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Metabolism

Metabolism. Basic Concepts and Design. Metabolism. What is metabolism? all the chemical reactions that take place in cells series of energy transformations Why do living organism require energy? to synthesize large molecules from small ones to move substances in and out of cells

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Metabolism

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  1. Metabolism Basic Concepts and Design

  2. Metabolism • What is metabolism? • all the chemical reactions that take place in cells • series of energy transformations • Why do living organism require energy? • to synthesize large molecules from small ones • to move substances in and out of cells • muscle contraction and cell movement

  3. Metabolism • What is the difference between phototrophs and chemotrophs? • phototrophs obtain energy from sunlight • chemotrophs obtain energy from breaking chemical bonds • What is the difference between anabolic and catabolic reactions? • catabolic – fuels degraded to release useful energy • anabolic – energy used to synthesize biomolecules

  4. Metabolism • Why are reactions often coupled in metabolic pathways? • to insure that the overall free energy change is negative • a reaction that requires energy may be paired with one that releases energy

  5. Metabolism • What is the role of ATP in cells? • donor of free energy in energy requiring reactions • Why is ATP an energy rich molecule?

  6. Metabolism • What are the factors that contribute to the large amount of energy released when ATP is hydrolzed? • resonance stabilization • electrostatic repulsion • ease of hydration

  7. Metabolism

  8. Metabolism • What do we mean by phosphoryl transfer potential? • ability to donate a phosphate group • What molecules besides ATP can transfer PO4 groups?

  9. Metabolism • How is ATP regenerated in cells?

  10. Metabolism • The oxidation of which of these two molecules will produce more ATP and why?

  11. Metabolism • How do molecules with high phosphoryl transfer potential couple the oxidation of carbon to the synthesis of ATP? • glyceraldehyde-3-PO4 + NAD+ + HPO4 1,3 biphosphoglycerate + NADH + H+ • 1,3 biphosphoglycerate + ADP  3-phosphoglyceric acid + ATP

  12. Metabolism

  13. Metabolism • What is happening at each stage of catabolism?

  14. Metabolism • While ATP is an activated carrier of phosphoryl groups, what molecule(s) is (are) activated carrier(s) of electrons during oxidation? • nicotinamine adenine dinucleotide (NAD) • flavin adenine dinucleotide (FAD)

  15. Metabolism

  16. Metabolism

  17. Metabolism • One H is transferred to NAD with 2 electrons and the other H goes into solution as a proton.

  18. Metabolism

  19. Metabolism

  20. Metabolism • What activated carrier for electrons is used in most biosynthetic reactions or the reaction shown above? • NADPH

  21. Metabolism • Why is coenzyme A an important molecule in metabolism? • carrier of acyl groups

  22. Metabolism

  23. Metabolism • While metabolism consists of thousands of reactions, each reaction falls into one of six categories.

  24. Oxidation-Reduction Reaction

  25. Ligation Reaction

  26. Isomerization Reaction

  27. Group Transfer Reaction

  28. Hydrolytic reaction

  29. Addition or Removal of Functional Groups

  30. Regulation of Metabolism • What are the three basic ways in which metabolic reactions are regulated? • controlling amount of enzyme • influencing rate of transcription • altering catalytic activity • allosterically • covalent modification • controlling accessibility of substrates

  31. Regulation of Metabolism • How do hormones influence metabolism? • alteration of enzyme activity • glucagon and glycogen phosphorylase • What other factors influence metabolism? • compartmentalization • energy status of cell

  32. Metabolism • What do ATP, NADH, FAD and coenzyme A have in common and what does this indicate about these molecules? • adenosine diphosphate • evolved from early RNA catalysts

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