Ch 4 part 1 presentation

1. Ch. 4 The Energy of Life

3. 2 Forms of Energy
• Kinetic Energy • Potential energy

5. Sunlight
(kinetic
energy)
Heat
energy
Potential
energy
Chemical energy
(potential energy)
available for
cellular tasks
Heat
energy
Cellular
respiration Sugar
Photosynthesis
H2O
CO2
O2
Figure 4.2

7. 1st Law of Thermodynamics

8. 2nd Law of Thermodynamics

10. Chemical Reactions Sustain Life
• Metabolism
• Endergonic Reactions
• Exergonic Reactions

11. PotentialenergyofmoleculesPotentialenergyofmolecules
Products
Energy must
be supplied
Reactants
Energy
required
Energy in Energy in
Energy
released
Energy outEnergy out
Energy is
released
Products
Reactants
Progress of reaction
Progress of reaction
Carbon
dioxide
Water Glucose Oxygen
Oxygen Glucose Carbon
dioxide
Water
Exergonic reactions release energy; products contain less energy than reactants
Endergonic reactions require energy input; products contain more energy than reactants
Figure 4.4
6CO2 6H2O+ C6H12O6 6O2+
6O2 C6H12O6+ 6CO2 6H2O+

12. Electrons ( ) are transferred
from donor to acceptor
Electron acceptor
molecule
Electron donor
molecule
Oxidation
Oxidized molecule Reduced molecule
Reduction
e-
e-
Figure 4.5
Redox Reactions

14. Proteins of electron transport chain
Electron donor
(molecule being
oxidized)
Electron acceptor
(molecule being
reduced)
Energy
Energy
Energy Energy
Membrane
High Potential energy
of electrons
Low
Figure 4.6
e−e−

15. ATP = adenosine triphosphate

16. H2O
Energy
Hydrolysis
Figure 4.8
ADPATP
P P P
P
P P
ATP Hydrolysis

18. from exergonic
reactions
EnergyEnergy
for endergonic
reactions
ATP hydrolysis
ATP synthesis
Figure 4.9
ADP
ATP H2O
P+

19. Glucose
E.g., ATP provides the energy to build large molecules out of
small subunits
E.g., ATP binding changes shape of proteins involved in muscle
contraction
ATP energizes target molecule, making it more likely to bond
with other molecules.
ATP donates a phosphate group that changes the shape of
the target molecule.
Glucose
“activated”
by phosphate
group
Figure 4.10
Short polysaccharide Longer polysaccharide
Activated glucose
ATP ADP
P
P
P
PPATP ATP ADP ADP+ +

21. • Enzymes
• Activation Energy
• Active Site
• Cofactors

22. Products
Activation energy
required with enzyme
Potentialenergyofmolecules
Reactants
Activation energy
required without
enzyme
Net energy
released in
reaction
With enzyme
Without enzyme
Enzyme
Products
Enzyme-substrate complex
Substrate Active site
Enzyme
a.
b.
Figure 4.11

23. Enzyme from
human
Enzyme from
hot springs
bacterium
Low
High
Rateofreaction
Temperature (°C)
Human
body
37°C
30 40 50 60 70 80
Figure 4.12

24. Control of Reaction Rates
• Negative Feedback
• Noncompetitive Inhibition
• Competitive Inhibition
• Positive Feedback*

25. Substrate
Inhibitor
Enzyme
Competitive
inhibition
Noncompetitive
inhibition
Active site
Inhibitor
Normal
binding
Figure 4.14

26. Enzyme
1
Enzyme
2
Enzyme
3
Enzyme
4
Substrate Product
Negative feedback
Enzyme 4’s product inhibits
action of enzyme 1
Figure 4.13