Carl J Bernacchi

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• Carl J Bernacchi
• Illinois State Water Survey and
• Department of Plant Biology
• bernacch_at_uiuc.edu
• 217-333-8048
• Office Hours by Appointment
• 1408 IGB Building

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Thermodynamics and Metabolism

• By the end of this lecture you should be able to
• Describe the basic physical principles underlying
  cellular bioenergetics.
• Concepts and terms potential and kinetic
  energy, first and second laws of thermodynamics,
  free energy
•  Discuss the role of ATP as an energy carrier
  in cells.
• Concepts and terms nucleotide, ribose,
  phosphate groups, hydrolysis.
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• Describe the function of enzymes as biological
  catalysts.
• Concepts and terms active site, substrate,
  product, activation energy
• Discuss enzyme kinetics.
• Concepts and terms Vmax, Km
• Describe enzyme regulation.
• Concepts and terms competitive and
  noncompetitive inhibition, allosteric regulation,
  feedback inhibition  

Assigned reading Chapter 8 in the text book An
Introduction to Metabolism.
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Metabolism- Catabolic pathways breakdown
processes Anabolic pathways constructive
pathways
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Organisms transform energy The first law of
thermodynamics the energy of the universe is
constant energy can be transferred and
transformed, but can neither be created nor
destroyed. Conservation of energy. The second
law of thermodynamics every energy
transformation increase the entropy (disorder or
randomness) of the universe.
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Types of energy Kinetic energy Potential
energy
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The energy available to do work in a cell is
called free energy. G (free energy) H
(total energy) T (absolute T) S (entropy)
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For a reaction to occur spontaneously, H must
decrease, S must increase, or both must occur.
Spontaneous reactions have negative free
energy. DG Gfinal Ginitial spontaneous
reactions proceed if the change in free energy is
negative. At equilibrium DG 0.
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Respiration C6H12O6 6O2 ? 6CO2 6H20 DG
-686 kcal/mol an exergonic reaction. Exergonic
reactions Free energy out Endergonic reactions
Free energy in
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?G -7.3 kcal/mol
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• Some factors that affect the rate of enzyme
  catalyzed reactions
• substrate concentration
• temperature
• pH

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pH alters enzyme structure
Shoham et al. 1984 PNAS
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