Metabolism: Energy and Enzymes

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Metabolism Energy and Enzymes
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Energy

• Ability to do work, change matter
• Kinetic energy in motion
• Potential stored energy
• Chemical energy (food)
• Mechanical energy (motion)

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Thermodynamics

• 2 Laws
• 1. Law of conservation of energy Energy cannot
  be created or destroyed, but it can be changed
  from one form to another (heat energy)
• 2. Energy cannot be changed from one form to
  another without a loss of usable energy.
• When heat is released, it is not longer available
  to do work, lost to the environment.
• Cells are 40 efficient, rest of energy is given
  off as heat

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Entropy

• Used to indicate the relative amount of
  disorganization in universe
• Every process that occurs in cells increases the
  total entropy of the universe.
• More organized less stable
• Clean room, more organized but less stable than a
  messy room
• entropy clip

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Metabolic reactions

• Metabolism
• Reactants products
• Free energy amount of available energy to do
  work after a chemical reaction has taken place
  (G)
• Exergonic reactions delta G is negative,
  products have less energy than the reactants,
  reaction is spontaneous, energy is released, ex.
  ATP breakdown
• Endergonic reactions delta G is positive and
  products have more free energy than the
  reactants. Can only take place if there is an
  input of energy.

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Adenosine Triphosphate

• Energy currency, universal, can be used in many
  different types of reactions.
• Composed of Adenine (nitrogen base), ribose sugar
  and 3 phosphate groups
• Uses of ATP
• Chemical work synthesize macromolecules
• Transport work pumps
• Mechanical work muscle contraction, cilia to
  beat, chromosomes to move.

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Coupling reactions

• Energy released by exergonic reactions drive
  endergonic reactions.
• ATP breakdown is exergonic

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Function of ATP

• Chemical work helps to synthesize
  macromolecules
• Transport work supplies energy for pumps across
  membrane
• Mechanical work supplies energy to do work,
  muscle contraction, cilia beat