chapter 8

Question 1

activation energy

Answer 1

the initial energy needed to break the bonds of reactants

Question 2

active site

Answer 2

the region on the enzyme that binds the substrate

Question 3

allosteric regulation

Answer 3

when a regulatory molecule binds to a protein at one site and affects the proteins function at another site

Question 4

anabolic pathways

Answer 4

consume energy to build complex molecules from simpler ones

Question 5

bioenergetics

Answer 5

the study of how energy flows through living organisms

Question 6

catabolic pathways

Answer 6

release energy by breaking down complex molecules into simpler compunds

Question 7

catalysis

Answer 7

the process by which a catalyst selectively speeds up a reaction without itself being consumed

Question 8

catalyst

Answer 8

chemical agent that speeds up a reaction without being consumed

Question 9

chemical energy

Answer 9

the potential energy available for release in a chemical reaction

Question 10

coenzymes

Answer 10

organic cofactors

Question 11

cofactors

Answer 11

nonprotein helpers that bind to the enzyme permanently or reversibly with substrate

Question 12

competitive inhibitors

Answer 12

closely resemble the substrate and can bind to the enzymes active site

Question 13

cooperativity

Answer 13

substrate binding to one active site triggering a shape change in the enzyme that stabilizes the active form for all other site

Question 14

endergonic reaction

Answer 14

absorbs free energy from the surroundings

Question 15

energy coupling

Answer 15

the use of an exergonic process to drive an endergonic one

Question 16

entropy

Answer 16

the measure of molecular disorder or randomness

Question 17

enzyme-substrate complex

Answer 17

when the enzyme and its substrate are bound, before the reaction commences

Question 18

exergonic reaction

Answer 18

energy outward proceeds with a net release of free energy to the surroundings

Question 19

feedback inhibition

Answer 19

the end product of a metabolic pathway suts down the pathway

Question 20

first law of thermodynamics

Answer 20

energy can be transferred and transformed but it cannot be created or destroyed

Question 21

free energy

Answer 21

the portion of a systems energy that can do work when temperature and pressure are uniform throughout the system (as in a living cell)

Question 22

induced fit

Answer 22

results from interactions between chemical groups on the substrate and the active site

Question 23

metabolic pathway

Answer 23

a specific molecule is altered in a series of steps to produce a product. each step is catalyzed by a specific enzyme

Question 24

metabolism

Answer 24

the totality of an organisms chemical reaction

Question 25

noncompetitive inhibition

Answer 25

bind to another part of the enzyme, away from the active site

Question 26

phosphorylated intermediate

Answer 26

the recipient molecule of phosphorylation, typically less stable with more free energy

Question 27

second law of thermodynamics

Answer 27

every energy transfer or transformation increases the entropy of the universe

Question 28

spontaneous processes

Answer 28

occur without energy input, they can happen slowly or quickly

Question 29

substrate

Answer 29

the reactant that an enzyme acts on

Question 30

thermodynamics

Answer 30

the study of energy transformations in a collection of matter