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Metabolism

Metabolism. Chapter 7. Metabolism:. Metabolism: refers to the entire network of chemical processes involved in maintaining life. Energy metabolism: the ways that the body obtains and spends energy from food.

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Metabolism

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  1. Metabolism Chapter 7 Metabolism: FON 241; L. Zienkewicz

  2. Metabolism: • Metabolism: refers to the entire network of chemical processes involved in maintaining life. • Energy metabolism: the ways that the body obtains and spends energy from food. Metabolism: FON 241; L. Zienkewicz

  3. Anabolism:The building of compounds from small molecules into larger ones. Energy is used for this process to take place. • Catabolism:The breakdown of molecules into smaller units. Energy is releasedin this process. • Ex: Glucose catabolism results in the release of CO2 and H2O Metabolism: FON 241; L. Zienkewicz

  4. ATP (Adenosine Triphosphate): • The main energy source of cells. • Used for muscular contractions, enzyme activity, etc. • Catabolism results in the production of many ATP molecules: energy. • Used by the body when energy is needed. • Hydrolysis breaks the bonds in ATP, thus releasing energy. Metabolism: FON 241; L. Zienkewicz

  5. Metabolic Efficiency: • Food energy is converted to ATP with approximately 50% efficiency. • The other 50% is released as heat. • When ATP is needed for energy, ~50% are used. • Overall: 25% of food becomes energy 75% is released as heat. Metabolism: FON 241; L. Zienkewicz

  6. The Cell: Q: Approximately how many cells does the human body contain? A: 1x1014 cells or 100,000,000,000,000. (100 trillion cells) Metabolism: FON 241; L. Zienkewicz

  7. The Cell: • The site for metabolic activity. • Liver cells are the most metabolically active. Metabolism: FON 241; L. Zienkewicz

  8. How is energy produced? Three stages: 1. Proteins, Carbohydrates and Fats are broken down during digestion and absorption into smaller units: AA’s monosaccharides and fatty acids. 2. These smaller compounds are further broken down into 2-carbon compounds. 3. Compounds are degraded into CO2 and H20. Metabolism: FON 241; L. Zienkewicz

  9. Helpers in reactions: • Enzymes: proteins that facilitate chemical reactions without being changed in the process; protein catalysts. • Coenzymes: assist enzymes in their activities. Metabolism: FON 241; L. Zienkewicz

  10. Breakdown of nutrients for energy: • Glucose breakdown • Glycerol and Fatty Acid breakdown • Amino Acid breakdown Fats Energy Carbohydrates Common Pathway Protein Metabolism: FON 241; L. Zienkewicz

  11. 1. Glucose breakdown Glycolysis: A reaction in which glucose is degraded to pyruvate; net profit: 2 ATP. An anaerobic pathway. Glucose Pyruvate Lactic Acid Acetyl CoA 2 ATP Less oxygen available Oxygen available Metabolism: FON 241; L. Zienkewicz

  12. The path from Pyruvate to Acetyl CoA is NOT reversible. Metabolism: FON 241; L. Zienkewicz

  13. Metabolism: FON 241; L. Zienkewicz

  14. 2. Glycerol and Fatty Acid breakdown Triglycerides are broken into:Glycerol and Fatty Acids (lipolysis). Glucose Glycerol Pyruvate Fatty acids Acetyl CoA Metabolism: FON 241; L. Zienkewicz

  15. 3. Amino Acid breakdown Glucose Amino Acids Pyruvate Amino Acids Acetyl CoA Amino Acids TCA Cycle Metabolism: FON 241; L. Zienkewicz

  16. 3. Amino Acid breakdown (cont.) • Deamination: AA Keto acid and Ammonia • Transamination • Ammonia Urea in the Liver • Urea excreted via the kidneys • Water needed for urea excretion Metabolism: FON 241; L. Zienkewicz

  17. The TCA Cycle: • Functions to convert Acetyl CoA to CO2 and to produce energy. • Oxaloacetate combines with Acetyl CoA to begin the cycle. • The result: produces potential ATP (energy). Metabolism: FON 241; L. Zienkewicz

  18. The Electron Transport Chain: • The primary site for ATP (energy) synthesis. • Uses Oxygen to convert products of the TCA cycle into energy. Metabolism: FON 241; L. Zienkewicz

  19. Why is fat higher in energy? • Fat’s carbon-hydrogen bonds can be easily oxidized, yielding energy (ATP). • 1 glucose molecule yields 38 ATP when oxidized. • 1 fatty-acid (16-C) will yield 129 ATP when oxidized. Metabolism: FON 241; L. Zienkewicz

  20. Weight Maintenance: • Dietary fat can be easily transformed into body fat. • Surplus protein leads to: 1. Replacing daily losses. 2. Increased protein oxidation (energy). 3. Storage as fat. • Surplus carbohydrate leads to: 1. Storage as glycogen. 2. Increased CHO oxidation (variable w/ diet). 3. Storage as fat. Metabolism: FON 241; L. Zienkewicz

  21. The body’s #1 priority: • Meet its energy needs. Metabolism: FON 241; L. Zienkewicz

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