1. End Show Slide 1 of 20 AP Biology 9-17-15 Begin Immediately on your multiple choice test…you have approximately 30 minutes Complete the essay IN PEN for the remaining 16 minutes Tests must be completed in class. NO HW TONIGHT!!

2. End Show Slide 2 of 20 AP Biology 9-18-15 Test Analysis (Fri-Thu in tutorials) HW- Due Mon Grade essay using highlighters for weekend Begin Metabolism Lecture Complete 1 st free energy question in Free energy packet Period 5 10:30 – 12:24

3. End Show Slide 3 of 20 AP Biology 9-21-15 Test Analysis (Mon-Thu in tutorials or Buff Time) Agenda 1.Lecture: Energy & Metabolism 2.Bozeman: Bioenergetics HW- Bozeman: ATP: Adenosine Triphosphate

4. End Show Slide 4 of 20 AP Biology 9-22-15 REMEMBER….Test Analysis (Mon-Thu in tutorials or Buff Time) AGENDA: Lab: Toothpickase Get a lab and a box of toothpicks Make your toothpick piles as directed in the lab HW: Finish Lab

5. Introduction to Metabolism

6. Metabolism is the sum of an organism’s chemical reactions Metabolism is an emergent property of life that arises from interactions between molecules within the cell

7. A metabolic pathway begins with a specific molecule and ends with a product The product of one reaction is substrate of the next Each step is catalyzed by a specific enzyme BIOCHEMICAL PATHWAY BIOCHEMICAL PATHWAY VIDEO

8. ENZYMES THAT WORK TOGETHER IN A PATHWAY CAN BE Soluble with free floating intermediates Covalently bound in complex Attached to a membrane in sequence Concentrated in specific location

9. CATABOLIC PATHWAY (CATABOLISM) Release of energy by the breakdown of complex molecules to simpler compounds EX: digestive enzymes break down food ANABOLIC PATHWAY (ANABOLISM) consumes energy to build complicated molecules from simpler ones EX: linking amino acids to form proteins

10. Forms of Energy ENERGY = capacity to cause change Energy exists in various forms (some of which can perform work) Energy can be converted from one form to another

11. KINETIC ENERGY – energy associated with motion –HEAT (thermal energy) is kinetic energy associated with random movement of atoms or molecules POTENTIAL ENERGY = energy that matter possesses because of its location or structure –CHEMICAL form of potential energy stored in chemical bonds in molecules

12. On the platform, the diver has more potential energy. Diving converts potential energy to kinetic energy. Climbing up converts kinetic energy of muscle movement to potential energy. In the water, the diver has less potential energy.

13. THERMODYNAMICS = the study of energy transformations CLOSED system (EX: liquid in a thermos) = isolated from its surroundings OPEN system energy + matter can be transferred between the system and its surroundings Organisms are open systems

14. The First Law of Thermodynamics = energy of the universe is constant –Energy can be transferred and transformed –Energy cannot be created or destroyed The first law is also called the principle of CONSERVATION OF ENERGY

15. The Second Law of Thermodynamics During every energy transfer or transformation entropy (disorder) of the universe INCREASES some energy is unusable, often lost as heat

16. Chemical energy Heat CO 2 First law of thermodynamics Second law of thermodynamics H2OH2O ORGANISMS are energy TRANSFORMERS!

17. Equation that describes energy of a system ∆G = ∆H - T∆S https://www.youtube.com/watch?v=huKBuShAa1w Free-Energy Change (  G) can help tell which reactions will happen ∆G = change in free energy ∆H = change in total energy (enthalpy) or change ∆S = entropy T = absolute temperature in degrees Kelvin

18. Exergonic and Endergonic Reactions in Metabolism EXERGONIC reactions (- ∆G) Release energy are spontaneous ENDERGONIC reactions (+ ∆G) Absorb energy from their surroundings are non-spontaneous

19. End Show Slide 19 of 20 Exergonic Reaction Only processes with a negative ∆G are spontaneous Spontaneous processes can be harnessed to perform work

20. Concept 8.3: ATP powers cellular work by coupling exergonic reactions to endergonic reactions In the cell, the energy from the exergonic reaction of ATP hydrolysis can be used to drive an endergonic reaction Overall, the coupled reactions are exergonic

21. Phosphate groups Ribose Adenine ATP (adenosine triphosphate) is the cell’s renewable and reusable energy shuttle ATP provides energy for cellular functions Energy to charge ATP comes from catabolic reactions

22. Adenosine triphosphate (ATP) Energy PP P PP P i Adenosine diphosphate (ADP) Inorganic phosphate H2OH2O + +

23. P i ADP Energy for cellular work provided by the loss of phosphate from ATP Energy from catabolism (used to charge up ADP into ATP ATP + -adding phosphate group stores energy; -removing it releases energy

24. NH 2 Glu P i P i P i P i NH 3 P P P ATP ADP Motor protein Mechanical work: ATP phosphorylates motor proteins Protein moved Membrane protein Solute Transport work: ATP phosphorylates transport proteins Solute transported Chemical work: ATP phosphorylates key reactants Reactants: Glutamic acid and ammonia Product (glutamine) made + + +

25. Every chemical reaction between molecules involves bond breaking and bond forming ACTIVATION ENERGY = amount of energy required to get chemical reaction started Activation energy is often supplied in the form of heat from the surroundings IT’S LIKE PUSHING A SNOWBALL UP A HILL... Once you get it up there, it can roll down by itself Free energy animation

26. Transition state CD A B EAEA Products CD A B  G < O Progress of the reaction Reactants C D A B Free energy The Activation Energy Barrier

27. CATALYST = a chemical agent that speeds up a reaction without being consumed by the reaction ENZYMES = biological catalysts Most enzymes are PROTEINS Exception = ribozymes (RNA)

28. Course of reaction without enzyme E A without enzyme  G is unaffected by enzyme Progress of the reaction Free energy E A with enzyme is lower Course of reaction with enzyme Reactants Products ENZYMES ENZYMES work by LOWERING ACTIVATION ENERGY;LOWERING ACTIVATION ENERGY

29. ENZYMES LOWER ACTIVATION ENERGY BY: –Orienting substrates correctly –Straining substrate bonds –Providing a favorable microenvironment Enzymes change ACTIVATION ENERGY but NOT energy of REACTANTS or PRODUCTS

30. ENZYMES Most are proteins Lower activation energy Specific Shape determines function Re-usable Unchanged by reaction

31. The REACTANT that an enzyme acts on = SUBSTRATE Enzyme + substrate = ENZYME-SUBSTRATE COMPLEX Region on the enzyme where the substrate binds = ACTIVE SITE Substrate held in active site by WEAK interactions (ie. hydrogen and ionic bonds ) ENZYMES are UNCHANGED & REUSABLE

32. TWO MODELS PROPOSED LOCK & KEY Active site on enzyme fits substrate exactly INDUCED FIT Binding of substrate causes change in active site so it fits substrate more closely

33. –General environmental factors, such as temperature, pH, salt concentration, etc. –Chemicals that specifically influence the enzyme See a movie Choose narrated Enzyme Activity can be affected by :

34. TEMPERATURE & ENZYME ACTIVITY Each enzyme has an optimal temperature at which it can function (Usually near body temp)

35. Higher temperatures = more collisions among the molecules so increase rate of a reaction BUT.. Above a certain temperature, activity begins to decline because the enzyme begins to denature. So rate of chemical reaction increases with temperature up to optimum, then decreases

36. pH and ENZYME ACTIVITY Each enzyme has an optimal pH at which it can function Extremes in pH and temp can DENATURE enzymes -causing them to unwind/lose their 3-D TERTIARY structure -breaks hydrogen, ionic bonds; NOT covalent peptide bonds

37. End Show Slide 37 of 20 Many enzymes require helpers: COFACTORS = non-protein enzyme helpers EX: Zinc, iron, copper (minerals)

38. End Show Slide 38 of 20 COENZYMES = organic enzyme helpers Ex: vitamins

39. SUBSTRATE CONCENTRATION & ENZYME ACTIVITY V MAX ← Adding substrate increases activity up to a point

40. REGULATION OF ENZYME PATHWAYS GENE REGULATION cell switches on or off the genes that code for specific enzymes

41. REGULATION OF ENZYME PATHWAYS FEEDBACK INHIBITION end product of a pathway interacts with and “turns off” an enzyme earlier in pathway prevents a cell from wasting chemical resources by synthesizing more product than is needed FEEDBACK INHIBITION

42. NEGATIVE FEEDBACK –Switches off pathway when product is plentiful –Common in many enzyme reactions –Saves energy: don’t make it if you don’t need it B A C D Enzyme 1 Enzyme 2 Enzyme 3 D D D D D D D D DD C B A Negative feedback Example: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway

43. POSITIVE FEEDBACK (less common) –The end product speeds up production WW X Y Z Z Z Z Z Z Z Z Z Z Z ZZ Z ZZ Z Z Z Y X Enzyme 4 Enzyme 5 Enzyme 6 Enzyme 4 Enzyme 5 Enzyme 6 Positive feedback EXAMPLE: Chemicals released by platelets that accumulate at injury site, attract MORE platelets to the site.

44. REGULATION OF ENZYME ACTIVITY ALLOSTERIC REGULATION protein’s function at one site is affected by binding of a regulatory molecule at another site Allosteric regulation can inhibit or stimulate an enzyme’s activity Allosteric enzyme inhibition

45. SOME ALLOSTERIC ENZYMES HAVE MULTIPLE SUBUNITS Each enzyme has active and inactive forms The binding of an ACTIVATOR stabilizes the active form The binding of an INHIBITOR stabilizes the inactive form

46. COOPERATIVITY = form of allosteric regulation that can amplify enzyme activity Binding of one substrate to active site of one subunit locks all subunits in active conformation

47. COMPETITIVE inhibitor REVERSIBLE; Mimics substrate and competes with substrate for active site on enzyme ENZYME ANIMATION Enzyme Inhibitors

48. NONCOMPETITIVE inhibitors bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective ENZYME ANIMATION