* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download oxidation
Lactate dehydrogenase wikipedia , lookup
Butyric acid wikipedia , lookup
Biosynthesis wikipedia , lookup
Fatty acid synthesis wikipedia , lookup
Metalloprotein wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Mitochondrion wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Photosynthesis wikipedia , lookup
NADH:ubiquinone oxidoreductase (H+-translocating) wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Electron transport chain wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Nicotinamide adenine dinucleotide wikipedia , lookup
Microbial metabolism wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
Biochemistry wikipedia , lookup
Introduction In eukaryotes, cellular respiration – harvests energy from food, – yields large amounts of ATP, and – Uses ATP to drive cellular work. A similar process takes place in many prokaryotic organisms. © 2012 Pearson Education, Inc. Figure 6.0_1 Chapter 6: Big Ideas Cellular Respiration: Aerobic Harvesting of Energy Fermentation: Anaerobic Harvesting of Energy Stages of Cellular Respiration Connections Between Metabolic Pathways 6.1 Photosynthesis and cellular respiration provide energy for life Life requires energy. In almost all ecosystems, energy ultimately comes from the sun. In photosynthesis, – some of the energy in sunlight is captured by chloroplasts, – atoms of carbon dioxide and water are rearranged, and – glucose and oxygen are produced. © 2012 Pearson Education, Inc. Figure 6.1 Sunlight energy ECOSYSTEM Photosynthesis in chloroplasts CO2 Glucose H2O O2 Cellular respiration in mitochondria (for cellular work) ATP Heat energy Figure 6.2 O2 Breathing CO2 Lungs CO2 Bloodstream O2 Muscle cells carrying out Cellular Respiration Glucose O2 CO2 H2O ATP Figure 6.3 C6H12O6 6 Glucose Oxygen O2 6 CO2 Carbon dioxide 6 H2O ATP Water Heat 6.5 Cells tap energy from electrons “falling” from organic fuels to oxygen Energy can be released from glucose by simply burning it. The energy is dissipated as heat and light and is not available to living organisms. © 2012 Pearson Education, Inc. 6.5 Cells tap energy from electrons “falling” from organic fuels to oxygen The movement of electrons from one molecule to another is an oxidation-reduction reaction, or redox reaction. In a redox reaction, – the loss of electrons from one substance is called oxidation, – the addition of electrons to another substance is called reduction, – a molecule is oxidized when it loses one or more electrons, and – reduced when it gains one or more electrons. © 2012 Pearson Education, Inc. Figure 6.5A Loss of hydrogen atoms (becomes oxidized) C6H12O6 6 O2 6 CO2 6 H2O Glucose Gain of hydrogen atoms (becomes reduced) ATP Heat Figure 6.5C NADH NAD ATP 2 Controlled release of energy for synthesis of ATP H 2 1 O 2 2 2 H H 2O 6.6 Overview: Cellular respiration occurs in three main stages Cellular respiration consists of a sequence of steps that can be divided into three stages. – Stage 1 – Glycolysis – Stage 2 – Pyruvate oxidation and citric acid cycle – Stage 3 – Oxidative phosphorylation © 2012 Pearson Education, Inc. 6.6 Overview: Cellular respiration occurs in three main stages Stage 1: Glycolysis – occurs in the cytoplasm, – begins cellular respiration, and – breaks down glucose into two molecules of a threecarbon compound called pyruvate. © 2012 Pearson Education, Inc. 6.6 Overview: Cellular respiration occurs in three main stages Stage 2: The citric acid cycle – takes place in mitochondria, – oxidizes pyruvate to a two-carbon compound, and – supplies the third stage with electrons. © 2012 Pearson Education, Inc. 6.6 Overview: Cellular respiration occurs in three main stages Stage 3: Oxidative phosphorylation – involves electrons carried by NADH and FADH2, – shuttles these electrons to the electron transport chain embedded in the inner mitochondrial membrane, – involves chemiosmosis, and – generates ATP through oxidative phosphorylation associated with chemiosmosis. © 2012 Pearson Education, Inc. Figure 6.6_1 CYTOPLASM NADH Electrons carried by NADH NADH Glycolysis Pyruvate Glucose Pyruvate Oxidation Citric Acid Cycle FADH2 Oxidative Phosphorylation (electron transport and chemiosmosis) Mitochondrion ATP ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation Figure 6.7Ca_s1 Steps 1 – 3 A fuel molecule is energized, using ATP. Glucose ATP Step ENERGY INVESTMENT PHASE 1 ADP P Glucose 6-phosphate P Fructose 6-phosphate P Fructose 1,6-bisphosphate 2 ATP 3 ADP P Figure 6.7Ca_s2 Steps 1 – 3 A fuel molecule is energized, using ATP. Glucose ATP Step ENERGY INVESTMENT PHASE 1 ADP P Glucose 6-phosphate P Fructose 6-phosphate P Fructose 1,6-bisphosphate 2 ATP 3 ADP Step 4 A six-carbon intermediate splits into two three-carbon intermediates. P 4 P P Glyceraldehyde 3-phosphate (G3P) Figure 6.7Cb_s1 Step 5 A redox reaction generates NADH. NAD NAD 5 P NADH ENERGY PAYOFF PHASE P P H 5 P NADH H P P P P 1,3-Bisphosphoglycerate Figure 6.7Cb_s2 Step 5 A redox reaction generates NADH. NAD NAD 5 P NADH 5 P NADH H H P P P ADP Steps 6 – 9 ATP and pyruvate are produced. ENERGY PAYOFF PHASE P P P 1,3-Bisphosphoglycerate P 3-Phosphoglycerate ADP 6 6 ATP ATP P 7 7 P P 2-Phosphoglycerate 8 H2O P P ADP Phosphoenolpyruvate (PEP) ADP 9 9 ATP 8 H2O ATP Pyruvate Figure 6.8 NAD NADH H 2 CoA Pyruvate Acetyl coenzyme A 1 CO2 3 Coenzyme A Figure 6.9A Acetyl CoA CoA CoA 2 CO2 Citric Acid Cycle 3 NAD FADH2 3 NADH FAD 3 H ATP ADP P Figure 6.9B_s3 Acetyl CoA CoA CoA 2 carbons enter cycle Oxaloacetate 1 Citrate NADH H NAD 5 NAD NADH 2 H Citric Acid Cycle CO2 leaves cycle Malate FADH2 Alpha-ketoglutarate 4 3 FAD CO2 leaves cycle NAD Succinate ADP Step 1 Acetyl CoA stokes the furnace. P Steps 2 – 3 ATP NADH, ATP, and CO2 are generated during redox reactions. NADH H Steps 4 – 5 Further redox reactions generate FADH2 and more NADH. Figure 6.10_1 H H H H H Mobile electron carriers Protein complex of electron carriers H H H III H ATP synthase IV I II FADH2 Electron flow NADH NAD FAD 2 H 1 O 2 2 H2O H ADP P ATP H Electron Transport Chain Oxidative Phosphorylation Chemiosmosis 6.12 Review: Each molecule of glucose yields many molecules of ATP Recall that the energy payoff of cellular respiration involves 1. glycolysis, 2. alteration of pyruvate, 3. the citric acid cycle, and 4. oxidative phosphorylation. © 2012 Pearson Education, Inc. Figure 6.12 CYTOPLASM Electron shuttles across membrane 2 NADH Mitochondrion 2 NADH or 2 FADH2 6 NADH 2 NADH Glycolysis 2 Pyruvate Glucose Pyruvate Oxidation 2 Acetyl CoA Citric Acid Cycle 2 FADH2 Oxidative Phosphorylation (electron transport and chemiosmosis) Maximum per glucose: 2 ATP by substrate-level phosphorylation 2 ATP by substrate-level phosphorylation about 28 ATP by oxidative phosphorylation About 32 ATP Animation: Fermentation Overview Right click on animation / Click play © 2012 Pearson Education, Inc. Figure 6.13A 2 ADP 2 P 2 ATP Glycolysis Glucose 2 NAD 2 NADH 2 Pyruvate 2 NADH 2 NAD 2 Lactate Figure 6.13B Glucose 2 NAD Glycolysis 2 ADP 2 P 2 ATP 2 NADH 2 Pyruvate 2 NADH 2 CO2 2 NAD 2 Ethanol 6.14 EVOLUTION CONNECTION: Glycolysis evolved early in the history of life on Earth The ancient history of glycolysis is supported by its – occurrence in all the domains of life and – location within the cell, using pathways that do not involve any membrane-bounded organelles. © 2012 Pearson Education, Inc. CONNECTIONS BETWEEN METABOLIC PATHWAYS © 2012 Pearson Education, Inc. 6.15 Cells use many kinds of organic molecules as fuel for cellular respiration Although glucose is considered to be the primary source of sugar for respiration and fermentation, ATP is generated using – carbohydrates, – fats, and – proteins. © 2012 Pearson Education, Inc. Figure 6.15 Food, such as peanuts Carbohydrates Sugars Fats Proteins Glycerol Fatty acids Amino acids Amino groups Glucose G3P Pyruvate Glycolysis Pyruvate Oxidation Acetyl CoA ATP Citric Acid Cycle Oxidative Phosphorylation Figure 6.16 ATP needed to drive biosynthesis Citric Acid Cycle ATP Pyruvate Oxidation Acetyl CoA Glucose Synthesis Pyruvate G3P Glucose Amino groups Amino acids Proteins Fatty acids Glycerol Fats Cells, tissues, organisms Sugars Carbohydrates You should now be able to 1. Compare the processes and locations of cellular respiration and photosynthesis. 2. Explain how breathing and cellular respiration are related. 3. Provide the overall chemical equation for cellular respiration. 4. Explain how the human body uses its daily supply of ATP. © 2012 Pearson Education, Inc. You should now be able to 5. Explain how the energy in a glucose molecule is released during cellular respiration. 6. Explain how redox reactions are used in cellular respiration. 7. Describe the general roles of dehydrogenase, NADH, and the electron transport chain in cellular respiration. 8. Compare the reactants, products, and energy yield of the three stages of cellular respiration. © 2012 Pearson Education, Inc. You should now be able to 9. Explain how rotenone, cyanide, carbon monoxide, oligomycin, and uncouplers interrupt critical events in cellular respiration. 10. Compare the reactants, products, and energy yield of alcohol and lactic acid fermentation. 11. Distinguish between strict anaerobes and facultative anaerobes. 12. Explain how carbohydrates, fats, and proteins are used as fuel for cellular respiration. © 2012 Pearson Education, Inc. Figure 6.UN01 CYTOPLASM Mitochondrion NADH Electrons carried by NADH Glycolysis Glucose Pyruvate Pyruvate Oxidation Substratelevel ATP phosphorylation NADH FADH2 Citric Acid Cycle Oxidative Phosphorylation (electron transport and chemiosmosis) SubstrateATP level ATP phosphorylation Oxidative phosphorylation Figure 6.UN02 Cellular respiration has three stages generates oxidizes uses produce some produces many energy for glucose and organic fuels (a) (b) (d) to pull electrons down (c) cellular work (f) by a process called chemiosmosis uses (g) H diffuse through ATP synthase (e) uses pumps H to create H gradient to