Thermodynamics and Biology

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Thermodynamics and Biology
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Content

1. Metabolism
2. Energy
3. Laws of Thermodynamics
4. Free Energy

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Metabolism

• A highly integrated network of chemical reactions
  to maintain life.
• Reactions occur in step-by-step sequences called
  metabolic pathways.

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Catabolism vs. Anabolism

• Catabolism

• Anabolism

• The process of breaking down compounds into
  smaller molecules to release energy

• The process of using energy to build large
  molecules

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Energy
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Potential Energy and Kinetic Energy
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What can cells do with energy?

1. Mechanical work (e.g. muscle contraction,
   cellular movement)
2. Chemical work (e.g. synthesis of biomolecules)
3. Electrochemical work (e.g. active transport of
   molecules and ions)

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Thermodynamics

• The study of energy changes.
• System is the region of the universe under study
  (e.g. biological processes).
• Surroundings are everything else in the universe.

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Open System vs. Closed System
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How much energy is available?

• First Law of Thermodynamics
• The total amount of energy in the universe
  remains constant. More energy cannot be created
  existing energy cannot vanish. It can only be
  converted from one form to another.

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Conservation of Mass and Energy
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Energy can be converted from one form to another.
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OK Go! Music Video

• http//www.youtube.com/watch?vqybUFnY7Y8w

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The One-Way Flow of Energy

• Energy of a system is constantly being lost to
  the surroundings as heat.
• Second Law of Thermodynamics
• Any organized system tends to become more and
  more disorganized over time.
• Entropy is a measure of the degree of a systems
  disorder.

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Entropy
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Entropy
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Entropy Demonstration
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Free Energy

• Free energy is the energy from a chemical
  reaction that is available to do work, denoted by
  G.
• G H TS
• H is the enthalpy or heat of reaction
• TS is an energy term related to the degree of
  disorder in the system

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Endergonic vs. Exergonic

• Endergonic Receives energy from the surroundings

• Exergonic releases energy to the surroundings

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