Chapter 9

Chapter 9 - Harvesting Chemical Energy • Principles of...

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Unformatted text preview: Harvesting Chemical Energy • Principles of Energy Harvest • Cellular Respiration • Related Pathways – Fermentation – Redox reactions – Slow release of electron energy – Glycolysis, Krebs Cycle, & ETC Trapping Light Energy • Energy flow – Light chemical – Chemical power – All to heat • Chemical recycling – Organic molecules are OXIDIZED – CO2 is REDUCED Electrons moving CLOSER to Oxygen Bond H-H C-H O-H H-F S-O C-O Al - C Diff in EN Negative atom Type of Bond 0.0 0.4 1.4 1.9 1.0 1.0 1.0 N/A C O F O O C Cl O C pure covalent (weakly) polar covalent polar covalent polar covalent polar covalent polar covalent polar covalent ionic ionic polar covalent Na - Cl 2.1 Mg - O 2.3 Mg - C 1.3 From nonpolar to polar, the electrons move to positions closer to oxygen (more electronegative atom). An electron looses energy as it shifts from a less electronegative atom to a more electronegative one. A redox reaction that relocates electrons closer to oxygen releases chemical energy that can do work. To reverse the process, energy must be added to pull an electron away from an atom. NAD+ is Oxidizing agent during respiration Accepts 2 electrons and a proton Electron transport chain FREE ENERGY • Glycolysis – – – – Cellular Respiration Sugar breaking [6 carbon to 3 carbon] Glucose to Pyruvate Make some NADH Substrate­level PO4n of ADP • Citric Acid Cycle (Kreb’s Cycle) • Electron transport chain & Chemiosmosis – Driven by the oxidation of food molecules – Oxidative PO4n of ADP – Helps make more NADH (reducing of NAD+) and FADH2 – Substrate­level PO4n of ADP Overview Invest 2 ATP Pay off 2 ATP Pyruvate converted to Acetyl CoA What are we doing here? • Producing – ATP? – NADH? – FADH2? – CO2? – H20? Facilitated Diffusion of H+ ions • Obvious difference in H+ ion concentration • Allows for diffusion of H+ via this ATP synthase • Proton motive force – Performing work – Providing the E for ATP synthesis What is the purpose of fermentation? What does it produce and why? ...
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Chapter 9 - Harvesting Chemical Energy • Principles of...

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