Concept 6.1 ATP and Reduced Coenzymes Play Important Roles in Biological Energy Metabolism. 1. Energy is stored in the, and it can be released

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1 Chapter 6 Reading Guide Pathways that Harvest and Store Chemical Energy Name Concept 6.1 ATP and Reduced Coenzymes Play Important Roles in Biological Energy Metabolism 1. Energy is stored in the, and it can be released and transformed by the of living cells. 2. What are the 5 general principles governing metabolic pathways? 3. According to the laws of thermodynamics, a biochemical reaction may change the of energy by not the net. 4. Define exergonic and endergonic reactions. 5. What does it mean to say that biological reactions in the cell are coupled in time and location? 6. What is a coenzyme? 7. Molecules are required to be the carries of the energy that is coupled. What are the two widely used coenzymes? 8. List a few examples of processes in the cell that are exergonic and a few processes that are endergonic. 1

2 9. Label the following diagram showing the structure of ATP. Below it write the reaction for the hydrolysis of ATP. 10. Write the reaction for the hydrolysis of ATP. What is the a ΔG for this reaction? 11. Write the equation for the hydrolysis of ADP. Where have you seen this reaction before? 2

3 12. Pictured below is a molecule of ATP. The bonds between the phosphates (called a phosphoanhydride bond) is show as a wavy instead of straight. Explain why this is drawn in terms of the energy in the bonds of both ATP and P i. Your answer should explain the ΔG of the reaction you showed above. STOP HERE & WATCH: Bozeman ATP What is a redox reaction? Define reduction and oxidation. 14. For each of the reactions which reactants get oxidized and which get reduced? - C 6 H 12 O O 2 6 CO H 2 O - 6 CO H 2 O C 6 H 12 O O In redox reactions, the compound that gives up electron to the other compound is the. The compound that receives electrons from another compound is the. 16. In our biological processes, we will identify redox reactions as the gain or loss of hydrogen atoms. Show a representation of why this is possible. 17. In general, the more a molecule is, the more energy is stored in its covalent bonds. STOP HERE & WATCH: Bozeman Redox Reactions 3

4 18. NAD is considered an electron carrier. Explain the reduction and oxidation reactions involving NAD. 19. How much energy is released in the oxidation of NADH? How does it compare to the hydrolysis of ATP? 20. What other molecules can be used as electron carriers in biological processes? Concept 6.2 Carbohydrate Catabolism in the Presence of Oxygen Releases a Large Amount of Energy 21. What is cellular respiration and what is the reaction that represents the process. (Include the amount of energy.) 22. What are the 3 linked biochemical pathways that occur to catabolize glucose in aerobic conditions? 23. Glycolysis: a.) Where it takes place: b.) How many individual reactions are involved: c.) Reactants: d.) Products: e.) 2 Stages: f.) 2 Types of Reactions: g.) Where Pyruvates go for further catabolism: 4

5 24. Conversion of Pyruvate to Acetyl CoA: a.) How many times it occurs per glucose molecule: b.) Reactant: c.) Initial Products (per pyruvate): d.) Acetate is bound to to form e.) Process the acetyl CoA molecules feed into: 25. Citric Acid Cycle (Also called Kreb s Cycle): a.) How many reactions: b.) How many times it occurs per glucose molecule: c.) Molecule that feeds into the cycle: d.) Why it is called a cycle? e.) Overall products (per acetyl CoA) 26. Where is the NADH and the FADH 2 that are produced during glycolysis, conversion of pyruvate and the citric acid cycle used? STOP & READ Handout: Oxidative Phosphorylation vs. Substrate-Level Phosphorylation 27. Describe the overall process of oxidative phosphorylation. 28. What is the respiratory chain and where is its location? 29. Describe the process of electron transport that occurs in the respiratory chain. 5

6 30. The oxidation of NADH and FADH2 is coupled with reduction reactions. What substance is reduced and what is the product? Write the redox reaction. 31. Also embedded in the cell membrane is an enzyme called. This enzyme is used to make ATP through a process called. Define chemiosmosis below: 32. Why must the H+ ions go through ATP synthase instead of just diffusing through the membrane. 33. Use the following diagram to describe the structure and function of ATP synthase. 6

7 34. From an evolutionary perspective, what is notable about ATP synthase and the process of chemiosmosis? Does where this process takes place provide support or negate the endosymbiotic theory? 35. What would be the result of damage to the membrane across which chemiosmosis takes place? 36. A total of 32 molecules of ATP can be produced from one glucose molecule. Account for the origins of each of these molecules. 37. Explain the vital role of O 2. STOP HERE & WATCH: Bozeman Cellular Respiration Answer the following Analyze the Data using the figure on page 114. Is the reaction an oxidation or reduction? Is the reaction exergonic or endergonic? This reaction requires a coenzyme. What kind of coenzyme? What happens to fumarate after the reaction is complete? What happens to the coenzyme after the reaction is completed? 7

8 Concept 6.3 Carbohydrate Catabolism in the Absence of Oxygen Releases a Small Amount of Energy 39. What does the word anaerobic mean? 40. Explain, from a chemistry perspective, why fermentation may become necessary in an organism s cells. 41. What is the maximum amount of ATP that can be made per glucose during fermentation and why is this product limited? 42. Fill in the follow table to summarize the two fermentations pathways. Lactic Acid Fermentation Alcoholic Fermentation Location in the Cell End Product Electron Acceptor Organisms that Do It Reversible? (Can the end product can be converted back to pyruvate when O 2 is present?) 8

9 Concept 6.4 Catabolic and Anabolic Pathways Are Integrated 43. Label the following diagram so that you understand how energy sources other than glucose feed into the process of cellular respiration. 44. Ultimately, all energy used by living organisms derived from. 45. Write the two reactions representing the linked processes of cellular respiration and photosynthesis. 9

10 Concept 6.5 During Photosynthesis, Light Energy Is Converted to Chemical Energy 46. What is the definition and general process of photosynthesis? 47. What type of reactions are similar in glucose catabolism (cellular respiration) and photosynthesis? 48. Describe the two pathways in photosynthesis: 49. You many also see the carbon-fixation reactions called dark reactions. Why can calling these reactions dark reactions be misleading? 50. Where do these reactions take place in prokaryotes and in plants? 51. What are the two ways that can be used to describe the behavior of light? If this is confusing to you- watch Bozeman Wave-Particle Duality of Light (More info than you need but helpful) 52. What are the three things that can happen to a photon of light when it meets a molecule? 53. When a photon of light is absorbed by a molecule and acquires the energy of the photon, it is raised from a (with energy) to an (with energy). The addition of this new energy boosts on the the electrons within the molecule into an electron shell from its nucleus making the molecule and more. 10

11 54. What are pigments? 55. What is the difference between an absorption spectrum and an action spectrum? Use the graph below to identify the line that represents each. 56. What 2 pigments in plants are responsible for the absorption of photons to drive the light reactions? (You do not have to know their structure or structural differences.) What wavelengths of light do they absorb? 57. Plants possess that absorb photons intermediate in energy between the red and the blue wavelengths, and then transfer a portion of that energy to the. 58. What are some examples of these accessory pigments? 11

12 REFERENCE DIAGRAM 59. Use the following diagram to explain the structure of a photosystem. 12

13 60. Summarize what happens to the energy that is absorbed by chlorophyll in the photosystem. 61. The electrons that leave the chlorophyll in the reaction center are passed along a series of electron acceptors. What is this system similar to and what is the final electron acceptor that gets reduced? 62. There are 2 photosystems in the thylakoid membrane involved in the light reactions. Describe each, noting the difference in where the excited electrons end up. 63. When looking at photosynthesis as a process from start to finish, the location where it starts is in Photosystem II. Explain what happens to the excited electrons and and how the chlorophyll that gave up the electrons gets electrons back. 64. Photosystem I is the next area of action in the photosynthesis chain of events. Why/how is photosystem I linked to photosystem II? 65. Ultimately the ATP and NADPH that are produced in the light reactions will provide the energy needed for the dark (light independent reactions) however a specific ratio of ATP to NADPH is needed. Using the electron transport chain and ATP synthase is one way ATP is produced but there is a second way that creates more ATP and no NADPH called cyclic electron transport. Which photosystem is used in cyclic electron transport? 13

14 66. Trace the flow of electrons in noncyclic electron transport in the chloroplast and compare it with that of cyclic electron transport. (See Figure 6.20) Noncyclic Transport Cyclic Transport 67. Overall, what are the reactants and products of the light reactions of photosynthesis? 68. Write equations for the production of the following in photosynthesis, and indicate whether they are oxidations, reductions are neither. Concept 6.6 Photosynthetic Organisms Use Chemical Energy to Convert CO 2 to Carbohydrates 69. How is the energy produced (ATP & NADPH) in the light reactions used? 70. Summarize the three distinct processes in the Calvin cycle. (See figure to label on next page) 14

15 71. What are the 2 possible fates of the G3P that is not recycled back into RuBP and on what conditions do each depend? 72. Define autotrophs. Self feeders - photosynthsizers 73. Define heterotroph. Other feeders STOP & WATCH: Bozeman Photosynthesis Also: Bozeman Photosynthesis & Respiration Crash Course Photosynthesis: 15