Bio101 dioxide CHAPTER 6 Study Guide Questions 1 Breathing supplies oxygen for use in cellular respiration and removes carbon 2 During the cellular respiration electrons are transferred from glucose to oxygen releasing energy Oxygen attracts electrons very strongly and an electron loses potential energy when it is transferred to oxygen An important player in the process of oxidizing glucose is a coenzyme called NAD which accepts electrons and becomes reduced to NADH In a redox reaction the loss of electrons from one substance is called oxidation and the addition of electrons to another substance is called reduction 3 Stage 1 Glycolysis occurs in the cytosol of the cell Glycolysis begins cellular respiration by breaking glucose into two molecules of three carbon compound called pyruvate Stage 2 Pyruvate oxidation and the citric acid cycle take place within the mitochondria Pyruvate is oxidized to a two carbon compound The citric acid cycle then completes the breakdown of glucose to carbon dioxide Thus the CO2 that you exhale is formed in the mitochondria of your cells during this second stage of respiration Stage 3 Oxidative phosphorylation involves electron transport and a process known as chemiosmosis NADH and a related electron carrier FADH2 shuttle electrons to an electron transport chain embedded in the inner mitochondrial membrane Most of the ATP produced by cellular respiration is generated by oxidative phosphorylation which uses the energy released by the downhill fall of electrons from NADH and FADH2 to oxygen to phosphorylate ADP Stage 3 is the only one that uses oxygen an produces the most energy in cellular respiration 4 Two molecules of pyruvate two molecules of ATP and two molecules od NADH Substrate level phosphorylation transfer of a phosphate group from a substrate to ADP producing ATP 5 The oxidation of glucose to pyruvate during glycolysis releases energy which is stored in ATP and in NADH The cell can use the energy in ATP immediately but for it to use the energy in NADH must pass down an electron transport chain located in the inner mitochondrial membrane And the pyruvate molecules still hold most of the energy of glucose these molecules still hold most of the energy of glucose these molecules will be oxidized in the citric acid cycle 6 The electron transport chain is located in the inner membrane of the mitochondria Energy released is used again In chemiosmosis the potential energy of this concentration gradient is used to make ATP Bio101 oxygen The final electron acceptor in the electron transport chain is oxygen In the end the electrons join with positive hydrogen molecules and oxygen to form water 7 Fermentation is a way of harvesting chemical energy that does not require Alcohol fermentation is the anaerobic pathway carried out by yeasts in which simple sugars are converted to ethanol and carbon dioxide Lactic acid fermentation is a process by which glucose and other six carbon sugars are converted into cellular energy and the metabolite lactate