Biology Campbell Chapter 8 Def. And Concepts

Front 1

Concept 8.1

Back 1

An organism's metabolism transforms matter and energy, subject to the laws of thermodynamics.

Front 2

Chapter 8

Back 2

An Introduction to Metabolism

Front 3

Organization of the Chemistry of Life into Metabolic Pathways

Back 3

Sub-Heading

Front 4

Metabolism

Back 4

The totality of an organism's chemical reactions. An emergent property of life that arises from interactions between molecules within the orderly environment of the cell.

Front 5

Metabolic Pathway

Back 5

Begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product. Each step of the pathway is catalyzed by a specific enzyme.

Front 6

Catabolic Pathways

Back 6

A metabolic pathway that releases energy by breaking down complex molecules to simpler compounds. Ex. Cellular respiration, in which the sugar glucose and other organic fuels are broken down in the presence of oxygen to carbon dioxide and water.

Front 7

Anabolic Pathways

Back 7

A metabolic pathway that consumes energy to synthesize a complex molecule from simpler compounds. Ex. The synthesis of a protein from amino acids.

Front 8

Bioenergetics

Back 8

The study of how energy flows through living organisms.

Front 9

Forms of Energy

Back 9

Sub-Heading

Front 10

Energy

Back 10

The capacity to cause change.

Front 11

Kinetic Energy

Back 11

Energy that can be associated with the relative motion of objects. Ex. A pool player uses the motion of the cue stick to push the cue ball, which in turn moves the other balls.

Front 12

Heat
(Thermal Energy)

Back 12

The total amount of kinetic energy due to the random motion of atoms or molecules in a body of matter. Energy in its most random form.

Front 13

Potential Energy

Back 13

Energy that matter possesses because of its location or structure. Energy that is not kinetic. Ex. Water behind a dam possesses energy because of its altitude above sea level.

Front 14

Chemical Energy

Back 14

The potential energy available for release in a chemical reaction. Ex. Complex molecule, such a glucose, are high in chemical energy because catabolic pathways release energy by breaking down complex molecules.

Front 15

The Laws of Energy Transformation

Back 15

Sub-Heading

Front 16

Thermodynamics

Back 16

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

Front 17

System

Back 17

The matter under study.

Front 18

Isolated System

Back 18

Unable to exchange either energy or matter with its surroundings.

Front 19

Surroundings

Back 19

Everything outside the system.

Front 20

Open System

Back 20

Energy and matter can be transferred between the system and its surroundings. Organisms are open systems.

Front 21

The First Law of Thermodynamics

Back 21

Sub-Heading

Front 22

First Law of Thermodynamics

Back 22

Energy can be transferred and transformed, but it cannot be created or destroyed. Also known as the principle of conservation of energy.Ex. The electric company does not make energy, but merely converts it to a form that is convenient for us to use.

Front 23

The Second Law of Thermodynamics

Back 23

Sub-Heading

Front 24

Entropy

Back 24

A measure of disorder, or randomness. Ex. As a cheetah converts chemical energy to kinetic energy, it is also increasing the disorder of its surroundings by producing heat and the small molecules, such as the CO₂ it exhales, that are the breakdown products of food.

Front 25

Second Law of Thermodynamics

Back 25

Every energy transfer or transaction increases the entropy of the universe. Ex. Only a small fraction of the chemical energy from food is transformed into the motion of a cheetah; most is lost as heat, which dissipates rapidly through the surroundings.

Front 26

Spontaneous

Back 26

A process that can occur without an input of energy. Does not imply that such a process would occur quickly. Ex. An explosion or rusting of an old car over time.

Front 27

Biological Order and Disorder

Back 27

Sub-Heading

Front 28

Concept 8.2

Back 28

The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously.

Front 29

Free-Energy Change, ∆G

Back 29

Sub-Heading

Front 30

Willard Gibbs

Back 30

A professor at Yale, defined a very useful function called the Gibbs free energy of a system (without considering its surroundings).

Front 31

Free Energy

Back 31

The portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell.

Front 32

Change in Free Energy Formula

Back 32

∆G = ∆H - T∆S
This formula uses only properties of the system (the reaction) itself: ∆H symbolizes the change in the system's enthalpy (in biological systems, equivalent to total energy); ∆S is the change in the system's entropy; and T is the absolute temperature in Kelvin (K) (K = C + 273)

Front 33

Free Energy, Stability, and Equilibrium

Back 33

Sub-Heading

Front 34

Change in Free Energy

Back 34

∆G = G(final state) - G(initial state)

Front 35

Equilibrium

Back 35

A state of maximum stability.

Front 36

Free Energy and Metabolism

Back 36

Sub-Heading

Front 37

Exergonic and Endergonic Reactions in Metabolism

Back 37

Sub-Heading

Front 38

Exergonic Reaction

Back 38

Proceeds with a net release of free energy.

Front 39

Endergonic Reaction

Back 39

Absorbs free energy form its surroundings.

Front 40

Equilibrium and Metabolism

Back 40

Sub-Heading

Front 41

Concept 8.3

Back 41

ATP powers cellular work by coupling exergonic reactions to endergonic reactions.

Front 42

Chemical Work

Back 42

The pushing of endergonic reactions, which would not occur spontaneously, such as the synthesis of polymers from monomers.

Front 43

Transport Work

Back 43

The pumping of substances across membranes against the direction of spontaneous movement.

Front 44

Mechanical Work

Back 44

Such as the beating of cilia, the contraction of muscle cells, and the movement of chromosomes during cellular reproduction.

Front 45

Energy Coupling

Back 45

The use of an exergonic process to drive and endergonic one.

Front 46

The Structure and Hydrolysis of ATP

Back 46

Sub-Heading

Front 47

ATP
(adenosine triphosphate)

Back 47

An adenine-containing nucleoside triposphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

Front 48

How ATP Performs Work

Back 48

Sub-Heading

Front 49

Phosphorylated

Back 49

The recipient of the phosphate group.

Front 50

The Regeneration of ATP

Back 50

Sub-Heading

Front 51

Concept 8.4

Back 51

Enzymes speed up metabolic reactions by lowering energy barriers.

Front 52

Enzyme

Back 52

A macromolecule that acts as a catalyst.

Front 53

Catalyst

Back 53

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

Front 54

The Activation Energy Barrier

Back 54

Sub-Heading

Front 55

Activation Energy

Back 55

The initial investment of energy for starting a reaction.

Front 56

How Enzymes Lower the Ea Barrier

Back 56

Sub-Heading

Front 57

Substrate Specificity of Enzymes

Back 57

Sub-Heading

Front 58

Substrate

Back 58

The reactant an enzyme acts on.

Front 59

Enzyme-Substrate Complex

Back 59

The enzyme binds to its substrate (or substrates, when there are two or more reactants).

Front 60

Active Site

Back 60

A pocket or groove on the surface of the protein where catalysis occurs.

Front 61

Induced Fit

Back 61

Brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction.

Front 62

Catalysis in the Enzyme's Active Site

Back 62

Sub-Heading

Front 63

Effects of Local Conditions on Enzyme Activity

Back 63

Sub-Heading

Front 64

Effects of Temperature and pH

Back 64

Sub-Heading

Front 65

Optimal Conditions

Back 65

Favor the most active shape for the enzyme molecule.

Front 66

Cofactors

Back 66

Sub-Heading

Front 67

Cofactors

Back 67

May be bound tightly to the enzyme as permanent residents, or they may bind loosely and reversibly along with the substrate.

Front 68

Coenzyme

Back 68

If the the cofactor is an organic molecule.

Front 69

Enzyme Inhibitor

Back 69

Sub-Heading

Front 70

Competitive Inhibitors

Back 70

Reduce the productivity of enzymes by blocking substrates from entering active sites.

Front 71

Noncompetitive Inhibitors

Back 71

Do not directly compete with the substrate to bind to the enzyme at the active site.

Front 72

Concept 8.5

Back 72

Regulation of enzyme activity helps control metabolism

Front 73

Allosteric Regulation of Enzymes

Back 73

Sub-Heading

Front 74

Allosteric Regulation

Back 74

The term used to describe any case in which a protein's function at one site is affected by the binding of a regulatory molecule to a separate site.

Front 75

Allosteric Activation and Inhibition

Back 75

Sub-Heading

Front 76

Cooperativity

Back 76

This mechanism amplifies the response of enzymes to substrates: One substrate molecule primes an enzyme to accept additional substrate molecules more readily.

Front 77

Indentification of Allosteric Regulators

Back 77

Sub-Heading

Front 78

Feedback Inhibition

Back 78

Sub-Heading

Front 79

Feedback Inhibition

Back 79

A metabolic pathway is switched off by the inhibitory binding of its end product to an enzyme that acts early in the pathway.

Front 80

Specific Localization of Enzyme Within the Cell

Back 80

Sub-Heading