Page 155 159 read multiple times Page 161 bottom paragraph first column Basics Living things obtain energy from food Photosynthesis provides the food in the form of glucose Cellular Respiration breaks down glucose to release ATP energy to drive cell processes ATP is adenosine triphosphates The phosphate bonds release much energy when broken to release phosphate ATP is continuously used and cells require more food to produce more ATP ATP H2O ADP P energy released glucose P ADP ATP Oxidation Reduction Reactions Redox Reaction These reactions release a lot of ATP energy Involve the transfer of one or more electrons from electron donors or electron acceptors The molecule that loses electrons is oxidized The molecule that gains electrons is reduced oil rig oxygen is often an electron acceptor H2O Substances can be oxidized if they lose a hydrogen atom which contains an electron In cellular respiration oxygen accepts hydrogen atoms to become water Chemiosmotic ATP Synthesis Making ATP using chemicals H atoms passing through a membrane usually in the mitochondria The Hydrogens come from food glucose Aerobic with oxygen reactions produce more ATP Anaerobic without oxygen reactions produce less ATP Types of Energy Reactions 1 Glycolysis Occurs in the cytoplasm Either aerobic or anaerobic Breaks down the 6 carbon sugar glucose C6H12O6 to two 3 carbon pyruvate molecules Produces two ATP molecules and hydrogen atoms Picked up by the electron acceptor NAD nicotinamide adenine dinucleotide to form NADH which can give away the H later on Ancient reaction Humans use it when oxygen is depleted after running Pyruvates are used during cellular respiration when oxygen is present Products NADH and pyruvic acid used in other energy reactions Page 155 159 read multiple times Page 161 bottom paragraph first column 2 Fermentation Reactions Anaerobic Uses products from glucose to produce carbon dioxide alcohol or lactic acid NADH is oxidized loses H to become NAD which travels back to the glycolysis pathway to generate more ATP a Alcohol Fermentation Anaerobic Occurs in yeast cells Products include alcohol and two ATP molecules Yeast cells break down glucose to form pyruvates The pyruvates molecules lose carbon atoms to form acetaldehyde The acetaldehyde accepts two hydrogen from NADH to form ethanol alcohol NAD then returns to glycolysis pathways to generate more ATP b Lactic Acid Fermentation Anaerobic Occurs in muscle cells during heavy exercise when oxygen is very low Without adequate oxygen the muscle cells ferment to gain a little ATP As muscle cells ferment due to lack of oxygen pyruvates from glycolysis are reduced as they accept hydrogens from NADH to form NAD which is reused in glycolysis The lactic acid formed is a waste product that causes cramps in the muscles Once the person animal rests and oxygen increases in the cells the lactic acid is converted to glycogen in the liver and the muscles recover Only two ATPS are produced 3 Cellular Respiration Aerobic In the mitochondria Products of glycolysis are used 38 ATP produced from each glucose molecule The carbons from glucose are released as CO2 The hydrogen are picked up by NAD and FAD to be sent to the electron transport chain to produce the majority of ATP 34 Begins with glycolysis which produces pyruvates and NADH Kreb s Cycle the pyruvates give up carbon as CO2 to form acetyl groups mre NADH is formed More H atoms are released to be picked up by NAD and FAD Only one ATP is formed each cycle The main goal is to generate the H atoms to form NADH and FADH Electron Transport Chain the majority of ATP is produced here within the membranes of the mitochondria NADH and FADH pass their hydrogens to carrier molecules that create a hydrogen gradient As the hydrogens pass down the gradient ATP is formed from ADP and P called phosphorylation NAD and Page 155 159 read multiple times Page 161 bottom paragraph first column FAD can reenter the Kreb s Cycle to pick up more hydrogens Oxygen is the final electron acceptor forming water
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