Ch. 8 Warm-Up – Unit 1 Test Review

1. Ch. 8 Warm-Up – Unit 1 Test Review FRQ: • Break essay’s apart by a, b, c • Can not add more of unwanted information and expect more points. • Example: • Wanted: 3 Properties of Water with details • Gave: Partial Details on 5

2. Peer Review Review Ch 8 Metabolism Notes with a your partner.

3. Chapter 8 An Introduction to Metabolism

4. What You Need To Know: • Energy moves through biological organisms and systems. Growth, reproduction and maintenance of the organization of living systems require energy and matter. • Energy input into a system must be constant or greater than energy lost. Big Idea #2

5. Vocabulary You should Know: • Metabolism • Ek • Ep • Chemical Energy • Catabolic Pathways • Anabolic Pathways PollEv.

6. Thermodynamics is the study of energy transformations that occur in nature • A closedsystem, such as liquid in a thermos, is isolated from its surroundings. Will eventually reach equilibrium. • In an opensystem, energy and matter can be transferred between the system and its surroundings. Organisms are open systems

7. The First Law of Thermodynamics • The energy of the universe is constant • Energy can be transferred and transformed • Energy cannot be created or destroyed • Also called the principle of Conservation of Energy

8. The Second Law of Thermodynamics • Every energy transfer or transformation increases the entropy ∆S (disorder) of the universe • During every energy transfer or transformation, some energy is unusable, often lost as heat

9. The free-energy change of a reaction tells us whether or not the reactions occurs spontaneously. • Free energy: part of a system’s energy available to perform work • G = change in free energy • Exergonic reaction: energy is released • Spontaneous reaction • G < 0 • Endergonic reaction: energy is required • Absorb free energy • G > 0

11. ∆G = ∆ H - T ∆S Free Energy • During a spontaneous change • Free energy decreases and the stability of a system increases • For a spontaneous reaction to occur: • Loss of enthalpy (Heat) ∆H -or- • Loss of order (Gain in entropy) ∆S -or both • Note: Temperature is measured in Kelvin

12. ∆G = ∆ H - T ∆S • Free energy is less than zero. • Loss of enthalpy (Heat) - ∆H • Loss of order (Gain in entropy) - ∆S

13. Practice Question • Calculate the Gibbs free energy change (G) for the following chemical reaction: ATP > ADP + Pi • The reaction occurs at 68 °F, the change in heat (H) = 19,070 cal, and the change in entropy (S) = 90 cal/K. °C = (°F – 32) * 5/9 °F = °C * 9/5 + 32 K = °C + 273

14. Practice Answer • 68 °F = 293 K, therefore the equation is set up in the following way: • G = H – TS • G = 19,070 cal – (293 K) (90 cal/K) • G = –7300 cal = –7.3 kcal

15. When ∆G is negative, is the system more or less stable? More Stable. Less free energy. Energy is leaving the system. Less likely to change.

16. Watch Bozeman Video:Gibbs Free Energy

17. Organisms use various metabolic pathways to MAX free energy • Ectothermic animals – allow the cellular environment to fluctuate with the external environment. • Endothermic animals – maintain a cellular environment that is different from the external environment, requires higher metabolic rate • Smaller animals = faster metabolism • Don’t ALWAYS reproduce to conserve energy (plants and animals)

18. Cells manage energy resources to do work by energy coupling: using an exergonic process to drive an endergonic one.

19. When the bonds between the phosphate groups are broken by hydrolysis  energy is released • This release of energy comes from the chemical change to a state of lower free energy, not in the phosphate bonds themselves The phosphate group causes conformational change of transport protein allowing ions to pump across the membrane. • A cell does three main kinds of work: • Mechanical • Transport • Chemical

20. Regeneration of ATP • Catabolic pathways regenerate ATP from ADP + Phosphate

21. Today’s Activity:Metabolism Packet - IndependentChrome Book and Head Phones HW: Begin making study tools. Quizlet. Kahoot. NoteCards. Re-write notes with pictures.

23. Warm-Up PollEVE • What happens to free energy as a reaction proceeds toward equilibrium? • Free energy increases. • Free energy decreases. • Free energy stays the same. • Free energy goes to jail.

24. Today’s Big Idea #4 Competition and Cooperation are important aspects of biological systems. - Interactions affect structure and function. - Cooperative interactions promote efficiency.

25. The Butterfly Brief (Article) Warm Up

26. Substrate Specificity of Enzymes • The reactant that an enzyme acts on is called the enzyme’s substrate • The enzyme binds to its substrate, forming an enzyme-substrate complex • The active site is the region on the enzyme where the substrate binds

27. Catalysts speed up metabolic reactions by lowering the activation energy (Ea)(energy needed to start reaction) get over energy barrier

31. INDUCED FIT: ENZYME FITS SNUGLY AROUND SUBSTRATE -- “CLASPING HANDSHAKE”

32. An enzyme’s activity can be affected by: • temperature • pH • Chemicals (Salinity) *DENATURE*

33. Cofactors • Cofactorsare nonprotein enzyme helpers such as minerals and metal ions (eg. Zn, Fe, Cu) • Coenzymesare organic cofactors (eg. vitamins) Enzyme Inhibitors • Competitive inhibitor: binds to the active siteof an enzyme, competes with substrate • Noncompetitive inhibitor: binds to another partof an enzyme  enzyme changes shape  active site is nonfunctional

34. Inhibition of Enzyme Activity

35. Regulation of Enzyme Activity • Allosteric Enzymes: Are proteins with quaternary structure so they have more than one binding site • Allosteric enzymes change shape between active and inactive shapes as a result of the binding of substrates at the active site, and of regulatory molecules at other sites. • Allosteric regulation: regulatorymolecule binds to site other than active site • Activator – stabilizes active enzyme • Inhibitor – stabilizes inactive form of enzyme

37. Cooperativity and Allostery • Cooperativity– one substrate triggers shape change in other active sites (conformational change)  increase catalytic activity • Example: Oxygen and Hemoglobin • At low substrate concentration, the enzyme is in the inactive form. • As the substrate concentration increases, substrate binds to enzyme and triggers a conformation change to the active shape of the enzyme. • After the first substrate is bound, the second and subsequent substrates all bind more readily. This is termed "cooperativity" • The result of the change to the active shape is a steep increase in both substrate binding, and as a result, in reaction rate over a narrow range of substrate concentration. • When all active sites on the allosteric enzyme are occupied with substrate, a plateau is reached.

38. Positive Feedback(Allosteric regulation) • One enzyme which is responsible for generating a product.. It increases the activity of another enzyme. • Ex: Oxygen to Hemoglobin, enhances oxygen affinity

39. Feedback Inhibition(Allosteric Inhibition) • The end product of a metabolic pathway shuts it down • Binds to the allosteric site of an enzyme • Prevent wasting chemical resources, increase efficiency of cell

40. Feedback Inhibition Examples 3. 1. Strychnine, a convulsant poison in pesticides, acts as an allosteric inhibitor of the glycine receptor in the brain – Causing convulsions 2. Protease inhibitors used to treat retroviral infections such as HIV

42. Positive and Negative Feedback

43. How to Name Enzymes • Change the ending on the name of the substrate to –ase • Sucrose (substrate) – Sucrase (enzyme) • Lipid – Lipase • Protein – Protease • DNA - DNAse

44. Conclusion: Factors that affect Rate of Reactions • Substrate concentration (Increase, plateau) • Enzyme concentration (Increase, will saturate) • Inhibitors (Slow reactions)

45. Watch Bozeman Video:Enzymes

46. Test Your Knowledge • If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to A. Add more enzyme B. Heat the solution C. Add more substrate D. Add an allosteric inhibitor E. Add a noncompetitive inhibitor

47. Self Quiz – Test Your Knowledge 2. If an enzyme is added to a solution where its substrate and product are in equilibrium, what would occur? A. Additional product would be formed. B. Additional substrate would be formed. C. The reaction would change from endergonic to exergonic. D. The free energy of the system would change. E. Nothing; the reaction would stay at equilibrium

48. Self Quiz – Test Your Knowledge 3. Some bacteria are metabolically active in hot springs because A. They can maintain lower internal temperatures B. High temperatures make catalysts unnecessary. C. Their enzymes have high optimal temperatures. D. Their enzymes are insensitive to temperature.

49. Which of the following involves a decrease in entropy? • A) condensation reactions • B) reactions that separate monomers • C) depolymerization reactions • D) hydrolysis reactions

50. Anabolic pathways _____. A) are usually highly spontaneous chemical reactions B) consume energy to build up polymers from monomers C) release energy as they degrade polymers to monomers D) consume energy to decrease the entropy of the organism and its environment