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Cellular Respiration Slide 2 All living things need energy Energy in the form of Food =chemical energy Cell energy= ATP Slide 3 How Do We Get Energy From ATP? By breaking the high- energy bonds between the last two phosphates in ATP By breaking the high- energy bonds between the last two phosphates in ATP Copyright Cmassengale Slide 4 When is ATP Made in the Body? During a Process called Cellular Respiration that takes place in both Plants & Animals During a Process called Cellular Respiration that takes place in both Plants & Animals Copyright Cmassengale Slide 5 What is cellular respiration ? Cellular respiration is the set of the metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into (ATP), metaboliccellsorganisms biochemical energynutrients The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy catabolic reactions Slide 6 Cellular Respiration Includes pathways that require oxygen Includes pathways that require oxygen Breakdown of one glucose molecule produces 38 ATP molecules Breakdown of one glucose molecule produces 38 ATP molecules Copyright Cmassengale Slide 7 Overall Equation for Cellular Respiration 6CO 2 + 6H 2 0 + 38 ATPs C 6 H 12 O 6 + 6O 2 YIELDS Slide 8 Important Molecules in Cellular Respiration CO 2 Carbon Dioxide ATP Adenine triphosphate NAD Nicotinamide adenine dinucleotide FAD Flavin adenine dinucleotide Slide 9 What are the Stages of Cellular Respiration? STEP 1 - Glycolysis STEP 1 - Glycolysis STEP 2 - The Krebs Cycle STEP 2 - The Krebs Cycle STEP 3 - The Electron Transport Chain (ETC) STEP 3 - The Electron Transport Chain (ETC) Slide 10 Where Does Cellular Respiration Take Place? It actually takes place in two parts of the cell: It actually takes place in two parts of the cell: Glycolysis occurs in the Cytoplasm Krebs Cycle & ETC Takeplace in the Mitochondria Krebs Cycle & ETC Take place in the Mitochondria Slide 11 Copyright Cmassengale Slide 12 STEP 1 Glycolysis Glycolysis is takes place in the cytosol of cells in all living organisms.cytosol This pathway can function with or without the presence of oxygen. process converts one molecule of glucose into two molecules of pyruvate (pyruvic acid), glucosepyruvate Slide 13 generating two net molecules of ATP.ATP Four molecules of ATP per glucose are actually produced, however, two are consumed as part of the preparatory phase.preparatory phase The overall reaction can be expressed this way: Glucose + 2 NAD + + 2 P i + 2 ADP 2 pyruvate + 2 NADH + 2 ATP + 2 H + + 2 H 2 O + heatpyruvate Slide 14 Slide 15 Copyright Cmassengale Slide 16 Glycolysis Summary Produces 2 NAD and 4 ATP molecules Produces 2 NAD and 4 ATP molecules (2 ATP Used & 4 Produced so overall 2 ATP molecules from glycolysis) (2 ATP Used & 4 Produced so overall 2 ATP molecules from glycolysis) 2 molecule of Pyruvate 2 molecule of Pyruvate Slide 17 Slide 18 Steps 2: The Fate of PYRUVATE 1. As pyruvate enters the mitochondrion, a modifies pyruvate to acetyl CoA which enters the Krebs cycle in the matrix. 2. A carboxyl group is removed as CO2. 3. A pair of electrons is transferred from the to NAD+ to form NADH Slide 19 2 molecule of pyruvate produce 2 NADH Slide 20 When oxygen is present, the mitochondria will undergo aerobic respiration which leads to the Krebs cycle. However, if oxygen is not present, fermentation of the pyruvate molecule will occur. In the presence of oxygen, when acetyl-CoA is produced, the molecule then enters the citric acid cycle (Krebs cycle) acetyl-CoAcitric acid cycle Slide 21 inside the mitochondrial matrix, and gets oxidized to CO 2CO 2 while at the same time reducing NAD to NADH.NADNADH NADH can be used by the electron transport chain to create further ATP as part of oxidative phosphorylation.NADHelectron transport chain ATP The citric acid cycle is an 8-step process involving different enzymes and co-enzymes. Slide 22 Steps3: KREBS CYCLE or TCA This is also called the citric acid or the tricarboxylic acid cycle Takes place in matrix of mitochondria Takes place in matrix of mitochondria Requires Oxygen (Aerobic) Requires Oxygen (Aerobic) Each cycle produces 1 ATP, 3 NADH, and 1 FADH Slide 23 The TCA or KREBS CYCLE 4 CO2 6NADH 2FADH 2 more ATP Slide 24 NETS: 3NADH, 1ATP, 1FADH 2, & 2CO 2 Slide 25 The conversion of pyruvate and the Krebs cycle produces large quantities of electron carriers. So what do you think the major purpose of the Krebs cycle is?? Slide 26 Electron Transport The mitochondria has two membranes the outer one and the inner membrane The H+ which are brought to mitochondria accumulate between these two membranes. Slide 27 the electrons move from molecule to molecule until they combine with oxygen and hydrogen ions to form water. As they are passed along the chain, the energy carried by these electrons is stored in the mitochondrion in a form that can be used to synthesize ATP Slide 28 1. Electrons carried by NADH are transferred to the first molecule in the electron transport chain 2. The electrons continue along the chain that includes several cytochrome proteins and one lipid carrier. 3. The electrons carried by FADH2 added to a later point in the chain. 4. Electrons from NADH or FADH2 ultimately pass to oxygen. 5. The electron transport chain generates no ATP directly. Slide 29 Slide 30 Copyright Cmassengale Slide 31 ONE GLUCOSE MOLECULE PRODUCES 38 ATP Each NADH 3 ATP Each FADH 2 ATP Glycolysis (2 NADH)6 ATP Prep for Citric Acid6 ATP Citric Acid (6 NADH) 18 ATP (2 FADH 2 )4 ATP 34 ATP direct4 ATP total 38 ATP Slide 32 If no oxygen is available, cells can obtain energy through the process of anaerobic respiration. A common anaerobic process is fermentation. Fermentation is not an efficient process and results in the formation of far fewer ATP molecules than aerobic respiration. There are two primary fermentation processes: 1.Lactic Acid Fermentation 2.Alcohol Fermentation What happens when there is no oxygen to accept the electrons? to accept the electrons? Slide 33 Fermentation allows the production of a small amount of ATP without oxygen. Slide 34 Lactic acid fermentation occurs when oxygen is not available. For example, in muscle tissues during rapid and hard exercise, muscle cells may be depleted of oxygen. They then switch from respiration to fermentation. Slide 35 The pyruvic acid formed during glycolysis is broken down to lactic acid and energy is released (which is used to form ATP). Glucose Pyruvic acid Lactic acid + energy Slide 36 Lactic acid that builds up in the tissue causes a burning, painful sensation. results in muscle soreness Slide 37 Copyright Cmassengale Slide 38 occurs in yeasts and some bacteria. Alcohol fermentation Slide 39 Alcohol Fermentation Pyruvate is converted to ethanol (ethyl alcohol) in 2 steps. 1. carbon dioxide is released from pyruvate, which is converted to acetaldehyde. 2. acetaldehyde is reduced by NADH to ethanol. Regenerating a supply of NAD + Slide 40 Slide 41 Anaerobic RespirationAerobic Respiration Anaerobic respiration is respiration without oxygen; the process uses a respiratory electron transport chain but does not use oxygen as the electron acceptors Aerobic respiration uses oxygen Definition Produces lactic acid (in lactic acid fermentation but not in alcoholic fermentation) Does not produce lactic acidProduction of lactic acid: Low (2 ATP molecules) High (36-38 ATP molecules) Amount of energy released: Lactic Acid Fermentation - lactic acid, ATP Alcoholic Fermentation - ethyl alcohol, ATP, carbon dioxide Carbon dioxide, water, ATPProducts: glucoseglucose, oxygenReactants: Slide 42 AnaerobicAerobic CytoplasmCytoplasm and mitochondriaSite of reactions: Glycolysis, fermentationGlycolysis, Krebs cycle, Electron Transport Chain Stages: Copyright Cmassengale Slide 43 The aerobic system requires 60 to 80 seconds to produce energy for resynthesizing ATP from ADP + P. The heart rate and respiratory rate must increase sufficiently to transport the required amount of O2 to the muscle cells, allowing glycogen to break down in the presence of oxygen. Copyright Cmassengale Slide 44 the lactic acid system need 8 to 10 seconds to produce energy Copyright Cmassengale Slide 45 Slide 46 Summary Quiz What are the reactants of aerobic respiration?? Products? Equation? List the three respiratory stages: Where in the cell do each occur? What are the products of each? How much ATP is produced by Anaerobic gylcolysis? Aerobic glycolysis? List the 2 types of fermentation??