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Unformatted text preview: Cellular Respiration (8%) I. Reactions a. Endothermic Endothermic Endothermic: Enthalpy: (a): (b): Heat energy taken in from surroundings turned into potential energy in the products Products > Reactants The activation energy (Ea) for the forward reaction The activation energy (Ea) for the reverse reaction b. Exothermic Exothermic: Enthalpy: (a): (b): Exothermic
Reactantʹs potential energy or enthalpy is released into the surroundings, usually in the form of heat Products < Reactants The activation energy (Ea) for the forward reaction The activation energy (Ea) for the reverse reaction c. Enzymes (Covered in Week 1) II. Organism Synthesization i. Autotrophs 1. synthesize their own organize molecules 2. use sunlight to perform chemical reactions ii. Heterorophs 1. ingest organic molecules created by an outside source 2. humans III. Cellular Respiration (4‐step process) a. Glycolysis 1 i. Anaerobic (No Oxygen) ii. Glucose Pyruvate iii. Result: 2 ATP, 2 NADH 1. No Oxygen Present a. Fermentation i. Changes Pyruvate ii. Converts NADH NAD+ iii. Allows Glycolysis to continue iv. Output comparison Anaerobic (Fermentation) Aerobic 2 ATP 32‐36 ATP v. Yeast and some bacteria 1. CO2 and Ethanol vi. Animals 1. Lactic Acid FOR EUKARYOTIC CELLS ENTER MITOCHONDRIA FOR PROKARYOTIC CELLS CONTINUE IN CYTOPLASM b. Pyruvate Oxidation 2 i. Pyruvate Acetyl CoA ii. Result: 1 CO2, 1 NADH 1. Proteins, Nucleic Acids, and Lipids CAN be broken down to form Acetyl CoA c. Citric Acid Cycle (Krebs Cycle) 3 i. Acetyl CoA goes through molecular changes ii. Result: NADH, FADH2, CO2 d. Electron Transport Chain (Oxidative Phosphorylation) 4 Inner Mitochondrial Space Membrane NADH FADH2 Electron Transport Chain H+ H+ H+ Intracellular Matrix Electron Carriers Cytochromes H+ H+ H+ H+ H+ Protons NADH FADH2 H + H + H + O2 H2O H+ ATP Synthase ATP Flow of Electrons Flow of Protons (H+) i. Flow of Electrons 1. Electron carriers transfer electrons to cytochromes in membrane 2. Cytochromes transfer electrons to O2 3. O2 transfers electrons to H2O ii. Flow of Protons 1. Energy released by electrons pumps protons (H+) from the intracellular matrix into the inner mitochondrial space 2. Protons are pumped through the ATP synthase from low to high concentration Electron Transport Chain 3. Protons are released from the ATP synthase in the form of ATP IV. Photosynthesis (2‐Step Process) a. Light Dependent Reaction (Light Reaction) i. Sunlight hits chlorophyll ii. Chlorophyll excites an electron 1. Path 1 a. Electron loses energy b. Electron energy pumps protons (H+) through the membrane c. Protons (H+) are pumped through the ATP synthase from low to high concentration d. Protons (H+) are released from the ATP synthase in the form of ATP 2. Path 2 a. Electrons passed to NADP+ b. NADP+ and electrons form NADPH iii. Photolysis 1. “Breaking water by light” 2. H2O H+ + e‐ + O2 3. Replaces electrons lost by reactions 4. Donates O2 to reactions b. Light In‐dependent Reaction (Dark Reaction; Calvin‐Benson Cycle) i. Uses energy in ATP + NADPH from Light Reaction to form “food” ii. CO2 (1 carbon molecule) + RuBP (5 carbon molecule) + RUBISCO Temporary (6 carbon molecule) 2 (3 carbon molecules) 1. Rubisco: Enzyme that catalyzes the reaction RuBP Carboxylase a. 2. Product a. PGAL (3 carbon molecule) PGALs form Glucose and other polysaccarides such b. as starch. V. Forms of Carbon a. In a hot environment, Rubisco does not function properly i. Grabs O2 instead of CO2 b. C3 Photosynthesis: i. Normal Way c. C4 Photosynthesis: i. Solves Rubisco problem in hot environments ii. Eliminates O2 Impermeable Membrane Light Reaction No CO2 or O2 O2 can cross CO2 3C 3C 4C 4C CO2 C4 Special Anatomy iii. Process 1. CO2 combines with 3C to form 4C 2. 4C travels over the impermeable membrane 3. 4C breaks into 3C and CO2 4. Rubisco only finds CO2 No O2 5. Rubisco catalyzses reaction with CO2 to form 6C 6. 6C breaks into 2 ‐ 3C 7. 3C travels back over membrane to attach to more O2 d. CAM Photosynthesis: i. Stomates are open during the night when it is cool 1. CO2 enters 2. CO2 4C for storage ii. Stomates are closed during the day when it is hot 1. No H2O loss 2. 4C slowly broken down into CO2 during the course of the day iii. CAM Plant has a normal leaf anatomy R ...
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