9. Figure 8.2
A diver has more potential
energy on the platform
than in the water.
Diving converts
potential energy to
kinetic energy.
Climbing up converts the kinetic
energy of muscle movement
to potential energy.
A diver has less potential
energy in the water
than on the platform.
22. Figure 8.5
• More free energy (higher G)
• Less stable
• Greater work capacity
In a spontaneous change
• The free energy of the system
decreases (∆G < 0)
• The system becomes more
stable
• The released free energy can
be harnessed to do work
• Less free energy (lower G)
• More stable
• Less work capacity
(a) Gravitational motion (b) Diffusion (c) Chemical reaction
24. Figure 8.6
(a) Exergonic reaction: energy released, spontaneous
(b) Endergonic reaction: energy required, nonspontaneous
Reactants
Energy
Products
Progress of the reaction
Amount of
energy
released
(∆G < 0)
Reactants
Energy
Products
Amount of
energy
required
(∆G > 0)
Progress of the reaction
FreeenergyFreeenergy
28. Figure 8.8
(a) The structure of ATP
Phosphate groups
Adenine
Ribose
Adenosine triphosphate (ATP)
Energy
Inorganic
phosphate
Adenosine diphosphate (ADP)
(b) The hydrolysis of ATP ΔG = -7.3 kcal/mol
33. Figure 8.10
Transport protein Solute
ATP
P P i
P iADP
P iADPATP
ATP
Solute transported
Vesicle Cytoskeletal track
Motor protein Protein and
vesicle moved
(b) Mechanical work: ATP binds noncovalently to motor
proteins and then is hydrolyzed.
(a) Transport work: ATP phosphorylates transport proteins.
35. Figure 8.11
Energy from
catabolism (exergonic,
energy-releasing
processes)
Energy for cellular
work (endergonic,
energy-consuming
processes)
ATP
ADP P i
H2O
45. Figure 8.15-3
Substrates
Substrates enter active site.
Enzyme-substrate
complex
Enzyme
Products
Substrates are held
in active site by weak
interactions.
Active site can
lower EA and speed
up a reaction.
Active
site is
available
for two new
substrate
molecules.
Products are
released.
Substrates are
converted to
products.
1
2
3
45
6
48. Figure 8.16
Optimal temperature for
typical human enzyme (37°C)
Optimal temperature for
enzyme of thermophilic
(heat-tolerant)
bacteria (77°C)
Temperature (°C)
(a) Optimal temperature for two enzymes
RateofreactionRateofreaction
120100806040200
0 1 2 3 4 5 6 7 8 9 10
pH
(b) Optimal pH for two enzymes
Optimal pH for pepsin
(stomach
enzyme)
Optimal pH for trypsin
(intestinal
enzyme)
57. Figure 8.19
Regulatory
site (one
of four)
(a) Allosteric activators and inhibitors
Allosteric enzyme
with four subunits
Active site
(one of four)
Active form
Activator
Stabilized active form
Oscillation
Non-
functional
active site
Inactive form
Inhibitor
Stabilized inactive
form
Inactive form
Substrate
Stabilized active
form
(b) Cooperativity: another type of allosteric activation
59. Figure 8.21
Active site
available
Isoleucine
used up by
cell
Feedback
inhibition
Active site of
enzyme 1 is
no longer able
to catalyze the
conversion
of threonine to
intermediate A;
pathway is
switched off. Isoleucine
binds to
allosteric
site.
Initial
substrate
(threonine)
Threonine
in active site
Enzyme 1
(threonine
deaminase)
Intermediate A
Intermediate B
Intermediate C
Intermediate D
Enzyme 2
Enzyme 3
Enzyme 4
Enzyme 5
End product
(isoleucine)
Editor's Notes
Figure 8.UN01 In-text figure, p. 142
Figure 8.2 Transformations between potential and kinetic energy.
Figure 8.3 The two laws of thermodynamics.
Figure 8.4 Order as a characteristic of life.
Figure 8.5 The relationship of free energy to stability, work capacity, and spontaneous change.
Figure 8.6 Free energy changes (G) in exergonic and endergonic reactions.
For the Cell Biology Video Space Filling Model of ATP (Adenosine Triphosphate), go to Animation and Video Files.
Figure 8.8 The structure and hydrolysis of adenosine triphosphate (ATP).
For the Cell Biology Video Stick Model of ATP (Adenosine Triphosphate), go to Animation and Video Files.
Figure 8.9 How ATP drives chemical work: Energy coupling using ATP hydrolysis.
Figure 8.10 How ATP drives transport and mechanical work.
Figure 8.11 The ATP cycle.
Figure 8.UN02 In-text figure, p. 152
Figure 8.12 Energy profile of an exergonic reaction.
Figure 8.13 The effect of an enzyme on activation energy.
For the Cell Biology Video Closure of Hexokinase via Induced Fit, go to Animation and Video Files.
Figure 8.14 Induced fit between an enzyme and its substrate.
Figure 8.15 The active site and catalytic cycle of an enzyme.