Dec 22, 2015
To energize or not to energize?
• What is energy anyway?
I. Energy
• A. definitions– 1. energy– 2. work– 3. thermal
energy
4. Types of energy
a. Kinetic energy
b. Potential energy
Potential vs. Kinetic Energy
5. Open vs. closed systems
6. Entropy
7. Types of chemical reactions
• a. endergonicstores energy
decreases entropy
not spontaneous
requires energy input
Biological example
7. Types of chemical reactions
b. Exergonic reactions
you know what to put here from the previous slide
8. Metabolism
What type of reaction is illustrated in the diagram below?
1. Anabolic
2. Exergonic
3. Catabolic
4. One that increases entropy
Fre
e en
erg
y (G
)
B. Laws of thermodynamics
• 1. First Law– Definition– Repurcussions
Plants, being autotrophs, create their own energy.
1. True
2. False
2. Second law of thermodynamics
• Energy conversions are not 100% effective
• When energy changes form, some energy is lost as waste heat
• Entropy is always increasing
Life creates order. The second law of thermodynamics says that disorder is always increasing. Do living systems violate the second law of thermodynamics?
1. Yes
2. No
3. I don’t know
Explanation of question
C. Importance of ATP
• Energy currency of cell• Produced in the
mitochondria and chloroplasts
• Used whenever the cell needs to perform work
Molecular Structure of ATP
II. Nature of chemical reactions-chaotic
A. Chaotidc
II. Nature of chemical reactions
• B. Sometimes a productive collision occurs– Powerful– Correctly oriented– Enough speed to
overcome electron repulsion
II. Nature of chemical reaction
• C. Transition state forms– Represents high energy state– Very unstable– Very short lived– Old bonds are broken – New bonds form
What type of reaction occurred in this reaction?
1. Catabolic
2. Dehydration
3. Hydrolysis
4. Ionic bond formation
5. Both 1 & 2
II. Nature of chemical reactions C. Types of chemical reactions
• Exergonic reaction Endergonic reaction• Energy coupling
III. Energetics of chemical reactions• A. Energy profile at room
temperature
III. Energetics of chemical reactions
• B. Tricks chemists play• add heat• stir• increase concentration of reactants• increase pressure on reactants• add a catalyst
Effect of heating a chemical reaction
Effect of increasing the reactants’ concentrations
IV. How Enzymes Work
A. Normally
B. Characteristics of enzyme function
C. Effect on energy dynamics
D. Molecules at biological temperatures
E. Analogy of Volkswagon on the hill