1. Ch.6: Introduction to Metabolism Metabolism, Transformation of energy, ATP laws of thermo-dynamics Enzymes, Controls of metabolism

2. YIKES!!! Metabolic pathways

3. What is Metabolism? Put the following words into one of these two categories: Anabolic Catabolic exergonic, endergonic, nonspontaneous, spontaneous, -ΔG, +ΔG, uphill, downhill, respiration, photosynthesis ATP  ADP + Pi, ADP + Pi  ATP loss of free energy (G), gain of free energy (G) products have greater G than reactants, reactants have greater G than products absorbs free energy from surroundings, releases free energy to surroundings hydrolysis, condensation/dehydration ΔG= -686 kcal/mol, ΔG= 686 kcal/mol C6H12O6 + O2  H20 + CO2, H20 + CO2  C6H12O6 + O2

4. What is Metabolism? Put the following words into one of these two categories: Anabolic Catabolic exergonic, endergonic, nonspontaneous, spontaneous, -ΔG, +ΔG, uphill, downhill, respiration, photosynthesis ATP  ADP + Pi, ADP + Pi  ATP loss of free energy (G), gain of free energy (G) products have greater G than reactants, reactants have greater G than products absorbs free energy from surroundings, releases free energy to surroundings hydrolysis, condensation/dehydration ΔG= -686 kcal/mol, ΔG= 686 kcal/mol C6H12O6 + O2  H20 + CO2, H20 + CO2  C6H12O6 + O2

6. ATP’s Structure It is a Nucleotide: Base Sugar Phosphates Hydrolysis of ATP into ADP

7. 10 million molecules of ATP/second/cell!

8. Energy Coupling: The use of an exergonic process to drive an endergonic reaction. Ex: Adding a phosphate group (Pi) to molecules makes them unstable and usually highly reactive Where does that Pi come from?

9. Example coupling reaction ATP’s phosphate makes GLU more reactive, this is phosphorylation/ energy coupling Exergonic Note: what is the second law of thermodynamics?

10. What about this example? A + B  AB ΔG = 9.0 kcal/mol ATP+ H2O  ADP+Pi ΔG = -7.3 kcal/mol

11. Using energy gradients (energy at each step) to help do work. Staying away from equilibrium. (like respiration!) how is a human an open system? Closed system Open system

12. What does free energy have to do with enzymes?

13. Enzymes Examples: hexokinase, sucrase, catalase, pepsin, trypsin ---all are specific enzyme Substrate(s) enzyme Product(s) The action can be catabolic or anabolic. “Induced fit” not rigid —like a hand shake http://scholar.hw.ac.uk/site/biology/activity7.asp?outline=no

14. Negative  G = a loss of free Energy The products have less energy than the reactants, EXERGONIC

15. Enzyme rate and rate of reaction How does the amount of enzyme affect the rate of the reaction? How does the amount of enzyme affect the rate of an enzyme? How does the amount of substrate affect the rate of the reaction? How does the amount of substrate affect the rate of the enzyme? What are the differences between competitive and noncompetitive inhibitors. What is cooperativity? How might this be involved with negative feedback?

17. Free Energy and Metabolism: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O  G = - 686 kcal/mol (-2870 kJ/mol) Is this Exergonic or Endergonic? What is this reaction? 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2  G = +686 kcal/mol (+2870 kJ/mol) This reaction is photosynthesis. Where is the Energy coming from to drive this nonspontaneous reaction?

18. Energy transformations 1. First law of thermodynamics: Conservation of energy—it is not lost or destroyed. There is a constant amount in the universe. (what form has the lowest Energy?) 2. Second law of thermodynamics: Entropy(S), every energy transfer increases entropy of the universe.

19. This change in Energy can be harnessed to do work! Kinetic (KE) and Potential energy (PE) G(free energy)=H(total Energy) –TS

20. Glen Canyon Dam in Arizona

21. Fig 6.12

22. Toothpickase Demonstration How many subunits does the enzyme have? __ What is the quaternary structure for your enzyme? ____________ Where is your active site? ______________ What are the products of the reaction of toothpickase with its substrate? __________ Is the enzyme changed in any way throughout the reaction? ________

23. Calculating the V-Max of toothpick- ase under normal conditions Time (in seconds) Toothpicks Metabolized 00 10 30 60 120

24. ENZYMES: pH and temperature sensitive Most will DENATURE when out of range

25. Competitive inhibitor Competes for the active site Non-competitive inhibitor Doesn’t compete with the active site

26. Allosteric enzymes: Activators and Inhibitors (active forms, inactive forms)

27. Fig 6.16 Feedback inhibition end product acting as an allosteric inhibitor Pathways switching off because of an end product acting as an allosteric inhibitor

28. Cooperativity: the substrate itself “turns the enzyme on” / activates it Allosteric again