question 41

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

Answer 41

induced fit model

Question 42

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

Answer 42

Enzyme activity

Question 43

Factors that affects Enzyme activity

Answer 43

- Temperature - pH

Question 44

Enzymes exhibit different levels of selectivity or specificity for substrates.

Answer 44

1. Absolute specificity 2. Stereochemical specificity 3. Group specificity 4. Linkage specificity

Question 45

the enzyme will catalyze only one particular reaction.

Answer 45

Absolute specificity

Question 46

Because amino acid are chiral compounds L- Amino acid to L- amino acid

Answer 46

Stereochemical specificity

Question 47

similar compound with same functional group example carboxypeptidase. It cleaves amino acids one at a time from the carboxyl end of the peptide chain.

Answer 47

Group specificity

Question 48

involves a particular type of bond. Phosphatases hydrolyze phosphate-ester bond.

Answer 48

Linkage specificity

Question 49

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

Answer 49

INHIBITORS

Question 50

The rates of enzyme-catalyzed reactions can be decreased by a group of substance called ________

Answer 50

INHIBITORS

Question 51

Three modes by which inhibition takes place are considered:

Answer 51

1. Reversible Competitive Inhibition 2. Reversible Noncompetitive Inhibition 3. Irreversible Inhibition

Question 52

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 active site.

Answer 52

Competitive Enzyme Inhibitor

Question 53

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

Answer 53

Noncompetitive Enzyme Inhibitor

Question 54

This inhibitor binds to a site other than the active site; the normal substrate still binds to the active site but the enzyme cannot catalyze the reaction due to the presence of the inhibitor

Answer 54

noncompetitive inhibitor

Question 55

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

Answer 55

Irreversible Enzyme Inhibitor

Question 56

Substances that bind to an enzyme and stop or slow its normal catalytic activity

Answer 56

ENZYME INHIBITORS

Question 57

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

Answer 57

Competitive Enzyme Inhibitor

Question 58

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 58

Noncompetitive Enzyme Inhibitor

Question 59

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

Answer 59

Irreversible Enzyme Inhibitor