Exergonic vs. Endergonic Reactions

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Exergonic vs. Endergonic Reactions
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Energy Profile of an Exergonic Reaction
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Effect of Enzymes on Reaction Rates
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The Structure of ATP
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ATP and Work
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The ATP Cycle
ATP
catabolic pathways
anabolic pathways
Energy for cellular work (endergonic,
energy- consuming processes)
Energy from catabolism (exergonic, energy
yielding processes)
ADP P i
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Energy from Glycolysis
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NAD
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Lactic Acid Fermentation
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Alcohol Fermentation
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CLASS ACTIVITY

• Which kind of metabolic poison would most
  directly interfere with glycolysis?
• an agent that reacts with oxygen and depletes its
  concentration in the cell
• an agent that binds to pyruvate and inactivates
  it
• an agent that closely mimics the structure of
  glucose but is not metabolized
• an agent that reacts with NADH and oxidizes it to
  NAD
• an agent that inhibits the formation of acetyl
  coenzyme A

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Citric Acid Cycle
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Electron Transport Chain
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Electron Transport Chain
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ATP Synthase
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CLASS ACTIVITY

• Cyanide is a poison that blocks the passage
  of electrons along the electron transport chain.
  Which of the following is a metabolic effect of
  this poison?
• The lower pH of the intermembrane space is much
  lower than normal.
• Electrons are passed directly to oxygen, causing
  cells to explode.
• Alcohol would build up in the cells.
• NADH supplies would be exhausted, and ATP
  synthesis would cease.
• No proton gradient would be produced, and ATP
  synthesis would cease.

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Counting ATPs
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CAC The Metabolic Hub of the Cell
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CLASS ACTIVITY

• A young relative of yours has never had
  much energy. He goes to a doctor for help and is
  sent to the hospital for some tests. There they
  discover his mitochondria can use only fatty
  acids and amino acids for respiration, and his
  cells produce more lactate than normal. Of the
  following, which is the best explanation of his
  condition?
• His mitochondria lack the transport protein that
  moves pyruvate across the outer mitochondrial
  membrane.
• His cells can not move NADH from glycolysis into
  the mitochondria.
• His cells contain something that inhibits oxygen
  use in his mitochondria.
• His cells lack the enzyme in glycolysis that
  forms pyruvate.
• His cells have a defective electron transport
  chain, so glucose goes to lactate instead of to
  acetyl CoA.

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Control of Cellular Respiration