Becker's World of the Cell, [GLOBAL EDITION]

Forcourses in cell biology. Connectingfundamental concepts across the world of the cell Known for its strong biochemistry coverage and clear, easy-to-followexplanations and figures, Becker’s World of the Cell provides abeautifully illustrated, up-to-date introduction to cell biology concepts,processes, and applications. Informed by years of classroom experience in thecell biology course, the text features accessible and authoritativedescriptions of all major principles, as well as unique scientific insightsinto visualization and applications of cell and molecular biology. With the 10thEdition, the authors guide students to make connections throughout cellbiology, and provide questions that encourage students to practice interpretingand analyzing data. Embedded features in Pearson eText add interactivity,walking students through key figures with narrated explanations. Personalizelearning with Mastering Biology with Pearson eText Mastering ® empowers youto personalize learning and reach every student. This flexible digital platformcombines trusted content with customizable features so you can teach yourcourse your way. And with digital tools and assessments, students become activeparticipants in their learning, leading to better results. PearsoneText is an easy-to-use digital textbook available within Mastering that letsstudents read, highlight, take notes, and review key vocabulary all in oneplace. If you’re not using Mastering, students can purchase Pearson eText ontheir own or you can assign it as a course to schedule readings, view studentusage analytics, and share your own notes with students. Cover Title Page Copyright About The Authors Detailed Contents Preface Acknowledgments Chapter 1. A Preview of Cell Biology 1.1 The Cell Theory: A Brief History Advances in Microscopy Allowed Detailed Studies of Cells The Cell Theory Applies to All Organisms 1.2 The Emergence of Modern Cell Biology The Cytological Strand Deals with Cellular Structure The Biochemical Strand Concerns the Chemistry of Biological Structure and Function The Genetic Strand Focuses on Information Flow 1.3 How Do We Know What We Know? Biological “Facts” May Turn Out to Be Incorrect Experiments Test Specific Hypotheses Model Organisms Play a Key Role in Modern Cell Biology Research Well-Designed Experiments Alter Only One Variable at a Time Summary of Key Points Problem Set Key Technique: Using Immunofluorescence to Identify Specific Cell Components Human Connections: The Immortal Cells of Henrietta Lacks Chapter 2. The Chemistry of the Cell 2.1 The Importance of Carbon Carbon-Containing Molecules Are Stable Carbon-Containing Molecules Are Diverse Carbon-Containing Molecules Can Form Stereoisomers 2.2 The Importance of Water Water Molecules Are Polar Water Molecules Are Cohesive Water Has a High Temperature-Stabilizing Capacity Water Is an Excellent Solvent 2.3 The Importance of Selectively Permeable Membranes A Membrane Is a Lipid Bilayer with Proteins Embedded in It Lipid Bilayers Are Selectively Permeable 2.4 The Importance of Synthesis by Polymerization Macromolecules Are Critical for Cellular Form and Function Cells Contain Three Different Kinds of Macromolecular Polymers Macromolecules Are Synthesized by Stepwise Polymerization of Monomers 2.5 The Importance of Self-Assembly Noncovalent Bonds and Interactions Are Important in the Folding of Macromolecules Many Proteins Spontaneously Fold into Their Biologically Functional State Molecular Chaperones Assist the Assembly of Some Proteins Self-Assembly Also Occurs in Other Cellular Structures The Tobacco Mosaic Virus Is a Case Study in Self-Assembly Self-Assembly Has Limits Hierarchical Assembly Provides Advantages for the Cell Summary of Key Points Problem Set Key Technique: Determining the Chemical Fingerprint of a Cell Using Mass Spectrometry Human Connections: Taking a Deeper Look: Magnetic Resonance Imaging (MRI) Chapter 3. The Macromolecules of the Cell 3.1 Proteins The Monomers Are Amino Acids The Polymers Are Polypeptides and Proteins Several Kinds of Bonds and Interactions Are Important in Protein Folding and Stability Protein Structure Depends on Amino Acid Sequence and Interactions 3.2 Nucleic Acids The Monomers Are Nucleotides The Polymers Are DNA and RNA A DNA Molecule Is a Double-Stranded Helix 3.3 Polysaccharides The Monomers Are Monosaccharides The Polymers Are Storage and Structural Polysaccharides Polysaccharide Structure Depends on the Kinds of Glycosidic Bonds Involved 3.4 Lipids Fatty Acids Are the Building Blocks of Several Classes of Lipids Triacylglycerols Are Storage Lipids Phospholipids Are Important in Membrane Structure Glycolipids Are Specialized Membrane Components Steroids Are Lipids with a Variety of Functions Terpenes Are Formed from Isoprene Summary of Key Points Problem Set Human Connections: Aggregated Proteins and Alzheimer’s Key Technique: Using X-Ray Crystallography to Determine Protein Structure Chapter 4. Cells and Organelles 4.1 The Origins of the First Cells Simple Organic Molecules May Have Formed Abiotically in the Young Earth RNA May Have Been the First Informational Molecule Liposomes May Have Defined the First Primitive Protocells 4.2 Basic Properties of Cells The Three Domains of Life Are Bacteria, Archaea, and Eukaryotes There Are Several Limitations on Cell Size Bacteria, Archaea, and Eukaryotes Differ from Each Other in Many Ways 4.3 The Eukaryotic Cell in Overview: Structure and Function The Plasma Membrane Defines Cell Boundaries and Retains Contents The Nucleus Is the Information Center of the Eukaryotic Cell Mitochondria and Chloroplasts Provide Energy for the Cell The Endosymbiont Theory Proposes That Mitochondria and Chloroplasts Were Derived from Bacteria The Endomembrane System Synthesizes Proteins for a Variety of Cellular Destinations Other Organelles Also Have Specific Functions Ribosomes Synthesize Proteins in the Cytoplasm The Cytoskeleton Provides Structure to the Cytoplasm The Extracellular Matrix and Cell Walls Are Outside the Plasma Membrane 4.4 Viruses, Viroids, and Prions: Agents That Invade Cells A Virus Consists of a DNA or RNA Core Surrounded by a Protein Coat Viroids Are Small, Circular RNA Molecules That Can Cause Plant Diseases Prions Are Infectious Protein Molecules Summary of Key Points Problem Set Human Connections: When Cellular “Breakdown” Breaks Down Key Technique: Using Centrifugation to Isolate Organelles Chapter 5. Bioenergetics: The Flow of Energy in the Cell 5.1 The Importance of Energy Cells Need Energy to Perform Six Different Kinds of Work Organisms Obtain Energy Either from Sunlight or from the Oxidation of Chemical Compounds Energy Flows Through the Biosphere Continuously The Flow of Energy Through the Biosphere Is Accompanied by a Flow of Matter 5.2 Bioenergetics Understanding Energy Flow Requires Knowledge of Systems, Heat, and Work The First Law of Thermodynamics States That Energy Is Conserved The Second Law of Thermodynamics States That Reactions Have Directionality Entropy and Free Energy Are Two Means of Assessing Thermodynamic Spontaneity 5.3 Understanding ΔG and Keq The Equilibrium Constant Keq Is a Measure of Directionality ΔG Can Be Calculated Readily The Standard Free Energy Change Is ΔG Measured Under Standard Conditions Summing Up: The Meaning of ΔGʹ and ΔG°ʹ Free Energy Change: Sample Calculations Jumping Beans Provide a Useful Analogy for Bioenergetics Life Requires Steady-State Reactions That Move Toward Equilibrium Without Ever Getting There Summary of Key Points Problem Set Human Connections: The “Potential” of Food to Provide Energy Key Technique: Measuring How Molecules Bind to One Another Using Isothermal Titration Calorimetry Chapter 6. Enzymes: The Catalysts of Life 6.1 Activation Energy and the Metastable State Before a Chemical Reaction Can Occur, the Activation Energy Barrier Must Be Overcome The Metastable State Is a Result of the Activation Barrier Catalysts Overcome the Activation Energy Barrier 6.2 Enzymes as Biological Catalysts Most Enzymes Are Proteins Substrate Binding, Activation, and Catalysis Occur at the Active Site Ribozymes Are Catalytic RNA Molecules 6.3 Enzyme Kinetics Monkeys and Peanuts Provide a Useful Analogy for Understanding Enzyme Kinetics Most Enzymes Display Michaelis–Menten Kinetics What Is the Meaning of V max and Km? Why Are Km and Vmax Important to Cell Biologists? The Double-Reciprocal Plot Is a Useful Means of Visualizing Kinetic Data Enzyme Inhibitors Act Either Irreversibly or Reversibly 6.4 Enzyme Regulation Allosteric Enzymes Are Regulated by Molecules Other than Reactants and Products Allosteric Enzymes Exhibit Cooperative Interactions Between Subunits Enzymes Can Also Be Regulated by the Addition or Removal of Chemical Groups Summary of Key Points Problem Set Human Connections: Ace Inhibitors: Enzyme Activity as TheDifference Between Life and Death Key Technique: Determining Km and Vmax Using Enzyme Assays Chapter 7. Membranes: Their Structure, Function, and Chemistry 7.1 The Functions of Membranes Membranes Define Boundaries and Serve as Permeability Barriers Membranes Contain Specific Proteins and Therefore Have Specific Functions Membrane Proteins Regulate the Transport of Solutes Membrane Proteins Detect and Transmit Electrical and Chemical Signals Membrane Proteins Mediate Cell Adhesion and Cell-to-Cell Communication 7.2 Models of Membrane Structure: An Experimental Perspective Overton and Langmuir: Lipids Are Important Components of Membranes Gorter and Grendel: The Basis of Membrane Structure Is a Lipid Bilayer Davson and Danielli: Membranes Also Contain Proteins Robertson: All Membranes Share a Common Underlying Structure Further Research Revealed Major Shortcomings of the Davson–Danielli Model Singer and Nicolson: A Membrane Consists of a Mosaic of Proteins in a Fluid Lipid Bilayer Unwin and Henderson: Most Membrane Proteins Contain Transmembrane Segments 7.3 Membrane Lipids: The “Fluid” Part of the Model Membranes Contain Several Major Classes of Lipids Fatty Acids Are Essential to Membrane Structure and Function Thin-Layer Chromatography Is an Important Technique for Lipid Analysis Membrane Asymmetry: Most Lipids Are Distributed Unequally Between the Two Monolayers The Lipid Bilayer Is Fluid Most Organisms Can Regulate Membrane Fluidity Lipid Micro- or Nanodomains May Localize Molecules in Membranes 7.4 Membrane Proteins: The “Mosaic” Part of the Model The Membrane Consists of a Mosaic of Proteins: Evidence from Freeze-Fracture Microscopy Membranes Contain Integral, Peripheral, and Lipid-Anchored Proteins Membrane Proteins Can Be Isolated and Analyzed Determining the Three-Dimensional Structure of Membrane Proteins Is Becoming Easier Molecular Biology Has Contributed Greatly to Our Understanding of Membrane Proteins Membrane Proteins Have a Variety of Functions Membrane Proteins Are Oriented Asymmetrically Across the Lipid Bilayer Many Membrane Proteins and Lipids Are Glycosylated Membrane Proteins Vary in Their Mobility The Erythrocyte Membrane Contains an Interconnected Network of Membrane-Associated Proteins Summary of Key Points Problem Set Key Technique: Fluorescence Recovery After Photobleaching (FRAP) Human Connections: It’s All in the Family Chapter 8. Transport Across Membranes: Overcoming the Permeability Barrier 8.1 Cells and Transport Processes Solutes Cross Membranes by Simple Diffusion, Facilitated Diffusion, and Active Transport The Movement of a Solute Across a Membrane Is Determined by Its Concentration Gradient or Its Electrochemical Potential The Erythrocyte Plasma Membrane Provides Examples of Transport 8.2 Simple Diffusion: Unassisted Movement Down the Gradient Simple Diffusion Always Moves Solutes Toward Equilibrium Osmosis Is the Simple Diffusion of Water Across a Selectively Permeable Membrane Simple Diffusion Is Typically Limited to Small, Uncharged Molecules The Rate of Simple Diffusion Is Directly Proportional to the Concentration Gradient 8.3 Facilitated Diffusion: Protein-Mediated Movement Down the Gradient Carrier Proteins and Channel Proteins Facilitate Diffusion by Different Mechanisms Carrier Proteins Alternate Between Two Conformational States Carrier Proteins Are Analogous to Enzymes in Their Specificity and Kinetics Carrier Proteins Transport Either One or Two Solutes The Erythrocyte Glucose Transporter and Anion Exchange Protein Are Examples of Carrier Proteins Channel Proteins Facilitate Diffusion by Forming Hydrophilic Transmembrane Channels 8.4 Active Transport: Protein-Mediated Movement Up the Gradient The Coupling of Active Transport to an Energy Source May Be Direct or Indirect Direct Active Transport Depends on Four Types of Transport ATPases Indirect Active Transport Is Driven by Ion Gradients 8.5 Examples of Active Transport Direct Active Transport: The Na+/K+ Pump Maintains Electrochemical Ion Gradients Indirect Active Transport: Sodium Symport Drives the Uptake of Glucose The Bacteriorhodopsin Proton Pump Uses Light Energy to Transport Protons 8.6 The Energetics of Transport For Uncharged Solutes, the ΔG of Transport Depends Only on the Concentration Gradient For Charged Solutes, the ΔG of Transport Depends on the Electrochemical Potential Summary of Key Points Problem Set Key Technique: Expression of Heterologous Membrane Proteins in Frog Oocytes Human Connections: Membrane Transport, Cystic Fibrosis, and the Prospects for Gene Therapy Chapter 9. Chemotrophic Energy Metabolism: Glycolysis and Fermentation 9.1 Metabolic Pathways 9.2 ATP: The Primary Energy Molecule in Cells ATP Contains Two Energy-Rich Phosphoanhydride Bonds ATP Hydrolysis Is Exergonic Due to Several Factors ATP Is Extremely Important in Cellular Energy Metabolism 9.3 Chemotrophic Energy Metabolism Biological Oxidations Usually Involve the Removal of Both Electrons and Protons and Are Exergonic Coenzymes Such as NAD+ Serve as Electron Acceptors in Biological Oxidations Most Chemotrophs Meet Their Energy Needs by Oxidizing Organic Food Molecules Glucose Is One of the Most Important Oxidizable Substrates in Energy Metabolism The Oxidation of Glucose Is Highly Exergonic Glucose Catabolism Yields Much More Energy in the Presence of Oxygen Than in Its Absence Based on Their Need for Oxygen, Organisms Are Aerobic, Anaerobic, or Facultative 9.4 Glycolysis: ATP Generation Without the Involvement of Oxygen Glycolysis Generates ATP by Catabolizing Glucose to Pyruvate 9.5 Fermentation In the Absence of Oxygen, Pyruvate Undergoes Fermentation to Regenerate NAD+ Fermentation Taps Only a Fraction of the Substrate’s Free Energy but Conserves That Energy Efficiently as ATP Cancer Cells Ferment Glucose to Lactate Even in the Presence of Oxygen 9.6 Alternative Substrates for Glycolysis Other Sugars and Glycerol Are Also Catabolized by the Glycolytic Pathway Polysaccharides Are Cleaved to Form Sugar Phosphates That Also Enter the Glycolytic Pathway 9.7 Gluconeogenesis 9.8 The Regulation of Glycolysis and Gluconeogenesis Key Enzymes in the Glycolytic and Gluconeogenic Pathways Are Subject to Allosteric Regulation Fructose-2,6-Bisphosphate Is an Important Regulator of Glycolysis and Gluconeogenesis Glycolytic Enzymes May Have Functions Beyond Glycolysis Summary of Key Points Problem Set Key Technique: Using Isotopic Labeling to Determine the Fate of Atoms in a Metabolic Pathway Human Connections: What Happens to the Sugar? Chapter 10. Chemotrophic Energy Metabolism: Aerobic Respiration 10.1 Cellular Respiration: Maximizing ATP Yields Aerobic Respiration Yields Much More Energy than Fermentation Does Respiration Includes Glycolysis, Pyruvate Oxidation, the Citric Acid Cycle, Electron Transport, and ATP Synthesis 10.2 The Mitochondrion: Where the Action Takes Place Mitochondria Are Often Present Where the ATP Needs Are Greatest Mitochondria Can Adopt Complex Shapes and Vary in Number in Different Cell Types The Outer and Inner Membranes Define Two Separate Mitochondrial Compartments and Three Regions Many Mitochondrial Proteins Originate in the Cytosol Mitochondrial Functions Occur in or on Specific Membranes and Compartments In Bacteria, Respiratory Functions Are Localized to the Plasma Membrane and the Cytoplasm 10.3 The Citric Acid Cycle: Oxidation in the Round Pyruvate Is Converted to Acetyl Coenzyme A by Oxidative Decarboxylation The Citric Acid Cycle Begins with the Entry of Two Carbons from Acetyl CoA Two Oxidative Decarboxylations Then Form NADH and Release CO2 Direct Generation of GTP (or ATP) Occurs at One Step in the Citric Acid Cycle The Final Oxidative Reactions of the Citric Acid Cycle Generate FADH2 and NADH Summing Up: The Products of the Citric Acid Cycle Are CO2 , ATP, NADH, and FADH2 Several Citric Acid Cycle Enzymes Are Subject to Allosteric Regulation The Citric Acid Cycle Also Plays a Central Role in the Catabolism of Fats and Proteins The Citric Acid Cycle Serves as a Source of Precursors for Anabolic Pathways The Glyoxylate Cycle Converts Acetyl CoA to Carbohydrates in Plants 10.4 Electron Transport: Electron Flow from Coenzymes to Oxygen The Electron Transport Chain Conveys Electrons from Reduced Coenzymes to Oxygen The Electron Transport Chain Consists of Five Kinds of Carriers The Electron Carriers Function in a Sequence Determined by Their Reduction Potentials Most of the Carriers Are Organized into Four Large Respiratory Complexes The Respiratory Complexes Move Freely Within the Inner Membrane 10.5 The Electrochemical Proton Gradient: Key to Energy Coupling Electron Transport and ATP Synthesis Are Coupled Events Coenzyme Oxidation Pumps Enough Protons to Form Three ATP Moleculesper NADH and Two ATP Molecules per FADH2 The Chemiosmotic Model Is Affirmed by an Impressive Array of Evidence 10.6 ATP Synthesis: Putting It All Together F1 Particles Have ATP Synthase Activity Proton Translocation Through Fo Drives ATP Synthesis by F1 ATP Synthesis by FoF1 Involves Physical Rotation of the Gamma Subunit 10.7 Aerobic Respiration: Summing It All Up The Actual ATP Yield per Glucose during Aerobic Respiration Is Influencedby Several Factors Aerobic Respiration: A Remarkable Process Summary of Key Points Problem Set Key Technique: Visualizing Cellular Structures with Three-Dimensional Electron Microscopy Human Connections: A Diet Worth Dying For? Chapter 11. Phototrophic Energy Metabolism: Photosynthesis 11.1 An Overview of Photosynthesis The Energy Transduction Reactions Convert Solar Energy to Chemical Energy The Carbon Assimilation Reactions Fix Carbon by Reducing Carbon Dioxide The Chloroplast Is the Photosynthetic Organelle in Eukaryotic Cells Chloroplasts Are Composed of Three Membrane Systems 11.2 Photosynthetic Energy Transduction I: Light Harvesting Chlorophyll Is Life’s Primary Link to Sunlight Accessory Pigments Further Expand Access to Solar Energy Light-Gathering Molecules Are Organized into Photosystems and Light-Harvesting Complexes Oxygenic Phototrophs Have Two Types of Photosystems 11.3 Photosynthetic Energy Transduction II: NADPH Synthesis Photosystem II Transfers Electrons from Water to a Plastoquinone The Cytochrome b6/f Complex Transfers Electrons from a Plastoquinol to Plastocyanin Photosystem I Transfers Electrons from Plastocyanin to Ferredoxin Ferredoxin-NADP+ Reductase Catalyzes the Reduction of NADP+ 11.4 Photosynthetic Energy Transduction III: ATP Synthesis A Chloroplast ATP Synthase Couples Transport of Protons Across the Thylakoid Membrane to ATP Synthesis Cyclic Photophosphorylation Allows a Photosynthetic Cell to Balance NADPH and ATP Synthesis A Summary of the Complete Energy Transduction System Bacteria Use a Photosynthetic Reaction Center and Electron Transport System Similar to Those in Plants 11.5 Photosynthetic Carbon Assimilation I: The Calvin Cycle Carbon Dioxide Enters the Calvin Cycle by Carboxylation of Ribulose-1,5-Bisphosphate 3-Phosphoglycerate Is Reduced to Form Glyceraldehyde-3-Phosphate Regeneration of Ribulose-1,5-Bisphosphate Allows Continuous Carbon Assimilation The Complete Calvin Cycle and Its Relation to Photosynthetic Energy Transduction 11.6 Regulation of the Calvin Cycle The Calvin Cycle Is Highly Regulated to Ensure Maximum Efficiency Rubisco Activase Regulates Carbon Fixation by Rubisco 11.7 Photosynthetic Carbon Assimilation II: Carbohydrate Synthesis Glucose-1-Phosphate Is Synthesized from Triose Phosphates Biosynthesis of Sucrose Occurs in the Cytosol Biosynthesis of Starch Occurs in the Chloroplast Stroma Photosynthesis Also Produces Reduced Nitrogen and Sulfur Compounds 11.8 Rubisco’s Oxygenase Activity Decreases Photosynthetic Efficiency The Glycolate Pathway Returns Reduced Carbon from Phosphoglycolate to the Calvin Cycle C4 Plants Minimize Photorespiration by Confining Rubisco to CellsContaining High Concentrations of CO2 CAM Plants Minimize Photorespiration and Water Loss by Opening Their Stomata Only at Night Summary of Key Points Problem Set Key Technique: Determining Absorption and Action Spectra via Spectrophotometry Human Connections: How Do Plants Put On Sunscreen? Chapter 12. The Endomembrane System and Protein Sorting 12.1 The Endoplasmic Reticulum The Two Basic Kinds of Endoplasmic Reticulum Differ in Structure and Function Rough ER Is Involved in the Biosynthesis and Processing of Proteins Smooth ER Is Involved in Drug Detoxification, Carbohydrate Metabolism, Calcium Storage, and Steroid Biosynthesis The ER Plays a Central Role in the Biosynthesis of Membranes 12.2 The Golgi Apparatus The Golgi Apparatus Consists of a Series of Membrane-Bounded Cisternae Two Models Account for the Flow of Lipids and Proteins Through the Golgi Apparatus 12.3 Roles of the ER and Golgi Apparatus in Protein Processing Protein Folding and Quality Control Take Place Within the ER Initial Glycosylation Occurs in the ER Further Glycosylation Occurs in the Golgi Apparatus 12.4 Roles of the ER and Golgi Apparatus In Protein Trafficking Cotranslational Import Allows Some Polypeptides to Enter the ER as They Are Being Synthesized The Signal Recognition Particle (SRP) Attaches the Ribosome-mRNA-PolypeptideComplex to the ER Membrane Proteins Released into the ER Lumen Are Routed to the Golgi Apparatus, Secretory Vesicles, Lysosomes, or Back to the ER Stop-Transfer Sequences Mediate the Insertion of Integral Membrane Proteins Posttranslational Import Is an Alternative Mechanism for Import into the ER Lumen 12.5 Exocytosis and Endocytosis: Transporting Material Across the Plasma Membrane Secretory Pathways Transport Molecules to the Exterior of the Cell Exocytosis Releases Intracellular Molecules Outside the Cell Endocytosis Imports Extracellular Molecules by Forming Vesicles from the Plasma Membrane 12.6 Coated Vesicles in Cellular Transport Processes Clathrin-Coated Vesicles Are Surrounded by Lattices Composed of Clathrin and Adaptor Protein The Assembly of Clathrin Coats Drives the Formation of Vesicles from the Plasma Membrane and TGN COPI- and COPII-Coated Vesicles Travel Between the ER and Golgi Apparatus Cisternae SNARE Proteins Mediate Fusion Between Vesicles and Target Membranes 12.7 Lysosomes and Cellular Digestion Lysosomes Isolate Digestive Enzymes from the Rest of the Cell Lysosomes Develop from Endosomes Lysosomal Enzymes Are Important for Several Different Digestive Processes Lysosomal Storage Diseases Are Usually Characterized by the Accumulation of Indigestible Material The Plant Vacuole: A Multifunctional Digestive Organelle 12.8 Peroxisomes Most Peroxisomal Functions Are Linked to Hydrogen Peroxide Metabolism Plant Cells Contain Types of Peroxisomes Not Found in Animal Cells Peroxisome Biogenesis Can Occur by Division of Preexisting Peroxisomes or by Vesicle Fusion Summary of Key Points Problem Set Key Technique: Visualizing Vesicles at the Cell Surface Using Total Internal Reflection (TIRF) Microscopy Human Connections: A Bad Case of the Munchies? (Autophagy In Inflammatory Bowel Disease) Chapter 13. Cytoskeletal Systems 13.1 Major Structural Elements of the Cytoskeleton Eukaryotes Have Three Basic Types of Cytoskeletal Elements Bacteria Have Cytoskeletal Systems That Are Structurally Similar to Those in Eukaryotes The Cytoskeleton Is Dynamically Assembled and Disassembled 13.2 Microtubules Two Types of Microtubules Are Responsible for Many Functions in the Cell Tubulin Heterodimers Are the Protein Building Blocks of Microtubules Microtubules Can Form as Singlets, Doublets, or Triplets Microtubules Form by the Addition of Tubulin Dimers at Their Ends Addition of Tubulin Dimers Occurs More Quickly at the Plus Ends of Microtubules Drugs Can Affect the Assembly and Stability of Microtubules GTP Hydrolysis Contributes to the Dynamic Instability of Microtubules Microtubules Originate from Microtubule-Organizing Centers Within the Cell MTOCs Organize and Polarize Microtubules Within Cells Microtubule Stability Is Tightly Regulated in Cells by a Variety of Microtubule-Binding Proteins 13.3 Microfilaments Actin Is the Protein Building Block of Microfilaments Different Types of Actin Are Found in Cells G-Actin Monomers Polymerize into F-Actin Microfilaments Specific Drugs Affect Polymerization of Microfilaments Cells Can Dynamically Assemble Actin into a Variety of Structures Actin-Binding Proteins Regulate the Polymerization, Length, and Organization of Microfilaments Proteins That Link Actin to Membranes Phospholipids and Rho Family GTPases Regulate Where and When Actin-Based Structures Assemble 13.4 Intermediate Filaments Intermediate Filament Proteins Are Tissue Specific Intermediate Filaments Assemble from Fibrous Subunits Intermediate Filaments Confer Mechanical Strength on Tissues The Cytoskeleton Is a Mechanically Integrated Structure Summary of Key Points Problem Set Key Technique: Studying the Dynamic Cytoskeleton Human Connections: When Actin Kills Chapter 14. Cellular Movement: Motility and Contractility 14.1 Microtubule-Based Movement Inside Cells: Kinesins and Dyneins Motor Proteins Move Cargoes Along MTs During Axonal Transport Classic Kinesins Move Toward the Plus Ends of Microtubules Kinesins Are a Large Family of Proteins Dyneins Are Found in Axonemes and the Cytosol Microtubule Motors Direct Vesicle Transport and Shape the Endomem-brane System 14.2 Microtubule-Based Cell Motility: Cilia And Flagella Cilia and Flagella Are Common Motile Appendages of Eukaryotic Cells Cilia and Flagella Consist of an Axoneme Connected to a Basal Body Doublet Sliding Within the Axoneme Causes Cilia and Flagella to Bend 14.3 Microfilament-Based Movement Inside Cells: Myosins Myosins Are a Large Family of Actin-Based Motors with Diverse Roles in Cell Motility Many Myosins Move Along Actin Filaments in Short Steps 14.4 Microfilament-Based Motility: Muscle Cells In Action Skeletal Muscle Cells Contain Thin and Thick Filaments Sarcomeres Contain Ordered Arrays of Actin, Myosin, and Accessory Proteins The Sliding-Filament Model Explains Muscle Contraction Cross-Bridges Hold Filaments Together, and ATP Powers Their Movement The Regulation of Muscle Contraction Depends on Calcium The Coordinated Contraction of Cardiac Muscle Cells Involves Electrical Coupling Smooth Muscle Is More Similar to Nonmuscle Cells than to Skeletal Muscle 14.5 Microfilament-Based Motility In Nonmuscle Cells Cell Migration via Lamellipodia Involves Cycles of Protrusion, Attachment, Translocation, and Detachment Chemotaxis Is a Directional Movement in Response to a Graded Chemical Stimulus Amoeboid Movement Involves Cycles of Gelation and Solation of Actin Actin-Based Motors Move Components Within the Cytosol of Some Cells Summary of Key Points Problem Set Key Technique: Watching Motors Too Small to See Human Connections: Dyneins Help Us Tell Left From Right Chapter 15. Beyond the Cell: Cell Adhesions, Cell Junctions, and Extracellular Structures 15.1 Cell-Cell Junctions Adhesive Junctions Link Adjoining Cells Transient Cell-Cell Adhesions Are Important for Many Cellular Events Tight Junctions Prevent the Movement of Molecules Across Cell Layers Gap Junctions Allow Direct Electrical and Chemical Communication Between Cells 15.2 The Extracellular Matrix of Animal Cells Collagens Are Responsible for the Strength of the Extracellular Matrix Elastins Impart Elasticity and Flexibility to the Extracellular Matrix Collagen and Elastin Fibers Are Embedded in a Matrix of Proteoglycans Free Hyaluronate Lubricates Joints and Facilitates Cell Migration Adhesive Glycoproteins Anchor Cells to the Extracellular Matrix Fibronectins Bind Cells to the ECM and Foster Cellular Movement Laminins Bind Cells to the Basal Lamina Integrins Are Cell Surface Receptors That Bind ECM Components The Dystrophin/Dystroglycan Complex Stabilizes Attachments of Muscle Cells to the ECM 15.3 The Plant Cell Surface Cell Walls Provide a Structural Framework and Serve as a Permeability Barrier The Plant Cell Wall Is a Network of Cellulose Microfibrils, Polysaccharides, and Glycoproteins Cell Walls Are Synthesized in Several Discrete Stages Plasmodesmata Permit Direct Cell-Cell Communication Through the Cell Wall Summary of Key Points Problem Set Human Connections: The Costly Effects of Weak Adhesion Key Technique: Building an ECM from Scratch Chapter 16. The Structural Basis of Cellular Information: DNA, Chromosomes, and the Nucleus 16.1 Chemical Nature of the Genetic Material The Discovery of DNA Led to Conflicting Proposals Concerning the Chemical Nature of Genes Avery, MacLeod, and McCarty Showed That DNA Is the Genetic Material of Bacteria Hershey and Chase Showed That DNA Is the Genetic Material of Viruses RNA Is the Genetic Material in Some Viruses 16.2 DNA Structure Chargaff ’s Rules Reveal That A = T and G = C Watson and Crick Discovered That DNA Is a Double Helix DNA Can Be Interconverted Between Relaxed and Supercoiled Forms The Two Strands of a DNA Double Helix Can Be Denatured and Renatured 16.3 DNA Packaging Bacteria Package DNA in Bacterial Chromosomes and Plasmids Eukaryotes Package DNA in Chromatin and Chromosomes Nucleosomes Are the Basic Unit of Chromatin Structure A Histone Octamer Forms the Nucleosome Core Nucleosomes Are Packed Together to Form Chromatin Fibers and Chromosomes Changes in Histones and Chromatin Remodeling Proteins Can Alter Chromatin Packing Chromosomal DNA Contains Euchromatin and Heterochromatin Some Heterochromatin Plays a Structural Role in Chromosomes Chromosomes Can Be Identified by Unique Banding Patterns Eukaryotic Chromosomes Contain Large Amounts of Repeated DNA Sequences Eukaryotes Package Some of Their DNA in Mitochondria and Chloroplasts 16.4 The Nucleus A Double-Membrane Nuclear Envelope Surrounds the Nucleus Molecules Enter and Exit the Nucleus Through Nuclear Pores The Nucleus Is Mechanically Integrated with the Rest of the Cell Chromatin Is Located Within the Nucleus in a Nonrandom Fashion The Nucleolus Is Involved in Ribosome Formation Summary of Key Points Problem Set Key Technique: FISHing for Specific Sequences Human Connections: Lamins and Premature Aging Chapter 17. DNA Replication, Repair, and Recombination 17.1 DNA Replication DNA Synthesis Occurs During S Phase DNA Replication Is Semiconservative DNA Replication Is Usually Bidirectional Replication Initiates at Specialized DNA Elements DNA Polymerases Catalyze the Elongation of DNA Chains DNA Is Synthesized as Discontinuous Segments That Are Joined Together by DNA Ligase In Bacteria, Proofreading Is Performed by the 3'→5' Exonuclease Activity of DNA Polymerase RNA Primers Initiate DNA Replication The DNA Double Helix Must Be Locally Unwound During Replication DNA Unwinding and DNA Synthesis Are Coordinated on Both Strands via This textbook is intended as a comprehensive introduction to cellular and molecular biology for students preparing for careers in biology, medicine and related fields. Its goal is to present essential principles, processes, and methodology. Forcourses in cell biology. Connectingfundamental concepts across the world of the cellKnown for its strong biochemistry coverage and clear, easy-to-followexplanations and figures, Beckers World of the Cell provides abeautifully illustrated, up-to-date introduction to cell biology concepts,processes, and applications. Informed by years of classroom experience in thecell biology course, the text features accessible and authoritativedescriptions of all major principles, as well as unique scientific insightsinto visualization and applications of cell and molecular biology. With the 10thEdition, the authors guide students to make connections throughout cellbiology, and provide questions that encourage students to practice interpretingand analyzing data. Embedded features in Pearson eText add interactivity,walking students through key figures with narrated explanations. Personalizelearning with Mastering Biology with Pearson eTextMastering empowers youto personalize learning and reach every student. This flexible digital platformcombines trusted content with customizable features so you can teach yourcourse your way. And with digital tools and assessments, students become activeparticipants in their learning, leading to better results. PearsoneText is an easy-to-use digital textbook available within Mastering that letsstudents read, highlight, take notes, and review key vocabulary all in oneplace. If youre not using Mastering, students can purchase Pearson eText ontheir own or you can assign it as a course to schedule readings, view studentusage analytics, and share your own notes with students For courses incell biology. Connecting fundamentalconcepts across the world of the cell Known for its strong biochemistry coverage and clear, easy-to-followexplanations and figures, Becker's World of the Cell provides abeautifully illustrated, up-to-date introduction to cell biology concepts,processes, and applications. Informed by years of classroom experience in thecell biology course, the text features accessible and authoritativedescriptions of all major principles, as well as unique scientific insightsinto visualization and applications of cell and molecular biology. With the 10thEdition, the authors guide students to make connections throughout cell biologyand provide questions that encourage students to practice interpreting andanalyzing data. Embedded features in Pearson eText add interactivity, walkingstudents through key figures with narrated explanations. Personalizelearning with Mastering Biology with Pearson eText Mastering® empowers you topersonalize learning and reach every student. This flexible digital platformcombines trusted content with customizable features so you can teach yourcourse your way. And with digital tools and assessments, students become activeparticipants in their learning, leading to better results. Pearson eText is an easy-to-usedigital textbook available within Mastering that lets students read, highlight,take notes, and review key vocabulary all in one place. If you're not usingMastering, students can purchase Pearson eText on their own or you can assignit as a course to schedule readings, view student usage analytics, and shareyour own notes with students.