1. Energetics
Fueling Life

2. Energy takes various forms
MECHANICALL

3. Energy, regardless of the form, can exist in two states
potential
kinetic

4. Photosynthesis makes energy available to organisms
Radiant (light) energy transformed into
chemical (CH2O) energy

5. Energy is used for cell work

6. In chemical rxns, energy is transferred as atoms & bonds are rearranged aka metabolism
Ex: Redox rxns
‘oxidized’ because e are so attracted to O
bonds broken H is oxidized F is reduced new bonds made
electrons transferred
energy transferred
OIL RIG

7. Metabolism includes anabolic rxns energy in…
…complex, energy-rich molecules out

8. Anabolic rxns aka: Endergonic Rxns that build molecules
Ex: dehydration reactions; photosynthesis
Require a net input of energy
therefore not spontaneous
Energy is stored in the bonds of the molecule
aka: Endergonic
Greater energy
In products
Less energy in reactants

9. Metabolism includes catabolic rxns
simpler molecules generated; energy released

10. Catabolic rxns aka: Exergonic Rxns that break down molecules
EX: hydrolysis reactions;
respiration
Stored energy is released as bonds are broken
aka: Exergonic
Higher energy reactants
Lower energy products

11. Anabolism & Catabolism are linked
Food eaten
Useable energy + products used to make needed molecules
Energy and molecular products

12. Reactions for Life Reflect the Laws of Thermodynamics*
Despite creationist claims to the contrary, highly ordered life does not violate the second law of T. Because although we can use energy to create order her eon Earth, the over all randomness of the universe is increasing.
* The study of energy transformations

13. Energy amount is constant
The universe is a closed system regarding both energy and matter
Energy amount is constant
The energy into a rxn = the energy at completion

14. Ex: Photosynthesis Energy in = energy out Matter in = Matter out
Matter & energy are conserved

15. Energy form however, is not constant
Energy is transformed at every step

16. Free energy useful to life + Energized atoms not useful ____
heat
Free energy
This is why there are not 15 trophic levels in a food web
Free energy useful to life
+ Energized atoms not useful
____
= Total Energy

17. Second Law of Thermodynamics
• No physical process finishes with as much available, or useful, energy as it started with FREE ENERGY
Brownian motion
• unavailable energy reflects the random kinetic energy of molecules, allowed to spread out; ENTROPY
Entropy in a closed system can never decrease. As long as entropy is defined as unavailable energy,
• Often, this means that:
- the change in energy includes transformation to heat
- small molecules result from the break down of larger ones
- an ordered system becomes more disordered

18. Entropy happens it’s the Law!

19. QUANTIFYING ENERGY OR total energy = useable energy* + unusable energy
available for work random atomic motion
*point of interest for biologists OR
useable energy = total energy - unusable energy available for work random atomic motion

20. useable = total _ unuseable energy energy energy
This relationship can be used to determine the energy change of a rxn: exergonic or endergonic?
useable = total _ unuseable
energy energy energy
GIBBS
FREE ENERGY = ENTHALPY - ENTROPY
As entropy increases, free energy decreases

21. To Know Gibbs = entHalpy - (Temp K) diSorder
If G < 0, the reaction is exergonic; occurs spontaneously; disorder is increased G is negative
If G > 0, the reaction is endergonic; order/complexity is increased G is positive
requires coupling with an exergonic rxn* to drive the process
* usually ATP -> ADP + P
In other words, the energy released from one reaction (spontaneous ones) will, in effect, drive other reactions which are not energetically favored (non-spontaneous ones).

22. Energy released
Spontaneous
Exergonic
G is negative
Energy required
Non-spontaneous
Endergonic
G is positive

23. 2H2O2 -> 2H2O + 02 Building or breaking down molecules?
Decreasing or increasing complexity?
Catabolic or anabolic?
Energy stored or released?
Endergonic or exergonic?
Chemical reactions can be “coupled” together if they share intermediates. In this case, the overall Gibbs Free Energy change is simply the sum of the ∆G values for each reaction. Therefore, an unfavorable reaction (positive ∆G1) can be driven by a second, highly favorable reaction (negative ∆G2 where the magnitude of ∆G2 > magnitude of ∆G1). For example, the reaction of glucose with fructose to form sucrose has a ∆G value of +5.5 kcal/mole. Therefore, this reaction will not occur spontaneously. The breakdown of ATP to form ADP and inorganic phosphate has a ∆G value of -7.3 kcal/mole. These two reactions can be coupled together, so that glucose binds with ATP to form glucose-1-phosphate and ADP. The glucose-1-phosphate is then able to bond with fructose yielding sucrose and inorganic phosphate. The ∆G value of the coupled reaction is -1.8 kcal/mole, indicating that the reaction will occur spontaneously. This principle of coupling reactions to alter the change in Gibbs Free Energy is the basic principle behind all enzymatic action in biological organisms.[10
For a reaction that is not spontaneous ΔG is positive. This means that work must be done on the system (through some outside intervention) to force the non-spontaneous reaction to occur. The minimum work that must be done is given by ΔG. This tells us that in order to create order in the universe, our bodies must somehow do work to force non-spontaneous reactions to occur. Our bodies do this by consuming fuel that, when oxidized, provides excess Gibbs free energy with which to do work. By combining the oxygen we breathe with the food we eat, we can generate excess Gibbs free energy to force otherwise non-spontaneous reactions to occur.
Increasing or decreasing disorder?
Change in G positive or negative?
Spontaneous or coupled with ATP?

24. Building or breaking down molecules?
Decreasing or increasing complexity?
Catabolic or anabolic?
Energy stored or released?
Endergonic or exergonic?
Chemical reactions can be “coupled” together if they share intermediates. In this case, the overall Gibbs Free Energy change is simply the sum of the ∆G values for each reaction. Therefore, an unfavorable reaction (positive ∆G1) can be driven by a second, highly favorable reaction (negative ∆G2 where the magnitude of ∆G2 > magnitude of ∆G1). For example, the reaction of glucose with fructose to form sucrose has a ∆G value of +5.5 kcal/mole. Therefore, this reaction will not occur spontaneously. The breakdown of ATP to form ADP and inorganic phosphate has a ∆G value of -7.3 kcal/mole. These two reactions can be coupled together, so that glucose binds with ATP to form glucose-1-phosphate and ADP. The glucose-1-phosphate is then able to bond with fructose yielding sucrose and inorganic phosphate. The ∆G value of the coupled reaction is -1.8 kcal/mole, indicating that the reaction will occur spontaneously. This principle of coupling reactions to alter the change in Gibbs Free Energy is the basic principle behind all enzymatic action in biological organisms.[10
For a reaction that is not spontaneous ΔG is positive. This means that work must be done on the system (through some outside intervention) to force the non-spontaneous reaction to occur. The minimum work that must be done is given by ΔG. This tells us that in order to create order in the universe, our bodies must somehow do work to force non-spontaneous reactions to occur. Our bodies do this by consuming fuel that, when oxidized, provides excess Gibbs free energy with which to do work. By combining the oxygen we breathe with the food we eat, we can generate excess Gibbs free energy to force otherwise non-spontaneous reactions to occur.
Increasing or decreasing disorder?
Change in G positive or negative?
Spontaneous or coupled with ATPrxn?