Study Guide Exam 2 PDF

Chapter 5. Simplified Study Guide: Membranes and Transport 1\. Fluid Mosaic Model Definition: The cell membrane is made up of a flexible layer of phospholipids with proteins floating in it, resembling a mosaic. 2\. Phospholipids Behavior Amphipathic: Phospholipids have a hydrophilic (water-...

Chapter 5. Simplified Study Guide: Membranes and Transport 1\. Fluid Mosaic Model Definition: The cell membrane is made up of a flexible layer of phospholipids with proteins floating in it, resembling a mosaic. 2\. Phospholipids Behavior Amphipathic: Phospholipids have a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails. Arrangement: They form a bilayer with heads facing outward and tails facing inward. 3\. Temperature & Fatty Acid Composition Higher Temperature: Increases fluidity (more movement). Unsaturated Fatty Acids: Increase fluidity due to kinks that prevent tight packing. Saturated Fatty Acids: Decrease fluidity because they pack tightly. 4\. Cholesterol's Role Function: Cholesterol stabilizes the membrane by maintaining fluidity---preventing it from being too rigid or too fluid. 5\. Membrane Proteins Functions Transport: Help move substances in and out of the cell. Receptors: Receive signals from outside the cell. Enzymes: Catalyze reactions at the membrane. 6\. Movement Across Membranes Easily Cross: Small nonpolar molecules (like O2, CO2). Need Transport Proteins: Large or charged molecules (like glucose and ions). 7\. Types of Passive Transport Simple Diffusion: Movement of small molecules directly through the membrane. Facilitated Diffusion: Movement of larger molecules through protein channels. 8\. Diffusion vs. Osmosis Diffusion: Movement from high to low concentration. Osmosis: Movement of water from low solute concentration to high solute concentration. 9\. Tonicity Terms Hypertonic: Higher solute concentration outside the cell; water moves out (cell shrinks). Hypotonic: Lower solute concentration outside the cell; water moves in (cell swells). 10\. Active Transport vs. Passive Transport Active Transport: Moves substances against their concentration gradient and requires energy (ATP). Passive Transport: Moves substances down their concentration gradient without energy. 11\. Co-Transport Definition: The simultaneous transport of two substances across a membrane. One substance moves with its gradient while the other moves against it. 12\. Bulk Transport Endocytosis: Cell takes in large materials by engulfing them (e.g., phagocytosis for solids). Exocytosis: Cell expels materials using vesicles that fuse with the membrane. CHAPTER 6 1\. Catabolic vs. Anabolic Reactions Catabolic Reactions: Break down larger molecules into smaller ones, releasing energy (e.g., cellular respiration). Anabolic Reactions: Build larger molecules from smaller ones, requiring energy (e.g., protein synthesis). 2\. Types of Energy Potential Energy: Stored energy (e.g., energy in chemical bonds). Chemical Energy: A form of potential energy stored in molecular bonds (e.g., glucose). Kinetic Energy: Energy of motion (e.g., moving molecules). Thermal Energy: Energy associated with heat; a form of kinetic energy related to molecular motion. Heat: Energy transferred due to temperature differences; not usable for work. 3\. Entropy Definition: A measure of disorder or randomness in a system. Example: In a closed system, entropy increases as energy is dispersed (e.g., ice melting). Ordered State of Life: Living organisms maintain order by using energy (e.g., from food) to counteract increasing entropy. 4\. Free Energy Definition: The energy available to do work in a system. Reaction Prediction: If products have lower free energy than reactants, the reaction is likely to proceed (spontaneous). Exergonic Reactions: Release free energy (e.g., cellular respiration). Endergonic Reactions: Require free energy (e.g., photosynthesis). 5\. Spontaneous Reactions Definition: Reactions that occur without external input; they increase the entropy of the universe. Spontaneity vs. Rate: A reaction can be spontaneous but slow (e.g., rusting iron). 6\. Reaction Coupling Definition: Linking an exergonic reaction with an endergonic reaction to drive the latter. Energy Source: The energy released from an exergonic reaction (e.g., ATP hydrolysis) is used to power endergonic reactions. 7\. Role of ATP Function: ATP (adenosine triphosphate) is the primary energy carrier in cells. It stores energy in its high-energy phosphate bonds and releases energy when hydrolyzed to ADP. 8\. Enzymes and Chemical Reactions Function: Enzymes speed up reactions by lowering activation energy. Substrate Binding: Substrates bind to the active site of the enzyme; the enzyme can be reused multiple times. 9\. Reaction Rates and Energy Levels Transition State Energy: If the energy level of the transition state decreases, the reaction rate increases. Enzyme Changes: Addition/Removal: Adding or removing enzymes will affect reaction rates. Inhibitors: Competitive inhibitors block active sites, slowing reactions; non-competitive inhibitors change enzyme shape, also slowing reactions. 10\. Activation Energy and Regulation Activation Energy: The energy needed to start a reaction; enzymes lower this barrier, allowing for easier regulation of metabolic pathways. Here's a simplified study guide based on the key concepts from Chapter 7 Learning Goals: CHAPTER 7 1\. Relationship Between Cellular Respiration and Photosynthesis Overview: Photosynthesis converts light energy into chemical energy (glucose) using carbon dioxide and water, while cellular respiration breaks down glucose to release energy for cellular processes. Chemical Equation for Cellular Respiration:  2\. Energy Change Diagram Diagram: Show glucose and oxygen as reactants and carbon dioxide, water, and ATP as products, indicating a release of energy during the reaction. 3\. Redox Reactions Oxidation: Loss of electrons (or increase in oxidation state). Reduction: Gain of electrons (or decrease in oxidation state). Oxidizing Agent: Substance that gains electrons and is reduced. Reducing Agent: Substance that loses electrons and is oxidized. 4\. Redox Reactions in Cellular Processes Combustion: Similar to cellular respiration, involves the oxidation of fuel (e.g., glucose) producing carbon dioxide and water. Cellular Respiration: Involves redox reactions where glucose is oxidized and oxygen is reduced. 5\. Function of NAD NAD (Nicotinamide adenine dinucleotide) acts as an electron carrier, becoming NADH when it gains electrons during metabolic reactions, which is crucial for energy production in cellular respiration. 6\. Major Steps of Cellular Respiration Glycolysis: Location: Cytoplasm Reactants: Glucose Products: 2 pyruvate, 2 ATP, 2 NADH Pyruvate Oxidation: Location: Mitochondrial matrix Reactants: 2 pyruvate Products: 2 Acetyl-CoA, 2 NADH, 2 CO2 Citric Acid Cycle (Krebs Cycle): Location: Mitochondrial matrix Reactants: 2 Acetyl-CoA Products: 4 CO2, 6 NADH, 2 FADH2, 2 ATP Oxidative Phosphorylation: Location: Inner mitochondrial membrane Reactants: NADH, FADH2, O2 Products: ATP, H2O 7\. ATP Generation Substrate-Level Phosphorylation: Direct transfer of phosphate to ADP to form ATP (occurs in glycolysis and citric acid cycle). Oxidative Phosphorylation: ATP synthesis powered by the transfer of electrons through the electron transport chain, utilizing the proton gradient. 8\. Effects of Oxygen Supply Anaerobic Conditions: When oxygen is scarce, cells switch to anaerobic respiration (e.g., fermentation) to produce ATP, resulting in the buildup of lactic acid or ethanol instead of CO2 and water. 9\. Response to Oxygen Demand Anaerobic Conditions: ATP production is less efficient, leading to fatigue during intense exercise. Cells may switch to anaerobic pathways (e.g., lactic acid fermentation). 10\. Impact of Circulatory System Changes Effect on Cellular Respiration: Any disruption (like reduced blood flow) can lead to decreased oxygen delivery, impairing aerobic respiration, leading to reliance on anaerobic pathways, reducing ATP yield. CHAPTER 8 1\. Flow of Matter and Energy Autotrophs: Organisms (like plants) that produce their own food through photosynthesis, converting light energy into chemical energy (glucose). Heterotrophs: Organisms (like animals) that obtain energy by consuming autotrophs or other heterotrophs. Flow: Energy from the sun is captured by autotrophs through photosynthesis, producing glucose, which is then consumed by heterotrophs, transferring energy and matter through food chains. 2\. Structure of Leaves and Chloroplasts Leaves: Broad, flat surfaces maximize light absorption. Chloroplasts: Contain chlorophyll and have a double membrane structure with thylakoids (where light reactions occur) and stroma (site of the Calvin cycle). Maximizing Capacity: The arrangement of chloroplasts in leaves allows for optimal light capture and gas exchange. 3\. Net Reaction for Photosynthesis Chemical Equation:  Tracing Atoms: The carbon in glucose originates from carbon dioxide, while oxygen comes from water. 4\. Stages of Photosynthesis Light Reactions: Convert solar energy into chemical energy (ATP and NADPH). Location: Thylakoid membranes. Calvin Cycle: Uses ATP and NADPH to convert CO2 into glucose. Location: Stroma. Interdependence: Light reactions produce energy carriers that power the Calvin cycle. 5\. Light Absorption and Energy Harvesting Light Wavelengths: Different pigments (like chlorophyll) absorb different wavelengths, mainly blue and red light. Absorption Spectrum: Graphs show how much light is absorbed at different wavelengths, indicating which pigments are present and how they affect photosynthesis. 6\. Chlorophyll Excitation Excitation by Photons: Chlorophyll absorbs light energy, exciting electrons to a higher energy state, which can then be used in photosynthesis. Returning to Ground State: When excited electrons fall back to their original state, energy is released, often as heat or light. 7\. Photosystems Location: Embedded in the thylakoid membranes. Function: Capture and transfer light energy to drive the electron transport chain. 8\. Energy and Matter Flow Electron Transport Chain: Energized electrons from photosystems are passed along a series of proteins, releasing energy used to pump protons into the thylakoid lumen, creating a proton gradient. ATP and NADPH Production: ATP synthase uses the proton gradient to synthesize ATP, while electrons ultimately reduce NADP+ to NADPH. 9\. Water Splitting Reaction Support for Photosynthesis: Water is split into oxygen, protons, and electrons during light reactions. Products: O2 is released as a byproduct, and electrons replenish those lost by chlorophyll. 10\. Calvin Cycle Three Phases: Carbon Fixation: CO2 is added to ribulose bisphosphate (RuBP). Reduction: ATP and NADPH convert 3-PGA to G3P (sugar). Regeneration: RuBP is regenerated to continue the cycle. Need for ATP and NADPH: Required for the energy and reducing power to convert CO2 into glucose. 11\. Comparison of Photosynthesis and Cellular Respiration Electron Carriers: Both processes use electron carriers (NADPH in photosynthesis, NADH in respiration) to transport electrons. Electron Transport Concentration Gradients: Both create gradients (protons in photosynthesis and respiration) to drive ATP synthesis via ATP synthase. 12\. Citric Acid Cycle vs. Calvin Cycle Citric Acid Cycle: Produces ATP, NADH, and FADH2 from the breakdown of glucose (a catabolic process). Calvin Cycle: Uses ATP and NADPH to synthesize glucose (an anabolic process). 13\. Predicting Changes in Closed Systems Plant-Only System: CO2 levels decrease, O2 levels increase. Animal-Only System: CO2 levels increase, O2 levels decrease. Mixed System: Balanced levels depending on the ratio of plants to animals. !