This comprehensive study guide covers all the key concepts in AP Biology Unit 3, focusing on cellular energetics. We'll delve into the intricate processes of energy transformation within cells, equipping you with the knowledge and understanding needed to excel in your studies.
Understanding Energy and Metabolism
This section lays the groundwork for the entire unit. We will explore the fundamental concepts related to energy and its role in biological systems.
Key Concepts:
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Energy: What is energy? Define kinetic and potential energy, and provide biological examples of each. Understand the laws of thermodynamics – specifically how they apply to living systems. Discuss the concept of free energy (Gibbs Free Energy, ΔG) and its significance in determining the spontaneity of reactions. How do endergonic and exergonic reactions relate to ΔG?
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Metabolism: Define metabolism, catabolism, and anabolism, and give examples of each. Understand how metabolic pathways are regulated (feedback inhibition, allosteric regulation). Explain the role of enzymes as biological catalysts. Describe enzyme structure, function, and the factors that affect enzyme activity (temperature, pH, substrate concentration). What are cofactors and coenzymes, and how do they function?
Cellular Respiration: Harvesting Chemical Energy
Cellular respiration is the central process by which cells extract energy from glucose. This section will break down the intricate steps involved.
Key Concepts:
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Glycolysis: Detail the steps of glycolysis, including its inputs and outputs (ATP, NADH, pyruvate). Where does glycolysis occur in the cell? Discuss the different fates of pyruvate under aerobic and anaerobic conditions.
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Pyruvate Oxidation: Explain the process of pyruvate oxidation, including the production of acetyl-CoA, NADH, and CO2. Where does this process take place?
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Krebs Cycle (Citric Acid Cycle): Describe the steps of the Krebs cycle, highlighting the production of ATP, NADH, FADH2, and CO2. Understand the importance of the cycle in generating reducing power (NADH and FADH2). Where does the Krebs cycle occur?
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Oxidative Phosphorylation (Electron Transport Chain & Chemiosmosis): This is the most energy-producing stage. Detail the electron transport chain, explaining the role of electron carriers, proton pumping, and the establishment of a proton gradient. Explain chemiosmosis and the synthesis of ATP via ATP synthase. Understand the role of oxygen as the final electron acceptor. How many ATP molecules are produced per glucose molecule through cellular respiration?
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Anaerobic Respiration & Fermentation: Explain the processes of alcoholic and lactic acid fermentation. How do these processes generate ATP in the absence of oxygen? Compare and contrast aerobic respiration and fermentation in terms of ATP production and efficiency.
Photosynthesis: Capturing Light Energy
This section will explore how plants and other photosynthetic organisms convert light energy into chemical energy.
Key Concepts:
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Photosynthetic Pigments: Describe the role of chlorophyll and other photosynthetic pigments in absorbing light energy. Explain the absorption spectrum and action spectrum.
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Light-Dependent Reactions: Detail the steps of the light-dependent reactions, including photosystem II, photosystem I, electron transport, ATP synthesis (photophosphorylation), and NADPH production. What is the role of water in the light-dependent reactions?
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Light-Independent Reactions (Calvin Cycle): Explain the steps of the Calvin cycle, including carbon fixation, reduction, and regeneration of RuBP. Understand the role of ATP and NADPH from the light-dependent reactions in the Calvin cycle. What is the overall product of the Calvin cycle?
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C4 and CAM Photosynthesis: Discuss the adaptations of C4 and CAM plants to arid environments. How do these photosynthetic pathways differ from C3 photosynthesis?
Putting it All Together
This final section will tie together the concepts of cellular respiration and photosynthesis, highlighting their interconnectedness and importance in the biosphere. Consider the flow of energy and matter between these two processes. Discuss the overall energy balance of these metabolic pathways.
This study guide provides a solid foundation for mastering AP Biology Unit 3. Remember to consult your textbook, class notes, and other resources to further enhance your understanding. Good luck!
