1. A Simple Thought Experiment
Just think of the biochemistry that occurs when one E. coli cells becomes one billion cells in 48 hours from simple material contained in a solution.

2. Driving Forces for Natural Processes
Enthalpy
Tendency toward lowest energy state
Form stablest bonds
Entropy
Tendency to maximize randomness
Energy and order.

3. Enthalpy and Bond Strength
Enthalpy = ∆H = heat change at constant pressure
Units
cal/mole or joule/mole
1 cal = 4.18 joule
Sign
∆H is negative for a reaction that liberates heat
Heat is a form of energy.

4. Entropy and Randomness
This goes against the grain; must supply lots of energy to take 153 free amino acids and convert them into the ordered sequence that is in myoglobin.

5. Entropy and Randomness
Entropy = S = measure of randomness
cal/deg·mole
T∆S = change of randomness
For increased randomness, sign is “+”
Order versus randomness. Just think of the energy input that is required to convert the random biochemical facts in your mind into a metabolic chart - don’t let entropy overcome you.

6. “System” Definition
If your brain is a closed, you can not gain knowledge. Consider how your attitude influences what you can do.

7. “System” Definition
When isolated, you can exchange energy.

8. “System” Definition
When open, both mass and energy are exchanged in a system.

9. Cells and Organisms: Open Systems
Material exchange with surroundings
Fuels and nutrients in (glucose)
By-products out (CO2)
Energy exchange
Heat release (fermentation)
Light release (fireflies)
Light absorption (plants)
Life occurs in an open system.

10. 1st Law of Thermodynamics
Energy is conserved, but transduction is allowed
Transduction
Energy is conserved; can change forms.

11. 2nd Law of Thermodynamics
In all spontaneous processes, total entropy of the universe increases
Randomness increase. A fact of life, just look on how messy your room gets.

12. 2nd Law of Thermodynamics
∆Ssystem + ∆Ssurroundings = ∆Suniverse > 0
A cell (system) can decrease in entropy only if a greater increase in entropy occurs in surroundings
C6H12O6 + 6O2  6CO2 + 6H2O
complex simple
Balanced equation.

13. Entropy: A More Rigorous Definition
From statistical mechanics:
S = k lnW
k = Boltzmann constant = 1.3810–23 J/K
W = number of ways to arrange the system
S = 0 at absolute zero (-273ºC)
Definition.

14. Gibbs Free Energy Unifies 1st and 2nd laws ∆G ∆G = ∆H – T∆S
Useful work available in a process
∆G = ∆H – T∆S
∆H from 1st law
Kind and number of bonds
T∆S from 2nd law
Order of the system
Gibbs free energy connects the first and second laws of thermodynamics.