Chapter 8

Question 1

metabolism

Answer 1

totality of an organisms chemical reactions

Question 2

in a metabolic pathway

Answer 2

a specific molecule is altered in a series of defined steps, resulting in a certain product. each step is catalyzed by a specific enzyme, a macromolecule that speeds up a chemical reaction

Question 3

catabolic pathways

Answer 3

breakdown pathways

Question 4

anabolic pathways

Answer 4

consume energy to build complicated molecules from simple ones

Question 5

energy

Answer 5

capacity to cause change

Question 6

kinetic energy

Answer 6

energy associated with motion

Question 7

thermal energy

Answer 7

kinetic energy associated with the random movement of atoms or molecules

Question 8

potential energy

Answer 8

object not moving; energy an object has because of its position

Question 9

chemical energy

Answer 9

potential energy available for release

Question 10

thermodynamics

Answer 10

study of the energy transformations that occur in a collection of matter

Question 11

entropy

Answer 11

randomness

Question 12

free energy

Answer 12

portion of a systems energy that can perform work when temperature and pressure are uniform throughout the system

Question 13

exergonic reaction

Answer 13

net release of energy

Question 14

endergonic reaction

Answer 14

absorbs energy from surrounding

Question 15

energy coupling

Answer 15

the use of exergonic processes to drive an endergonic one

Question 16

enzyme

Answer 16

macromolecule that acts as a catalyst

Question 17

catalyst

Answer 17

chemical agent that speeds up a reaction without being consumed by the reaction

Question 18

activation energy

Answer 18

initial investment of energy for starting a reaction

Question 19

catalysis

Answer 19

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

Question 20

active site

Answer 20

typically a pocket or groove on the surface of the enzyme where catalysis occurs

Question 21

substrate

Answer 21

the reactant an enzyme acts on

Question 22

induced fit

Answer 22

the tightening of the binding after initial contact

Question 23

competitive inhibitors

Answer 23

reduce productivity of enzymes by blocking substrates from entering active sites

Question 24

allosteric regulation

Answer 24

any case in which a protein’s function at one site is affected by the binding of a regulatory molecule to a separate site

Question 25

feedback inhibition

Answer 25

a metabolic pathway is halted by the inhibitory binding of its end product to an enzyme that acts early in the pathway