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7.1/7.2 Importance of Cellular Respiration & Glycolysis Cellular Respiration

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Text of 7.1/7.2 Importance of Cellular Respiration & Glycolysis Cellular Respiration

Cellular Respiration

7.1/7.2Importance of Cellular Respiration & GlycolysisCellular Respiration1Complementary ReactionsPhotosynthesis: series of reactions that convert light into chemical energy to produce energy-rich glucose molecules.Glucose can be used immediately or stored.Cellular Respiration: series of reactions that release the energy stored in glucose (in the form of ATP)CO2(g) + H2O(l) + energy C6H12O6(s) + O2(g)C6H12O6(s) + O2(g) CO2(g) + H2O(l) + energy2Compare and Contrast

3IntermediatesOxidation-reduction (redox) reactions produce intermediate products used by cells to complete processesLEO the lion goes GERPhotosynthesis: NADPH (reduced from of NADP+) and ATPCellular Respiration: NADH (reduced form of NAD+) and FADH2 (reduced form of FAD+)Serve as electron carriers: transfer electrons through redox reactionsEnergy released can be used to make ATP (attach ADP to Pi)4Cellular RespirationBreaking down of large energy molecules of glucose into smaller moleculesThe smaller you break them down, the more energy you can derive from the processThe energy released in cellular respiration is used to synthesize ATPGlucose molecules must be converted into another form of energy (ATP) before it is useful to the body

5ATPEstimated 1 billion molecules of ATP in a human cell- continuously broken down into ADP and Pi and reformedMost processes that require ATP energy can be placed into one of the following categories (Table 1 pg 206)- motion- transport of ions/molecules- building of molecules- switching reactions on and off- bioluminescence

6Glucose Our blood sugar: high energy content, small, highly soluble- ideal for transportationChemical bonds of reactant food molecules (glucose) broken during respirationBreak bonds = requires energyNew bonds = energy releasedRespiration an energy-releasing process: more energy released during formation of product moleculesSingle glucose molecule- 36% converted into energy of ATP- 64% released as heat7Types of Cellular RespirationAerobic cellular respiration: requires O2 and involves complete oxidation of glucose (produces 36 ATP)- Stage 1: glycolysis (cytoplasm)- Stage 2: pyruvate oxidation (mitochondria)- Stage 3: Krebs Cycle (mitochondria)- Stage 4: ETC and chemiosmosis (inner mitochondria)Anaerobic cellular respiration: occurs in absence of O2 and glucose is not completely oxidized.- Stage 1: glycolysis (cytoplasm)- Stage 2: fermentation (cytoplasm)2 types of anaerobic respiration: one produces ethanol, one produces lactic acidNOTE: BOTH BEGIN WITH GLYCOLYSIS!!!


9Aerobic cellular respiration: Overview

10Stage 1: Glycolysissugar splittingNo oxygen requiredThus it is the first step for both aerobic and anaerobic respirationOccurs in the cytoplasmStarts with glucose (6-carbon sugar)2 ATP molecules are used in the first stages of glycolysis (investment phase)2 NAD+ removes H+ ions and forms 2 NADHLater enough energy is released to form 4 ATP, which will be available to be used in cellular functionsGlycolysis produces TWO 3-carbon pyruvate moleculesNet production of 2 ATP11Glycolysis

12GlycolysisRelatively inefficientOnly transfers about 2.2% of free energy available in glucose to ATPSome released as heat, but remainder tied up in pyruvate and 2 NADH moleculesglycolysis

13Glycolysis Review:Reactants:1 Glucose4 ADP4 Pi2 ATP2 NAD+2 H+

Products:2 Pyruvate4 ATP (therefore, net gain of 2 ATP)2 ADP2 NADH14