BIO BOOK NOTES CHAPTER 8 How Cells Make ATP Energy Releasing Pathways 1 2 3 4 8 1 Redox Reactions piration requiring molecular oxygen O2 most eukaryotes and prokaryotes carry out aerobic respiration a form of cellular res during nutrients are catabolized to carbon dioxide and water most cells use aerobic resp to obtain energy from glucose aerobic respiration of glucose is a redox reaction in which glucose becomes oxi dized and oxygen becomes reduced during this process the free energy of electrons is coupled to ATP synthesis 8 2 The Four Stages of Aerobic Respiration Glycolysis series of reactions in which glucose is degraded to pyruvate net profit of 2 ATP s hydro gen atoms are transferred to carriers can proceed anaerobically first phase involves investment of ATP second phase energy capture phase yields NADH and ATP Formation of Acetyl CoA pyruvate s degraded and combined with coenzyme A to form acetyl CoA hydrogen atoms are transferred to carriers CO2 is released pyruvate undergoes a process called oxidate decarboxylation Citric Acid Cycle Series of reactions in which the acetyl portion of acetyl CoA is degraded to CO2 hydro gen atoms are transferred to carriers ATP is synthesized also known as the tricarboxylic acid cycle and the Krebs cycle Electron Transport and Chemiosmosis chain of several electron transport molecules electrons are passed along chain released energy is used to form a proton gradient ATP is synthesized as protons diffuse down the gradi ent oxygen is final electron acceptor most reactions involved in aerobic respiration are one of three types Dehydrogenations reactions in which two hydrogen atoms are removed from the substrate and transferred to NAD or FAD Decarboxylations are reactions in which part of a carboxyl group COOH is re moved form the substrate as a molecule of CO2 the rest are preparation reactions in which molecules undergo rearrangements and other changes so that they can undergo further dehydrogenations or decarboxylations Overview of the Citric Acid Cycle for every glucose two acetyl groups enter the citric acid cy cle Each two carbon group combines with a four carbon compound oxalo acetate to form the six carbon compound citrate Two CO2 molecules are removed and energy is captured as one ATP three NADH and one FADH2 per acetyl group 8 3 Energy Yield of Nutrients Other Than Glucose Deamination a process in which amino acids are metabolized by reactions in which the amino group is the first removed Beta Oxidation process by which fatty acids are converted to acetyl CoA in the mitochon drial matrix 8 4 Anaerobic Respiration And Fermentation Anaerobic Respiration which does not use oxygen as its final electron acceptor is per formed by some prokaryotes that live in anaerobic environments waterlogged soil stagnant ponds animal intestines as in aerobic electrons are transferred from glucose to NADH they then pass down an electron transport chain that is couples to ATP synthesis by chemiosmosis part of the nitrogen cycle Fermentation an anaerobic pathway that does not involve an electron transport chain during fermentation only 2 ATP s are formed per glucose the resulting negatively reduced organic molecules tend to be toxic to the cells and are waste products Yeasts are facultative anaerobes that carry out aerobic respiration when oxygen is available but switch to alcohol fermentation when deprived of oxygen certain fungi and bacteria perform lactate lactic acid fermentation exploited by humans to make yogurt etc pg 190 CH 8 REVIEW also google difference between anaerobic and aerobic wtf