Chapter 9 Notes Cellular Respiration 9-1 Chemical Pathways All living organisms need food to survive. Food provides living things with the chemical building blocks they need to grow and reproduce. 9-1 Chemical Pathways 1 gram of glucose releases 3811 calories of heat energy Calorie (c): the amount of energy needed to raise the temperature of 1 gram of water 1 Celsius degree The calories on food labels (C) are kilocalories or 1000 calories 9-1 Chemical Pathways Cells gradually release energy from glucose and other food compounds. Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. - 3 parts: glycolysis, the Krebs cycle, and the electron transport chain Electrons carried in NADH Pyruvic acid Glucose Glycolysis Krebs Cycle Electrons carried in NADH and FADH2 Cytoplasm Mitochondrion Electron Transport Chain 9-1 Chemical Pathways Equation for Cellular Respiration 6O2 + C6H12O6 6CO2 + 6 H2O + Energy oxygen+glucose carbon+water+energy dioxide 9-1 Chemical Pathways Glucose Glycolysis Krebs cycle Fermentation (without oxygen) Electron transport Alcohol or lactic acid 9-1 Chemical Pathways The first set of chemical reactions in cellular respiration is glycolysis. Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3-carbon compound 9-1 Chemical Pathways Net results of glycolysis - 2 molecules of ATP are gained - 2 molecules of NADH are gained - 2 molecules of pyruvic acid (3C) are formed from 1 glucose molecule 9-1 Chemical Pathways 2 ATP 2 ADP 4 ADP 4 ATP Glucose 2 Pyruvic acid 9-1 Chemical Pathways When oxygen is present in the cell, glycolysis is followed by the Krebs cycle. If there is no oxygen present, glycolysis is followed by fermentation. Fermentation releases energy from food molecules in the absence of oxygen 9-1 Chemical Pathways Because fermentation does not require oxygen it is said to be anaerobic. The two main types of fermentation are alcoholic fermentation and lactic acid fermentation 9-1 Chemical Pathways 9-1 Chemical Pathways 9-1 Chemical Pathways Alcoholic fermentation is used mainly by plants and yeasts - alcohol is the product Lactic acid fermentation occurs in muscle cells when the body cannot supply enough oxygen to the tissues - lactic acid is the product Section Quiz The raw materials required for cellular respiration are carbon dioxide and oxygen. glucose and water. glucose and oxygen. carbon dioxide and water. Section Quiz Glycolysis occurs in the mitochondria. cytoplasm. nucleus. chloroplasts. Section Quiz The net gain of ATP molecules after glycolysis is 3 2 3 4 ATP molecules. ATP molecules. pyruvic acid molecules. pyruvic acid molecules Section Quiz Fermentation releases energy from food molecules in the absence of oxygen. glucose. NADH. alcohol. Section Quiz The first step in fermentation is always lactic acid production. the Krebs cycle. glycolysis. alcohol production. 9-2 The Krebs Cycle and Electron Transport Oxygen is used for the final steps of cellular respiration. Because the pathway requires oxygen, it is said to be aerobic. In the presence of O2, pyruvic acid passes on to the second stage of cellular respiration, the Krebs cycle 9-2 The Krebs Cycle and Electron Transport During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions Net result of the Krebs cycle - 2 molecules of pyruvic acid enter - 8 molecules of NADH are gained - 2 molecules of FADH2 are gained - 2 molecules of ATP are gained Mitochondrion Citric Acid Production 9-2 The Krebs Cycle and Electron Transport From glycolysis and the Krebs cycle high energy electron carriers, NADH and FADH2, are produced. The electrons are then passed to the electron transport chain. The electron transport chain uses high energy electrons to convert ADP to ATP. ETC Movie pt 1 ETC Movie pt 2 9-2 The Krebs Cycle and Electron Transport 9-2 The Krebs Cycle and Electron Transport 9-2 The Krebs Cycle and Electron Transport 9-2 The Krebs Cycle and Electron Transport ATP synthase 9-2 The Krebs Cycle and Electron Transport Channel ATP synthase ATP 9-2 The Krebs Cycle and Electron Transport Each NADH make 3 ATP while each FADH2 makes 2 ATP 1 glucose molecule can then make 38 total ATP ( 4 ATP, 10 NADH 30 ATP, 2 FADH2 4 ATP) Cellular Respiration Animation Section Quiz The Krebs cycle breaks pyruvic acid down into oxygen. NADH. carbon dioxide. alcohol. Section Quiz In eukaryotes, the electron transport chain is located in the cell membrane. inner mitochondrial membrane. cytoplasm. outer mitochondrial membrane. Section Quiz To generate energy over long periods, the body must use stored ATP. lactic acid fermentation. cellular respiration. glycolysis. Section Quiz Which statement correctly describes photosynthesis and cellular respiration? Photosynthesis releases energy, while cellular respiration stores energy. Photosynthesis and cellular respiration use the same raw materials. Cellular respiration releases energy, while photosynthesis stores energy. Cellular respiration and photosynthesis produce the same products.