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The most important metabolic fuel in the human body is: A. Sucrose B. Starch C. Protein

The most important metabolic fuel in the human body is: A. Sucrose B. Starch C. Protein D. Cellulose E. Glucose. When two monosaccharides undergo a condensation reaction: A. a new monosaccharide is formed B. a disaccharide is formed C. a polysaccharide is formed

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The most important metabolic fuel in the human body is: A. Sucrose B. Starch C. Protein

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  1. The most important metabolic fuel in the human body is: A. Sucrose B. Starch C. Protein D. Cellulose E. Glucose

  2. When two monosaccharides undergo a condensation reaction: A. a new monosaccharide is formed B. a disaccharide is formed C. a polysaccharide is formed D. a starch is formed E. hydrolysis occurs

  3. Metabolism & Enzymes • Constraints on Reactions • Making Reactions Possible with ATP • Making Reactions Probable with Enzymes • Why does Grandma take St. Joseph’s?

  4. What is Metabolism? • All the chemical reactions of the body

  5. What is Metabolism? • All the chemical reactions of the body • Catabolism • breaking large molecules into smaller molecules (hydrolysis) • releases energy (an exergonic process)

  6. What is Metabolism? • All the chemical reactions of the body • Catabolism • breaking large molecules into smaller molecules (hydrolysis) • releases energy (an exergonic process) • Anabolism • builds a large molecule from smaller ones (dehydration synthesis/condensation) • consumes energy (an endergonic process)

  7. Metabolism & Enzymes • Constraints on Reactions • Making Reactions Possible with ATP • Making Reactions Probable with Enzymes • Why does Grandma take St. Joseph’s?

  8. Constraints on Reactions • First Law of Thermodynamics • Energy can be converted from one form to another, but it cannot be created or destroyed • Chemical energy is stored in macromolecules we eat • When bonds are broken, energy is released • We use this energy to power our bodies

  9. Constraints on Reactions • First Law of Thermodynamics • Energy can be converted from one form to another, but it cannot be created or destroyed • Chemical energy is stored in macromolecules we eat • When bonds are broken, energy is released • We use this energy to power our bodies • Second Law of Thermodynamics • In every energy transfer, some energy is lost as heat • Unless our bodies obtain energy from our surroundings, we lose energy over time (entropy)

  10. To counter the loss of energy (as heat), we add energy to our bodies in the form of food

  11. Using ATP to Build Macromolecules

  12. Using ATP to Build Macromolecules endergonic exergonic exergonic

  13. ATP is Recycled (Breakdown of food)

  14. Metabolism & Enzymes • Constraints on Reactions • Making Reactions Possible with ATP • Making Reactions Probable with Enzymes • Why does Grandma take St. Joseph’s?

  15. Enzymes are Everywhere

  16. Enzymes are Biological Catalysts • Enzymes are proteins that function as biological catalysts • Increase the speed of chemical reactions • Increase likelihood of chemical reactions

  17. Enzymes are Biological Catalysts • Enzymes are proteins that function as biological catalysts • Increase the speed of chemical reactions • Increase likelihood of chemical reactions • Can increase rate of chemical reactions by over 1,000,000X

  18. Enzymes Bind to Substrates • Bind with one or more reactants, termed substrates

  19. Enzymes Bind to Substrates • Bind with one or more reactants, termed substrates • Enzymes are named after the substrate with which they bind • -ase forms the suffix (e.g., the enzyme amylase digests the starch amylose)

  20. How do Enzymes Work? • Enzymes can affect reactions by: 1) Placing reactants in proper orientation 2) Create environment that promotes the reaction 3) Chemically weakening the bonds within the reactants 4) Donating electrons or protons to the reactants

  21. How do Enzymes Work? • Enzymes can affect reactions by: 1) Placing reactants in proper orientation 2) Create environment that promotes the reaction 3) Chemically weakening the bonds within the reactants 4) Donating electrons or protons to the reactants • Enzymes catalyze specific reactions

  22. How do Enzymes Work? • Enzymes can affect reactions by: 1) Placing reactants in proper orientation 2) Create environment that promotes the reaction 3) Chemically weakening the bonds within the reactants 4) Donating electrons or protons to the reactants • Enzymes catalyze specific reactions • Enzymes are reusable (i.e. recycled)

  23. Enzymatic Reactions

  24. Cofactors • Cofactors bind to enzyme and change its shape, creating an active site (e.g., iron, copper, zinc, magnesium or calcium ions)

  25. Cofactors • Cofactors bind to enzyme and change its shape, creating an active site (e.g., iron, copper, zinc, magnesium or calcium ions) • Vitamins are used to make organic cofactors called coenzymes. • Many enzymes cannot function without cofactors.

  26. Rate of Enzymatic Reactions • The basis for chemical reactions is molecular and collision Molecular Motion Animation

  27. Rate of Enzymatic Reactions • Rates of reactions are affected by various factors: • Substrate and enzyme concentration • Temperature • pH • Why do these influence reaction rates?

  28. Enzyme Enzyme/Substrate Concentration • Slow at low concentration

  29. Enzyme Enzyme/Substrate Concentration • Slow at low concentration • Increase until point of saturation • Why does saturation occur?

  30. Temperature • Slow at low temperatures Reaction Rate Temperature (°C)

  31. Temperature • Slow at low temperatures • Slow at high temperatures • Explain rate at each arrow Reaction Rate Temperature (°C)

  32. pH • Enzymes function best within a specific pH range • Why does pH alter enzyme function?

  33. Competitive Inhibition • Slow down enzyme function • Effect is reversible Substrate Active Site Inhibitor Enzyme Enzyme

  34. Non-Competitive Inhibition • Binds to enzyme away from active site Substrate Enzyme Inhibitor

  35. Non-Competitive Inhibition • Binds to enzyme away from active site • Substrate no longer binds to active site • Irreversible damage to enzyme function • - Mercury, Cyanide Substrate Enzyme Inhibitor

  36. Metabolism & Enzymes • Constraints on Reactions • Making Reactions Possible with ATP • Making Reactions Probable with Enzymes • Why does Grandma take St. Joseph’s?

  37. Aspirin is a Non-Competitive Inhibitor • Inhibits COX enzyme, which functions in blood platelet aggregation • What do blood platelets do? • Hence, Aspirin reduces risk of a heart attack

  38. Patient Profile: Laurie • Ate a Cheese Omelet, Blueberry yogurt, and 2 glasses of chocolate milk at IHOP • Symptoms: Diarrhea, Nausea, Stomach Ache • What do you think Laurie suffers from?

  39. Summary • Building macromolecules, is an anabolic process that requires energy released from the catabolism of adenosine triphosphate (ATP) • Enzymes bring together reactants and create an environment that favors a reaction • Like any protein, the structure of an enzyme is critical to its function. Environmental conditions, cofactors, and inhibitors alter the structures of enzymes and hence alter their functions

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