ch 7: cellular respiration overview

• Cellular Respiration


  Process converting food molecules to energy (CO2, H2O)
• Lipids


  Organic molecules mainly composed of carbon and hydrogen
• Proteins


  Complex molecules made of amino acids
• Carbohydrates


  Sugars, starches, and fibers serving as energy sources
• Enthalpy


  ΔH: Energy difference in reactant and product bonds
• Entropy


  ΔS: Measure of disorder increase or decrease in reactions
• Spontaneous Reaction


  Process favored by both negative ΔH and positive ΔS
• Free-Energy Change


  ΔG: Measures spontaneity in reactions
• Metabolism


  All chemical reactions in an organism
• Exergonic


  Spontaneous reaction releasing free energy (negative ΔG)
• Endergonic


  Nonspontaneous reaction absorbing free energy (positive ΔG)
• Glycolysis


  10-step glucose breakdown producing pyruvate, ATP, and NADH· One molecule of glucose is converted to 2 molecules of pyruvate + energy (2 ATP and 2 NADH)·Occurs in the cytosol of all cells. Most others occur in the mitochondria.
• Hexokinase


  Enzyme in glycolysis step 1, requiring ATP
• Phosphofructokinase


  Enzyme in glycolysis step 3, requiring ATP and highly exergonic
• Pyruvate


  End product of glycolysis, further metabolized aerobically or anaerobically
• Acetyl-CoA


  Pyruvate converted for citric acid cycle entry
• Fermentation


  Metabolic process converting sugar to acids, gases, or alcohol
• Alcohol Fermentation


  Pyruvate converted to ethanol, releasing CO2
• Lactic Acid Fermentation


  Pyruvate reduced to lactate without CO2 release
• Efficiency


  Cellular respiration produces 38 ATP per glucose; fermentation produces 2 ATP
• Oxidative Metabolism


  Efficient, slow metabolic process
• Long-Distance Running


  Race pacing for sustained cellular respiration
• Digestion


  Breakdown of large molecules into smaller ones
• Catabolism


  Process of breaking down molecules for energy
• Energy Production


  Extraction of energy from oxidized fuel
• Acetyl-Coenzyme A


  Intermediate in food molecule breakdown
• Citric Acid Cycle


  Mitochondrial process oxidizing acetyl-group C atoms
• ATP Production


  Generation of ATP via electron-transport chain
• ATP


  Adenosine triphosphate, energy carrier molecule
• GTP


  Energy-storing molecule similar to ATP
• Oxidation-Reduction Reactions


  Metabolic reactions involving electron transfer
• Mitochondria


  Organelle for energy production via oxidative metabolism
• Citrate


  6-carbon molecule formed in citric acid cycle
• Isocitrate


  Isomer of citrate in citric acid cycle
• Succinate


  Product of succinyl-CoA oxidation in citric acid cycle
• Fumarate


  Result of succinate oxidation in citric acid cycle
• Malate


  Product of fumarate hydration in citric acid cycle
• Oxaloacetate


  Starting compound regenerated in citric acid cycle
• Respiratory Electron Transport System

  Array of carriers passing electrons for ATP production
• Electron-Transport Chain


  Series of oxidation-reduction reactions for ATP synthesis