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AP Bio: Tuesday, 9.27.11 Metabolic Reactions & Enzymes

AP Bio: Tuesday, 9.27.11 Metabolic Reactions & Enzymes

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AP Bio: Tuesday, 9.27.11 Metabolic Reactions & Enzymes

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  1. AP Bio: Tuesday, 9.27.11Metabolic Reactions & Enzymes • Homework: • Pass PS 4 to the front to be collected • PS 5 due a week from today • Do Now: • Today is a lecture/notes day… take out a notebook (title for today is at the top of the slide) • The following terms can be divided into two logical categories. Split them as best you can into two lists. Endergonic Synthesis Condensation Exergonic Decomposition Hydrolysis Catabolism Cellular respiration Anabolism Photosynthesis

  2. Today’s Agenda & Goals • Agenda: • Lecture on Metabolic Reactions & Enzymes • Goals: • Distinguish between endergonic and exergonic reactions • Describe the role of ATP in metabolic reactions • Explain the role of enzymes as biological catalysts

  3. Video #1: Energy in Living Things • 1st Law of Thermodynamics: Energy can’t be created or destroyed, it only changes forms. • Forms of energy – • Potential (stored) – includes chemical energy (energy held in chemical bonds) (ex: glucose, ATP, fatty acids) • Kinetic (movement) – includes heat energy (the most random/disordered form) • 2nd Law of Thermodynamics: Every energy transfer involves the “loss” of some energy as heat (so the total amount of “disordered” energy increases overall)

  4. Two categories of metabolic reactions… • Hydrolysis • Decomposition • Catabolism • Cellular respiration • Exergonic • Condensation • Synthesis • Anabolism • Photosynthesis • Endergonic

  5. How do cells power endergonic reactions? ATP

  6. ATP – Your cells’ rechargeable battery

  7. The ATP/ADP Cycle is coupled with other cellular reactions

  8. AP Bio: Wednesday, 9.28.11Metabolic Reactions & Enzymes (Day 2) • Homework: • Lab 2A Analysis Questions (page 3) • Lab 2B and 2C Pre-Lab (page 4) • Do Now: On the Lab 2 packet, read the Overview and answer the Pre-Lab Questions on pages 1-2. • Today’s Agenda: • Lab 2 Pre-Lab and Demonstration • Lecture (continued) – Enzymes

  9. Video #2: Controlling Cellular Metabolism

  10. Even exergonic reactions require activation energy.

  11. Catalysts lower the energy barrier.

  12. How do enzymes work? • Specificity – every enzyme’s shape matches its substrate • Substrate binds to enzyme’s active site • Induced fit – enzyme and substrate both change shape slightly • Bond strain lowers the EA needed to break substrate bonds • Substrate turns to product; enzyme remains unchanged

  13. Enzyme shape is essential!

  14. AP Bio: Thursday, 9.29.11Lab 2: Enzyme Catalysis • Homework: • Lab 2 Graphs and Analysis Questions • Do Now: Take out Lab 2 and turn to page 3. • Today’s Goals: • Quantitatively measure the rate of an enzyme-catalyzed reaction • Experimentally determine how temperature, pH, and substrate concentration affect the rate of an enzyme-catalyze reaction

  15. AP Bio: Thursday, 9.29.11Lab 2: Enzyme Catalysis • HW: Lab 2 (graphs and analysis questions) due Tuesday Prob Set 5 now due Wed. not Tuesday! Agenda: • Discussion: Part A and Pre-Lab for Parts B and C (5 min) • Demonstration of lab set-up (5 min) • Lab! Part B, then Part C • Today’s Goals: • Quantitatively measure the rate of an enzyme-catalyzed reaction • Experimentally determine how temperature, pH, and substrate concentration affect the rate of an enzyme-catalyze reaction

  16. AP Bio: Tuesday, 10/4/11Lab Debrief; Enzyme Regulation • Homework: • Problem Set 5 due Wednesday • Unit Test on Ch. 1-5 and 8 on TUESDAY (see review sheet) • Do Now: Take out Lab 2 and your graphs • Today’s Goals: • Analyze data from Lab 2 • Explain how enzyme activity is regulated in cells

  17. Video of Peroxidase in Action… • See Starr cd ch. 5 catalase

  18. Videos on Protein Shape…

  19. Enzyme Regulation

  20. Competitive Inhibition

  21. Non-Competitive Inhibition

  22. Allosteric Regulation

  23. Allosteric Regulation • A regulator must bind in order to activate the enzyme • Similar to, but opposite from, non-competitive inhibition

  24. FEEDBACK INHIBITION

  25. AP Bio: Wednesday, 10.5.11Unit 1 Test Review! • Homework: • Study for tomorrow’s test! • Do Now: • Take out PS 5 • Take 15-20 minutes to answer the practice questions in the packet • Objectives: • Review the material on the Unit 1 Test • Agenda: • Practice questions / Hand back PS 4 • Discuss practice questions & other review topics • Hand in PS 5