enzymes

Question 1

biological catalyst that functions to speed up the rate of a biological reaction, but is not altered or consumed in the reaction

Answer 1

enzyme

Question 2

energy needed for the reaction to go to completion

Answer 2

activation energy

Question 3

the substances upon which an enzyme acts

Answer 3

substrates

Question 4

the substances produced by chemical modification of substrates

Answer 4

products

Question 5

the specific region on/in an enzyme where substrates bind and where the catalytic reaction occurs

Answer 5

active site

Question 6

the unstable “energized” intermediate formed in an enzymatic reaction that has properties of both the substrate and the product

Answer 6

transition state

Question 7

three things enzymes do to lower the activation energy

Answer 7

orienting/holding substrates very close together
creating/stabilizing the transition state intermediate
facilitating the reaction via reactive amino acids in the active site

Question 8

the model that suggests the enzyme active site perfectly matches the shape of the substrate and so the enzyme allows only one substrate to bind to the active site

Answer 8

lock and key model

Question 9

model that suggests substrates fit to active site like a flexible hand in glove, the enzyme-substrate binding changes the shape of both the enzyme and the substrate to fit snugly

Answer 9

induced fit model

Question 10

catalyze oxidation-reduction reactions; add/remove electrons from its substrate

Answer 10

oxidoreductases

Question 11

transfer a functional group from one molecule to another

Answer 11

transferases

Question 12

cleave bonds by adding a water molecule

Answer 12

hydrolases

Question 13

remove functional groups via non-hydrolytic reactions

Answer 13

lyases

Question 14

catalyze rearrangements of functional groups within a molecule

Answer 14

isomerases

Question 15

use the energy from ATP hydrolysis to form bonds between two substrate molecules

Answer 15

ligases

Question 16

EC 1-6

Answer 16

1. oxidoreductases
2. transferases
3. hydrolases
4. lysases
5. isomerases
6. ligases

Question 17

loosely bound non-protein components of enzymes that assist in catalytic reactions

Answer 17

cofactor

Question 18

two main types of cofactor

Answer 18

organic and inoganic

Question 19

tightly bound non-protein components of proteins

Answer 19

prosthetic groups

Question 20

hydrolyzes cellulose, used as a digestive aid and in biofuel production

Answer 20

cellulase

Question 21

hydrolyzes collagen, promotes burn and would healing

Answer 21

collagenase

Question 22

hydrolyzes sucrose, used in the manufacture of soft-centered candy

Answer 22

intertase

Question 23

hydrolyzes lipids, used as a digestive aid and improves the flavor of cheese

Answer 23

lipase

Question 24

hydrolyzes pectin and clarifies fruit juice

Answer 24

pectinase

Question 25

hydrolyzes protein and used in detergents

Answer 25

protease

Question 26

the maximum possible velocity that a reaction can have at infinite substrate concentration

Answer 26

V max

Question 27

the half maximal velocity of a reaction

Answer 27

1/2 V max

Question 28

the substrate concentration at which the enzyme has half maximal velocity

Answer 28

Km

Question 29

which velocities are the most relevant

Answer 29

the initial velocities

Question 30

reaction velocities ____ with time

Answer 30

slow down

Question 31

three reasons why enzymes rarely operate at true V max

Answer 31

substrate in most cells is not high enough little or no regulation by substrate at V max substrate at Km is more realistic

Question 32

an indication of enzyme affinity for substrate

Answer 32

Km

Question 33

enzymes with ____ have greater substrate affinity

Answer 33

lower Km's

Question 34

what are the axis for the lineweaver-burk equation graph

Answer 34

x axis: 1/substrate conc. | y axis: 1/v

Question 35

the amount of enzyme that produces one mole of product per minute

Answer 35

enzyme unit

Question 36

amount of enzyme that produces one mole of product per second

Answer 36

katal

Question 37

micromoles of product formed per minute per mg protein

Answer 37

specific activity

Question 38

the number of substrate molecules converted to product per unit time by a single molecule of enzyme

Answer 38

turnover number (Vmax/[Enz])

Question 39

an estimate of how perfect the enzyme is or how well the enzyme performs when S is low

Answer 39

catalytic efficiency (Kcat/Km)