CH 8

Question 1

Metabolism

Answer 1

-Totality of an organism’s chemical reactions

Question 2

Metabolic pathway

Answer 2

-Begins with a specific molecule ends with a product
-each step catalyzed by a specific enzyme

Question 3

Catabolic Pathways

Answer 3

-release energy by breaking down complex molecules into simpler compounds
-EX. cellular respiration

Question 4

Anabolic Pathways

Answer 4

-consume energy to build complex molecules from simpler ones
-EX. the synthesis of proteins from amino acids

Question 5

Bioenergetics

Answer 5

-the study of how energy flows through living organisms

Question 6

energy

Answer 6

-the capacity to cause change
-various forms, some can perform work

Question 7

Kinetic energy

Answer 7

-energy associated with motion

Question 8

Thermal energy

Answer 8

-kinetic energy associated with the random movement of atoms or molecules.

Question 9

Heat

Answer 9

-thermal energy in transfer between objects

Question 10

Potential energy

Answer 10

-energy that matter possesses because of location or structure

Question 11

Chemical energy

Answer 11

-potential energy available for release in a chemical reaction

Question 12

Thermodynamics

Answer 12

-the study of energy transformations

Question 13

isolated system

Answer 13

-unable to exchange energy or matter with surroundings
-EX. liquids in thermos

Question 14

open system

Answer 14

-energy and matter can be transferred between the system and its surroundings
-EX. organisms

Question 15

First law of thermodynamics (principle of conservation of energy)

Answer 15

-the energy of the universe is constant
-energy can be transferred and transformed but cannot be destroyed or created

Question 16

Second law of thermodynamics

Answer 16

-every energy transfer or transformation increases the entropy of the universe

Question 17

Entropy

Answer 17

-measure of molecular disorder, or randomness

Question 18

spontaneous processes

Answer 18

-occur without energy input
-can happen quickly or slowly
-must increase entropy in universe

Question 19

nonspontaneous processes

Answer 19

-decrease entropy
-will only occur if energy is provided

Question 20

Free energy

Answer 20

-energy that can do work when temperature and pressure are uniform

Question 21

Exergonic reaction

Answer 21

-proceeds with a net release of free energy and is spontaneous

Question 22

Endergonic reaction

Answer 22

-absorbs free energy from its surroundings and is nonspontaneous

Question 23

Energy coupling

Answer 23

-use of an exergonic process to drive an endergonic one
-cells use it to manage energy recourses
-mediated by ATP

Question 24

ATP (Adenosine triphosphate)

Answer 24

-cells energy shuttle
-composed of a ribose, adenine, and three phosphate groups

Question 25

phosphorylated intermediate

Answer 25

-recipient molecule

Question 26

Catalyst

Answer 26

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

Question 27

Enzyme

Answer 27

-a catalytic protein -EX. sucrase, an enzyme that catalyzes

Question 28

Activation energy

Answer 28

-the initial energy needed to start a chemical reaction -also called, the free energy of activation

Question 29

Catalysis

Answer 29

-enzymes or other catalysts speed up specific reactions by lowering activation energy

Question 30

Substrate

Answer 30

-reactant that an enzyme acts on

Question 31

Enzyme-substrate complex

Answer 31

when enzymes bind to its substrate

Question 32

Active site

Answer 32

-the region on the enzyme where the substrate binds

Question 33

Induced fit

Answer 33

-brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction

Question 34

Cofactors

Answer 34

-nonprotein enzyme helpers -may be inorganic or organic

Question 35

Coenzyme

Answer 35

-organic cofactor -EX. vitamins

Question 36

Competitive inhibitors

Answer 36

-binds to the active site of an enzyme, competing with the substance

Question 37

Noncompetitive inhibitors

Answer 37

-bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective

Question 38

Allosteric regulation

Answer 38

-may either inhibit or stimulate an enzyme's activity -occurs when a regulatory molecule binds to a protein at one site and affects the proteins function at another site

Question 39

Cooperativity

Answer 39

-form of Allosteric regulation that can amplify enzyme activity

Question 40

Feedback inhibition

Answer 40

-the end product of a metabolic pathway shuts down the pathway -prevents cells from wasting chemical resources by making more than needed