ap biology unit 3 study guide

2 min read 02-02-2025

This comprehensive study guide covers AP Biology Unit 3, focusing on cellular energetics. We'll delve into the intricate processes of energy conversion within cells, equipping you with the knowledge and understanding needed to excel in your studies. Remember to consult your textbook and class notes for additional details and specific examples.

I. Introduction to Energy and Metabolism

Energy: Define energy and its various forms relevant to biological systems (kinetic, potential, chemical). Understand the relationship between free energy (Gibbs Free Energy, ΔG), enthalpy (ΔH), and entropy (ΔS). Be able to predict the spontaneity of reactions based on these thermodynamic parameters.
Metabolism: Define metabolism and differentiate between catabolic and anabolic pathways. Understand how these pathways are interconnected and regulated.
Enzymes: Discuss the role of enzymes as biological catalysts. Explain enzyme-substrate specificity, the active site, and the factors that influence enzyme activity (temperature, pH, inhibitors, activators). Describe the different types of enzyme inhibition (competitive, non-competitive). Understand allosteric regulation and feedback inhibition.

Key Terms: Gibbs Free Energy, Enthalpy, Entropy, Catabolism, Anabolism, Enzyme, Active Site, Substrate, Competitive Inhibition, Non-Competitive Inhibition, Allosteric Regulation, Feedback Inhibition.

II. Cellular Respiration

Overview: Understand the overall equation for cellular respiration and its significance. Describe the four main stages: glycolysis, pyruvate oxidation, the Krebs cycle (citric acid cycle), and oxidative phosphorylation (electron transport chain and chemiosmosis).
Glycolysis: Detail the steps of glycolysis, including energy investment and energy payoff phases. Identify the net ATP, NADH, and pyruvate produced. Understand the regulation of glycolysis.
Pyruvate Oxidation: Describe the conversion of pyruvate to acetyl-CoA, including the production of NADH and CO2.
Krebs Cycle: Explain the steps of the Krebs cycle, highlighting the production of ATP, NADH, FADH2, and CO2. Understand the cycle's role in generating reducing power for oxidative phosphorylation.
Oxidative Phosphorylation: Describe the electron transport chain and chemiosmosis, including the role of ATP synthase in ATP production. Explain the concept of proton gradient and its importance in driving ATP synthesis. Understand the final electron acceptor (oxygen) and the production of water.

Key Terms: Glycolysis, Pyruvate Oxidation, Krebs Cycle (Citric Acid Cycle), Oxidative Phosphorylation, Electron Transport Chain, Chemiosmosis, ATP Synthase, Proton Gradient.

III. Fermentation

Anaerobic Respiration: Understand the process of fermentation as an alternative to aerobic respiration in the absence of oxygen. Differentiate between alcoholic fermentation and lactic acid fermentation. Describe the products of each type of fermentation.
Significance: Explain the importance of fermentation in various organisms and its limitations in ATP production compared to cellular respiration.

Key Terms: Alcoholic Fermentation, Lactic Acid Fermentation.

IV. Photosynthesis

Overview: Understand the overall equation for photosynthesis and its significance. Describe the two main stages: the light-dependent reactions and the Calvin cycle (light-independent reactions).
Light-Dependent Reactions: Explain the process of light absorption by chlorophyll and other pigments. Describe the electron transport chain in the thylakoid membrane, including the generation of ATP and NADPH. Understand photolysis (splitting of water) and oxygen production.
Calvin Cycle: Explain the steps of the Calvin cycle, including carbon fixation, reduction, and regeneration of RuBP. Understand the role of ATP and NADPH in driving the Calvin cycle and the production of glucose.

Key Terms: Photosynthesis, Light-Dependent Reactions, Calvin Cycle, Chlorophyll, Photolysis, RuBP.

V. Connecting Cellular Processes

Relationship between Cellular Respiration and Photosynthesis: Explain how cellular respiration and photosynthesis are interconnected in terms of energy flow and the cycling of carbon and oxygen. Understand their roles in maintaining the Earth's atmosphere.

This study guide provides a solid framework for your AP Biology Unit 3 review. Remember to practice applying your knowledge through diagrams, problem-solving, and past exam questions. Good luck with your studies!