Cellular Respiration. Cellular respiration – process in which mitochondria break down food molecules to produce ATP in plants & animals; occurs in the

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<ul><li><p>Cellular Respiration</p></li><li><p>Cellular respiration process in which mitochondria break down food molecules to produce ATP in plants &amp; animals; occurs in the presence of oxygen</p><p>Nutrients + oxygen water+ ATP+ CO2</p><p>The equation for cellular respiration is:6O2 + C6H12O6 6CO2 + 6H2O + Energyoxygen + glucose carbon dioxide + water + energy</p><p>Process changes organic chemical energy (glucose) into inorganic chemical energy ATP</p></li><li><p>Overview of Cellular Respiration3 Stages:Glycolysis anaerobic process; does not require oxygen - cytoplasmCitric Acid (Krebs) Cycle aerobic; does require oxygen mitochondriaElectron Transport Chain aerobic; does require oxygen - mitochondria</p></li><li><p>GlycolysisGlycolysis breaks down glucose into two molecules of pyruvic acid (colorless acid)This reaction uses enzymes and takes place in the cytoplasm of the cell (anaerobic reaction)Produces:2 Pyruvic acid molecules (used in Step 2 of cellular respiration)2 ATP molecules (energy cell can use)2 NADH molecules (electron carrier)</p></li><li><p>2 ATP2 ADP4 ADP4 ATP2 PyruvicacidAt the beginning of glycolysis, the cell uses up 2 molecules of ATP to start the reaction.</p><p>2 ATP 2NAD+2To the electron transport chain</p></li><li><p>FermentationFermentation releases energy from food molecules by producing ATP in the absence of oxygen; anaerobic process</p><p>During fermentation, cells convert NADH to NAD+ by passing high-energy electrons back to pyruvic acid.This action converts NADH back into NAD+, and allows glycolysis to continue producing a steady supply of ATP. </p></li><li><p>2 Types of Fermentation</p><p>1. Lactic acid fermentation process that supplies energy when O2 is scarceEx.) released during vigorous exercise; feel the burn</p><p>2. Alcoholic fermentation used to produce CO2 and ethyl alcoholEx.) Yeast Cells</p></li><li><p>The Krebs CycleNamed after Hans Krebs British biochemist; won Nobel Prize in 1953 for discovery of this cycleAerobic processPyruvic acid produced from glycolysis along w/O2 start the 2nd stage of cellular respirationPyruvic acid is broken down into CO2 in a series of endergonic reactions</p></li><li><p>2 Parts of the Krebs CyclePart A Step 1: Cycle begins when pyruvic acid enters the mitochondrion</p></li><li><p>The Krebs Cycle</p><p>2. Carbon molecule is removed, forming CO2, &amp; electrons are removed, changing NAD+ to NADH.</p><p>3. Coenzyme A joins the 2-carbon molecule, forming acetyl-CoA.</p></li><li><p>The Krebs Cycle Citric acid4. Acetyl-CoA then adds the 2-carbon acetyl group to a 4-carbon compound, forming citric acid.</p></li><li><p>The Krebs Cycle</p><p>Part BStep 1: Citric acid is broken down into a 5-carbon compound, then into a 4-carbon compound.</p></li><li><p>The Krebs Cycle Step 2: Two more molecules of CO2 are released and electrons join NAD+ and FAD, forming NADH and FADH2.</p></li><li><p>The Krebs Cycle Result: 1 molecule of ATP is produced</p></li><li><p>Energy totals from 1 molecule of pyruvic acid is :4 NADH1 FADH21 ATP</p><p>Electron Transport Chain = 3rd step in cellular respiration, aerobic process, uses the high-energy electron carriers from the Krebs Cycle to convert ADP into ATP.</p><p>Carrier molecules produced are used to generate ATP via the Electron Transport Chain</p></li><li><p>Electron Transport ChainHigh-energy electrons from NADH and FADH2 are passed along the electron transport chain from one carrier protein to the next.</p></li><li><p>The TotalsGlycolysis produces just 2 ATP molecules per molecule of glucose.The complete breakdown of glucose through cellular respiration, including glycolysis, results in the production of 36 molecules of ATP.</p></li><li><p>The Totals: Overview</p></li><li><p>Comparing Photosynthesis and Cellular Respiration Comparing Photosynthesis and Cellular RespirationThe energy flows in photosynthesis and cellular respiration take place in opposite directions.</p></li><li><p>On a global level, photosynthesis and cellular respiration are also opposites. </p><p>Photosynthesis removes carbon dioxide from the atmosphere and cellular respiration puts it back.Photosynthesis releases oxygen into the atmosphere and cellular respiration uses that oxygen to release energy from food.</p><p>******</p></li></ul>