Chapter 8: Energy, Enzymes and Metabolism

Question 1

energy

Answer 1

the capacity to do work, or capacity of change

Question 2

potential energy

Answer 2

stored energy– as chemical bonds, concentration gradient, charge imbalance, etc.

Question 3

kinetic energy

Answer 3

energy of movement

Question 4

metabolism

Answer 4

sum total of all chemical reactions in an organism

Question 5

anabolic reactions

Answer 5

complex molecules are made from simple molecules; energy input is required

Question 6

catabolic reactions

Answer 6

complex molecules are broken down to simpler ones; energy is released

Question 7

laws of thermodynamics

Answer 7

apply to all matter and all energy transformations in the universe

Question 8

first law of thermodynamics

Answer 8

energy is neither created or destroyed, when energy is converted total energy before and after conversion is the same.

Question 9

second law of thermodynamics

Answer 9

when energy is converted from one form to another, some energy becomes unavailable for work, no energy transformation is 100% efficient

Question 10

entropy

Answer 10

measure of disorder in a system

Question 11

total energy = free energy + unusable energy

Answer 11

enthalpy (H) = free energy (G) + entropy (S)

Question 12

change of energy in a reaction

Answer 12

△G = △H - T△S

Question 13

△G is negative

Answer 13

catabolic

Question 14

△G is positive

Answer 14

anabolic

Question 15

exergonic

Answer 15

reactions release free energy (-△G): Catabolism complexity decreases

Question 16

endergonic

Answer 16

reactions consume free energy (+△G): Anabolism complexity increases

Question 17

chemical equilibrium

Answer 17

△G=0

Question 18

catalysts

Answer 18

speed up the rate of a reactions, lower activation energy

Question 19

Activation Energy

Answer 19

amount of energy required to start a reaction

Question 20

transition state intermediates

Answer 20

activation energy changes reactants into unusable forms with higher free energy

Question 21

Enzyme Substrate Complex

Answer 21

held together by hydrogen bonds, electrical attraction, or covalent bonds
E + S ⇨ ES ⇨ E + P

Question 22

Acid Base Catalyst

Answer 22

enzyme side chains transfer H+ to or from substrate, causing a covalent bond to break

Question 23

covalent catalyst

Answer 23

functional group in a side chain bond covalently with substrate

Question 24

metal ion catalysts

Answer 24

metal on side chains lose or gain electrons

Question 25

cofactors

Answer 25

inorganic ions

Question 26

coenzymes

Answer 26

small carbon-containing molecules; not bound permanently to enzymes, requires for action of enzyme

Question 27

prosthetic groups

Answer 27

non-amino acid groups permenantly bound to enzymes

Question 28

inhibitors

Answer 28

molecules that bind to enzyme and slower reactions

Question 29

irreversible inhabitation

Answer 29

inhibitor covalently bonds to side chains in the active site--permanently inactivates the enzyme

Question 30

reversible inhibition

Answer 30

inhibitors bonds noncovalently to active site, prevents substrate from binding

Question 31

competitive inhibitors

Answer 31

complete with natural substrate for binding sites. when concentration of competitive inhibitor reduced

Question 32

noncompetitive inhibitors

Answer 32

bind to the enzyme at a different site. enzyme changes shape an alters the active site

Question 33

allosteric regulation

Answer 33

effector molecules binds to a regulatory subunit

Question 34

metabolic pathways

Answer 34

first reactions is commitment step-- other reactions then happen in sequence

Question 35

feedback inhibition

Answer 35

final product acts as a noncompetitive inhibitor of first enzyme which shuts down pathway