1. BELLRINGER #1…  Explain the 4 structures of a protein.  Where are proteins made?

2. Answers to Bellringer…  Primary= amino acid structure  Secondary = alpha helices and beta sheets; HYDROGEN BONDING creates these folds and coils  Tertiary = forms 3D structure  R groups (side chains) on amino acids bind together Ionic bonds, Van der Waals forces, Disulfide bridges, Hydrogen bonding  Quartnary = 2+ polypeptides bond together (NOT ALL PROTEINS); different protein DOMAINS are created-each can do a different fxn (ex: hemoglobin protein)

3. Answers to Bellringer… (Part 2)  Proteins are made on ribosomes  FREE RIBOSOMES= make proteins that are used INSIDE cell  ATTACHED RIBOSOMES (to Rough ER) = make proteins that are shipped out of cell and used elsewhere in organism

4. BELLRINGER #2…  How do you determine the rate of reaction for this enzyme?

6. http://www.hippocampus.org/Biology;js essionid=0F877174B8F739BC8C8FE6 29659CA510

7. How does HEAT affect an enzyme?

8. How does pH affect an enzyme?  http://www.phschool.com/science/b iology_place/labbench/lab2/ph.html http://www.phschool.com/science/b iology_place/labbench/lab2/ph.html

9. Chapter 8: Part 1 ENERGY An Introduction to Metabolism AP Biology Ms. Gaynor

10. Metabolism  An organism’s metabolism transforms matter and energy  follows the laws of thermodynamics  Metabolism Sum of ALL of an organism’s chemical reactions

11. Metabolic Pathways  A metabolic pathway has many steps begin w/ a specific molecule and end with a product each pathway catalyzed by many different enzymes Enzyme 1Enzyme 2Enzyme 3 A B C D Reaction 1Reaction 2Reaction 3 Starting molecule Product

12. Metabolic Pathways and Enzyme Inhibition  Competitive inhibitors mimic the substrate and compete for the active site.  Non-competitive inhibitors bind to enzyme away from active site  cause a change in the active site

14. Regulation of Enzyme Activity  A cell’s metabolic pathways must be tightly regulated Regulating enzymes help CONTROL metabolism  Allosteric Regulation when a protein’s function at one site is affected by binding of a regulatory molecule at another site

15. http://bcs.whfreeman.com/thelifewire/content/chp06/06020 02.html

16. Allosteric Regulation & Enzymes  Regulatory molecules bind to enzyme’s allosteric site  changing shape of enzyme.  Allosterically regulated enzymes have a quaternary protein structure  Each subunit of the enzyme has an active site and an allosteric site.  Allosteric activators stabilizes active site  Allosteric inhibitors deactivates active site.

17. Negative Feedback inhibition Active site available Isoleucine used up by cell Feedback inhibition Isoleucine binds to allosteric site Active site of enzyme 1 no longer binds threonine; pathway is switched off Initial substrate (threonine) Threonine in active site Enzyme 1 (threonine) Intermediate A Intermediate B Intermediate C Intermediate D Enzyme 2 Enzyme 3 Enzyme 4 Enzyme 5 End product (isoleucine) The end product of a metabolic pathway shuts down the pathway

18. 2 Types Metabolic Pathways  Catabolic pathways Break down complex molecules into simpler compounds Release energy  Ex: Cellular Respiration  A nabolic pathways (“ a dd”) Build complicated molecules from simpler ones Sometimes called “biosynthetic pathways” Consume energy  Ex: Building protein from amino acids

19. Forms of Energy  Energy the capacity to cause change Exists in various forms  thermal (heat)  Chemical (potential)  kinetic

20. 2 Main Types of Energy  Kinetic energy the energy of movement Type of energy that can do work  Potential energy energy of position (stored energy) Ex: chemical energy  energy stored in a [ ] gradient, membrane potential *Energy can be converted from one form to another

21. The Laws of Energy Transformation  Thermodynamics study of energy transformations (changes)  Closed vs. open systems Closed  isolated from surroundings Open (i.e-organisms)  energy can be transferred from organism to surroundings  Absorb energy (light or chemical from organic molecules)  release heat and metabolic waste products (CO 2 )  2 laws of thermodynamics

22. The 1 st Law of Thermodynamics  According to the 1 st law of thermodynamics Energy cannot be created or destroyed ONLY transferred and transformed Also known as the principle of energy conservation

23. An example of energy conversion Figure 8.3 First law of thermodynamics: Energy can be transferred or transformed but Neither Neither created nor destroyed. For example, the chemical (potential) energy in food will be converted to the kinetic energy of the cheetah’s movement in (b). Chemical energy Eating food  food has stored potential energy!

25. The 2 nd Law of Thermodynamics  According to the 2 nd law of thermodynamics With every energy transfer, entropy is increased  Entropy = disorder (or randomness) Some energy becomes unusable  released as heat

26. An example of 2 nd Law of Thermodynamics Second law of thermodynamics: Every energy transfer or transformation increases the disorder (entropy) of the universe. For example, disorder is added to the cheetah’s surroundings in the form of heat and the small molecules that are WASTE of metabolism. Heat co 2 H2OH2O +

27. DECOMPOSITION also increases enthropy

28. How is this connected to the 10% rule? No chemical rxn is 100% efficient b/c not all energy is converted into work

29. 2 nd Law of Thermodynamics TOTAL ENERGY = usable energy + unusable energy Potential/Kinetic + Heat  Entropy = increase in disorder The unusable energy  Enthalpy = increase in order The usable energy When energy is converted from one form to another, some is becomes unusable!

30. Unusable energy usually equal THERMAL energy (heat)

31. Free-Energy known as “G”  A living system’s free energy Usable energy that can do work Known as Gibb’s Free Energy  Needed to maintain healthy cell growth, division, etc.

32.  The change in free energy, ∆G during a biological process Is related directly to the enthalpy change (∆H) and the change in entropy ∆H= total energy (usable + unusable energy) ∆S = change in entropy T = absolute temp (K) ∆G = ∆H – T∆S

33. Cellular Respiration & Metabolism INPUT OF ENERGY (ATP)…MOR E ORDER! WASTE AND HEAT OUTPUT… MORE DISORDER!!! COMPACT/ STORED ENERGY = ORDERED INCREASE IN ENTHALPY INCREASE IN ENTROPY USED ENERGY = LESS ORDERED

34. Why is ∆G helpful?  It tells us if a chemical rxn will occur spontaneously without input of energy Negative ∆G occurs spontaneously (loses free energy) + or zero ∆G  rxn never spontaneous

35. Free Energy and Metabolism 2 types of Reactions in Metabolism 1.Exergonic (Exothermic) 2.Endergonic (Endothermic)

37. Exergonic and Endergonic Reactions in Metabolism  An exergonic reaction (- ∆G ) Proceeds with a net release of free energy and IS spontaneous Reactants Products Energy Progress of the reaction Amount of energy released (∆G <0) Free energy (a ) Exergonic reaction: energy released

38.  Endergonic reactions (+ ∆G ) absorbs free energy from its surroundings and is NOT spontaneous Stores free energy in molecules Figure 8.6 Energy Products Amount of energy released (∆G>0) Reactants Progress of the reaction Free energy (b) Endergonic reaction: energy required Madnitude of G  Represents amt of energy needed to drive rxn

40. Real Life Examples…  Exergonic (Exothermic) Cellular Respiration Energy (ATP) is released when glucose is broken down  Endergonic (Endothermic) Photosynthesis Energy (ATP) is NEEDED (consumed) to put together glucose from CO 2, H 2 0 and sunlight http://flightline.highline.edu/jbetzzall/BI100/animations/e nergy_changes.html http://flightline.highline.edu/jbetzzall/BI100/animations/e nergy_changes.html

41. Coupled Reactions http://www.hippocampus.org/AP%20Biology%20II Watch Central Catabolic Pathways (Metabolism)

42.  A cell does three main kinds of work Mechanical = ex: movement Transport = ex: active cell membrane transport Chemical = ex: the pushing of endergonic rxn’s ATP powers cellular work by coupling exergonic rxns to endergonic rxns

43. The Structure and Hydrolysis of ATP  ATP (adenosine triphosphate) Is the cell’s energy shuttle (molecule) Provides energy for cellular functions It is renewable RNA nucleotide O O O O CH 2 H OH H N HH O N C HC N C C N NH 2 Adenine Ribose 3 Phosphate groups O O O O O O - --- CH

44.  Energy is released from ATP When the terminal phosphate bond is broken Exergonic rxn (G= -7.3 kcal/mol) PO 4 -3 create instability P Adenosine triphosphate (ATP) H2OH2O + Free Energy  given off Inorganic phosphate + Adenosine diphosphate (ADP) PP PPP i Sometimes referred to as “high energy” phosphate bonds

45. ATP  an “energy currency” Example of Energy Coupling

46.  ATP hydrolysis (splitting of ATP) Can be coupled to other reactions Endergonic reaction: ∆G is positive, reaction is not spontaneous ∆G = +3.4 kcal/mol Glu ∆G = + 7.3 kcal/mol ATP H2OH2O + + NH 3 ADP + NH 2 Glutamic acid Ammonia Glutamine Exergonic reaction: ∆ G is negative, reaction is spontaneous P Coupled reactions: Overall ∆G is negative; together, reactions are spontaneous ∆G = –3.9 kcal/mol

47. How ATP Performs Work  ATP drives endergonic reactions By phosphorylation, which is transferring a phosphate (PO 4 3-) to other molecules (reactant becomes “phosphorylated”)  More reactive (less stable) with PO 4 3- on it  acts as an intermediate in many rxns