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# Chapter 8 Notes **Metabolism** uses enzymes to catabolize organic molecules to precursor molecules that cells then use to anabolize larger, more complex molecules. **Three Pathways of Primary Catabolism:** * **Glycolysis** * **Krebs Cycle** * **Respiratory chain - electron transport and o...

# Chapter 8 Notes **Metabolism** uses enzymes to catabolize organic molecules to precursor molecules that cells then use to anabolize larger, more complex molecules. **Three Pathways of Primary Catabolism:** * **Glycolysis** * **Krebs Cycle** * **Respiratory chain - electron transport and oxidative phosphorylation** **Aerobic respiration**: relies on oxygen. **Anaerobic respiration**: uses NO3-, SO42-, CO32-, and other oxidized compounds as final electron acceptors. **Fermentation**: is incomplete oxidation of glucose (- oxygen isn't required) **Glycolysis**: * All 3 metabolic strategies begin with glycolysis * Glucose oxidized into 2 molecules of pyruvic acid * 2 NADH and 2 ATP generated **The Electron Transport Chain**: * A chain of special redox carriers * Embedded in the cytoplasmic membrane in bacteria **Catabolism of Noncarbohydrates**: * **Complex polysaccharides**: broken into component sugars, which can enter glycolysis * **Lipids**: broken down by lipases; fatty acids undergo beta oxidation, whose products can enter the Krebs cycle as acetyl CoA * **Proteins**: broken down into amino acids by proteases; amino groups are removed through deamination. **General notes**: * Component parts of bacteria are being synthesized on a continuous basis. * Catabolism is also taking place as long as nutrients are present and the cell is nondormant. * Catabolic processes provide all of the energy for complex building reactions.