Biology 111 Chapter 8

Front 1

Metabolism

Back 1

Totality of an organism's chemical reactions

Front 2

Catabolic pathway

Back 2

Energy released

Front 3

Anabolic pathway

Back 3

Energy consumed

Front 4

Enzymes ___________ each step.

Back 4

accelerate

Front 5

Energy

Back 5

Capacity to cause change

Front 6

Heat energy

Back 6

A kind of kinetic energy

Front 7

Chemical energy

Back 7

Energy stored in molecules, a kind of potential energy

Front 8

Energy can be __________ from one form to another.

Back 8

converted

Front 9

During conversion process

Back 9

Energy is released

Front 10

First law of thermodynamics

Back 10

Energy can be transferred and transformed, but it cannot be created or destroyed

Front 11

Plants convert light to

Back 11

chemical energy

Front 12

Open systems

Back 12

A system that can transfer and transform energy

Front 13

Organisms are

Back 13

Open systems

Front 14

2nd law of thermodynamics

Back 14

Every energy transformation makes the universe more disordered

Front 15

Entropy

Back 15

Measures disorder/randomness

Front 16

More random a collection of matter,

Back 16

the greater its entropy

Front 17

Example of increasing entropy

Back 17

Breaking down glucose

Front 18

Symbol for entropy

Back 18

S

Front 19

Heat is a form of

Back 19

disorder

Front 20

Spontaneous processes

Back 20

Require no outside energy

Front 21

Spontaneous change can be

Back 21

Harnessed to do work

Front 22

Goal is to

Back 22

Increase stability

Front 23

Nonspontaneous processes

Back 23

Require energy to start

Front 24

Free energy

Back 24

Portion of a system's energy that is available to do work when temperature is uniform throughout system

Front 25

Free energy also

Back 25

Measures spontaneity and stability of a system

Front 26

Spontaneous systems high in

Back 26

free energy, unstable

Front 27

Spontaneous systems

Back 27

Move toward a more stable state

Front 28

In spontaneous processes,

Back 28

the free energy of a system decreases

Front 29

Symbol of free energy

Back 29

G

Front 30

Change in free energy from the start of a process until its finished

Back 30

G(final state) - G(starting state)

Front 31

For a system to be spontaneous

Back 31

Either give up energy, give up order, or both

Front 32

For a system to be spontaneous

Back 32

Change in G must be negative

Front 33

For a system to be spontaneous

Back 33

Change in S must be positive

Front 34

Spontaneous processes

Back 34

Catabolic pathway

Front 35

Maximum stability

Back 35

A system at equilibrium

Front 36

A cell at maximum stability is

Back 36

dead.

Front 37

Exergonic reaction

Back 37

Proceeds with a net release of free energy and change in G is negative

Front 38

Exergonic reaction

Back 38

Catabolic

Front 39

Example of exergonic reaction

Back 39

Breakdown of glucose

Front 40

In breakdown of glucose, change in G=

Back 40

-686 kcal/mol

Front 41

Endergonic reaction

Back 41

absorbs energy from surroundings.

Front 42

Endergonic reactions can

Back 42

store energy

Front 43

In an endergonic reactions,

Back 43

Change in G is positive

Front 44

Endergonic reaction

Back 44

Nonspontaneous

Front 45

Endergonic reaction example

Back 45

Photosynthesis

Front 46

Change in G in photosynthesis equals

Back 46

686 kcal/mol

Front 47

Cellular metabolism

Back 47

Cell uses thousands of exergonic and endergonic reactions

Front 48

Example of mechanical work

Back 48

Skeletal muscle contracting

Front 49

Example of transport work

Back 49

Moving solutes across membrane

Front 50

Example of chemical work

Back 50

Nonspontaneous processes

Front 51

ATP

Back 51

Immediate source of energy

Front 52

ATP

Back 52

Adenine triphosphate

Front 53

ATP is a

Back 53

Nucleotide

Front 54

Change in G of hydrolysis of ATP

Back 54

-7.3 kcal/mol

Front 55

ATP --------->

Back 55

ADP + P + energy

Front 56

Energy from hydrolysis of ATP

Back 56

coupled directly to endergonic processes

Front 57

After ATP is used,

Back 57

phosphate group moves to another molecule

Front 58

After ATP's phosphate group moves,

Back 58

molecule is now phosphorylated and more reactive

Front 59

Enzymes

Back 59

Catalyst

Front 60

Catalyst

Back 60

Changes rate of reaction without being consumed by reaction

Front 61

Enzyme

Back 61

Catalytic protein

Front 62

Enzymes ____________ movement of ______ through ___________.

Back 62

regulate, molecules, metabolic pathways

Front 63

Enzymes are a

Back 63

Exergonic reaction

Front 64

Activation energy (E sub A)

Back 64

Amount of energy needed to push reactants over an energy barrier, so the reaction can begin.

Front 65

Activation energy often in form of

Back 65

Heat

Front 66

Bonds of reactants break only when

Back 66

molecules have absorbed enough energy

Front 67

Transition state

Back 67

Waiting for molecules to absorb energy

Front 68

Difference between free energy of the reactants and the free energy of the products is the

Back 68

change of G

Front 69

Enzymes speed reactions by

Back 69

Lowering activation energy

Front 70

Enzymes do not

Back 70

Change change of G

Front 71

Enzymes simply

Back 71

hasten reactions that would occur eventually.

Front 72

Substrate

Back 72

Reactant which binds to an enzyme

Front 73

Enzyme catalyzes the

Back 73

Conversion of the substrate to product

Front 74

Sucrase is enzyme, binds to

Back 74

Sucrose

Front 75

Sucrose breaks disaccharide into

Back 75

Glucose and fructose

Front 76

Active site

Back 76

Area where substrate binds

Front 77

Substrate and enzyme binding

Back 77

Very specific

Front 78

Induced fit

Back 78

The substrate can only bind to a certain enzyme, and a certain enzyme can only bind to a certain substrate

Front 79

A single enzyme molecule can

Back 79

Catalyze tens of thousands of reactions a second

Front 80

A single enzyme molecule can

Back 80

Be reused

Front 81

A single enzyme molecule can

Back 81

Catalyze a reaction in the forward and reverse direction

Front 82

Rate enzymes can convert substrates to product depends on

Back 82

Substrate

Front 83

More substrate available,

Back 83

More frequently they can access active sites, speed up reaction

Front 84

Limit to how fact

Back 84

A reaction can occur with added substrate

Front 85

Enzyme saturation

Back 85

Active sites on all enzymes are engaged

Front 86

When enzyme saturation occurs,

Back 86

Add more enzyme

Front 87

3-D structure of enzymes (proteins)

Back 87

Depends on environmental conditions

Front 88

Changes in enzyme shape influence the

Back 88

Reaction rate

Front 89

Some conditions lead to ______________, and lead to ____________

Back 89

most active confrontation, optimal rate of reaction

Front 90

As temperature raises,

Back 90

Rate of reaction for an enzyme raises to a certain point

Front 91

If it reaches a certain temperature or pH,

Back 91

the enzyme denatures

Front 92

Optimal pH for most enzymes

Back 92

6-8

Front 93

Optimal pH for stomach enzymes

Back 93

2

Front 94

Optimal pH for intestine enzymes

Back 94

8

Front 95

Binding by inhibitors

Back 95

Prevents enzymes from catalyzing reactions

Front 96

Covalent bond between inhibitor and enzyme

Back 96

Irreversable

Front 97

Weak bond between inhibitor and enzyme

Back 97

Reversable

Front 98

Noncompetitive inhibition

Back 98

Inhibitor binds somewhere other than active site

Front 99

Competitive inhibition

Back 99

Inhibitor binds to active site

Front 100

Noncompetitive inhibition causes the enzyme to

Back 100

change shape, rendering active site unreceptive or less effective

Front 101

Allosteric site

Back 101

Area where noncompetitive inhibitor binds

Front 102

Regulatory site

Back 102

Area where noncompetitive inhibitor binds

Front 103

Negative feedback

Back 103

Metabolic pathway switched off by inhibitory binding of its end product to an enzyme that acts early in the pathway