- About this Book
关于这本书- Cover Page
封面 - Halftitle Page
半页标题页 - Title Page
标题页 - Copyright
版权 - Dedication
奉献 - About the Authors
关于作者 - A Note on the Nature of Science
关于科学本质的说明 - Overview of key features
概述关键特征 - Tools and Resources to Support Teaching
支持教学的工具和资源 - Acknowledgments
致谢 - Contents in Brief
目录简述 - Contents
目录
- Chapter 1 The Foundations of Biochemistry
第 1 章 生物化学基础- 1.1 Cellular Foundations
- Cells Are the Structural and Functional Units of All Living Organisms
- Cellular Dimensions Are Limited by Diffusion
- Organisms Belong to Three Distinct Domains of Life
- Organisms Differ Widely in Their Sources of Energy and Biosynthetic Precursors
- Bacterial and Archaeal Cells Share Common Features but Differ in Important Ways
- Eukaryotic Cells Have a Variety of Membranous Organelles, Which Can Be Isolated for Study
- The Cytoplasm Is Organized by the Cytoskeleton and Is Highly Dynamic
- Cells Build Supramolecular Structures
- In Vitro Studies May Overlook Important Interactions among Molecules
- 1.2 Chemical Foundations
- Biomolecules Are Compounds of Carbon with a Variety of Functional Groups
- Cells Contain a Universal Set of Small Molecules
- Macromolecules Are the Major Constituents of Cells
- Three-Dimensional Structure Is Described by Configuration and Conformation
- Interactions between Biomolecules Are Stereospecific
- 1.3 Physical Foundations
- Living Organisms Exist in a Dynamic Steady State, Never at Equilibrium with Their Surroundings
- Organisms Transform Energy and Matter from Their Surroundings
- Creating and Maintaining Order Requires Work and Energy
- Energy Coupling Links Reactions in Biology
- K[eq] and ΔG° Are Measures of a Reaction’s Tendency to Proceed Spontaneously
- Enzymes Promote Sequences of Chemical Reactions
- Metabolism Is Regulated to Achieve Balance and Economy
- 1.4 Genetic Foundations
- Genetic Continuity Is Vested in Single DNA Molecules
- The Structure of DNA Allows Its Replication and Repair with Near-Perfect Fidelity
- The Linear Sequence in DNA Encodes Proteins with Three-Dimensional Structures
- 1.5 Evolutionary Foundations
- Changes in the Hereditary Instructions Allow Evolution
- Biomolecules First Arose by Chemical Evolution
- RNA or Related Precursors May Have Been the First Genes and Catalysts
- Biological Evolution Began More Than Three and a Half Billion Years Ago
- The First Cell Probably Used Inorganic Fuels
- Eukaryotic Cells Evolved from Simpler Precursors in Several Stages
- Molecular Anatomy Reveals Evolutionary Relationships
- Functional Genomics Shows the Allocations of Genes to Specific Cellular Processes
- Genomic Comparisons Have Increasing Importance in Medicine
- Chapter Review
- Key Terms
- Problems
- Part I Structure and Catalysis
第 I 部分 结构与催化作用- Chapter 2 Water, The Solvent of Life
- 2.1 Weak Interactions in Aqueous Systems
- Hydrogen Bonding Gives Water Its Unusual Properties
- Water Forms Hydrogen Bonds with Polar Solutes
- Water Interacts Electrostatically with Charged Solutes
- Nonpolar Gases Are Poorly Soluble in Water
- Nonpolar Compounds Force Energetically Unfavorable Changes in the Structure of Water
- van der Waals Interactions Are Weak Interatomic Attractions
- Weak Interactions Are Crucial to Macromolecular Structure and Function
- Concentrated Solutes Produce Osmotic Pressure
- 2.2 Ionization of Water, Weak Acids, and Weak Bases
- Pure Water Is Slightly Ionized
- The Ionization of Water Is Expressed by an Equilibrium Constant
- The pH Scale Designates the H[+] and H[−] Concentrations
- Weak Acids and Bases Have Characteristic Acid Dissociation Constants
- Titration Curves Reveal the p[Ka] of Weak Acids
- 2.3 Buffering against pH Changes in Biological Systems
- Buffers Are Mixtures of Weak Acids and Their Conjugate Bases
- The Henderson-Hasselbalch Equation Relates pH, p[Ka], and Buffer Concentration
- Weak Acids or Bases Buffer Cells and Tissues against pH Changes
- Untreated Diabetes Produces Life-Threatening Acidosis
- Chapter Review
- Key Terms
- Problems
- Chapter 3 Amino Acids, Peptides, and Proteins
- 3.1 Amino Acids
- Amino Acids Share Common Structural Features
- The Amino Acid Residues in Proteins Are L Stereoisomers
- Amino Acids Can Be Classified by R Group
- Uncommon Amino Acids Also Have Important Functions
- Amino Acids Can Act as Acids and Bases
- Amino Acids Differ in Their Acid-Base Properties
- 3.2 Peptides and Proteins
- Peptides Are Chains of Amino Acids
- Peptides Can Be Distinguished by Their Ionization Behavior
- Biologically Active Peptides and Polypeptides Occur in a Vast Range of Sizes and Compositions
- Some Proteins Contain Chemical Groups Other Than Amino Acids
- 3.3 Working with Proteins
- Proteins Can Be Separated and Purified
- Proteins Can Be Separated and Characterized by Electrophoresis
- Unseparated Proteins Are Detected and Quantified Based on Their Functions
- 3.4 The Structure of Proteins: Primary Structure
- The Function of a Protein Depends on Its Amino Acid Sequence
- Protein Structure Is Studied Using Methods That Exploit Protein Chemistry
- Mass Spectrometry Provides Information on Molecular Mass, Amino Acid Sequence, and Entire Proteomes
- Small Peptides and Proteins Can Be Chemically Synthesized
- Amino Acid Sequences Provide Important Biochemical Information
- Protein Sequences Help Elucidate the History of Life on Earth
- Chapter Review
- Key Terms
- Problems
- Chapter 4 The Three-Dimensional Structure of Proteins
- 4.1 Overview of Protein Structure
- A Protein’s Conformation Is Stabilized Largely by Weak Interactions
- Packing of Hydrophobic Amino Acids Away from Water Favors Protein Folding
- Polar Groups Contribute Hydrogen Bonds and Ion Pairs to Protein Folding
- Individual van der Waals Interactions Are Weak but Combine to Promote Folding
- The Peptide Bond Is Rigid and Planar
- 4.2 Protein Secondary Structure
- The α Helix Is a Common Protein Secondary Structure
- Amino Acid Sequence Affects Stability of the α Helix
- The β Conformation Organizes Polypeptide Chains into Sheets
- β Turns Are Common in Proteins
- Common Secondary Structures Have Characteristic Dihedral Angles
- Common Secondary Structures Can Be Assessed by Circular Dichroism
- 4.3 Protein Tertiary and Quaternary Structures
- Fibrous Proteins Are Adapted for a Structural Function
- Structural Diversity Reflects Functional Diversity in Globular Proteins
- Myoglobin Provided Early Clues about the Complexity of Globular Protein Structure
- Globular Proteins Have a Variety of Tertiary Structures
- Some Proteins or Protein Segments Are Intrinsically Disordered
- Protein Motifs Are the Basis for Protein Structural Classification
- Protein Quaternary Structures Range from Simple Dimers to Large Complexes
- 4.4 Protein Denaturation and Folding
- Loss of Protein Structure Results in Loss of Function
- Amino Acid Sequence Determines Tertiary Structure
- Polypeptides Fold Rapidly by a Stepwise Process
- Some Proteins Undergo Assisted Folding
- Defects in Protein Folding Are the Molecular Basis for Many Human Genetic Disorders
- 4.5 Determination of Protein and Biomolecular Structures
- X-ray Diffraction Produces Electron Density Maps from Protein Crystals
- Distances between Protein Atoms Can Be Measured by Nuclear Magnetic Resonance
- Thousands of Individual Molecules Are Used to Determine Structures by Cryo-Electron Microscopy
- Chapter Review
- Key Terms
- Problems
- Chapter 5 Protein Function
- 5.1 Reversible Binding of a Protein to a Ligand: Oxygen-Binding Proteins
- Oxygen Can Bind to a Heme Prosthetic Group
- Globins Are a Family of Oxygen-Binding Proteins
- Myoglobin Has a Single Binding Site for Oxygen
- Protein-Ligand Interactions Can Be Described Quantitatively
- Protein Structure Affects How Ligands Bind
- Hemoglobin Transports Oxygen in Blood
- Hemoglobin Subunits Are Structurally Similar to Myoglobin
- Hemoglobin Undergoes a Structural Change on Binding Oxygen
- Hemoglobin Binds Oxygen Cooperatively
- Cooperative Ligand Binding Can Be Described Quantitatively
- Two Models Suggest Mechanisms for Cooperative Binding
- Hemoglobin Also Transports H[+] and CO[2]
- Oxygen Binding to Hemoglobin Is Regulated by 2,3-Bisphosphoglycerate
- Sickle Cell Anemia Is a Molecular Disease of Hemoglobin
- 5.2 Complementary Interactions between Proteins and Ligands: The Immune System and Immunoglobulins
- The Immune Response Includes a Specialized Array of Cells and Proteins
- Antibodies Have Two Identical Antigen-Binding Sites
- Antibodies Bind Tightly and Specifically to Antigen
- The Antibody-Antigen Interaction Is the Basis for a Variety of Important Analytical Procedures
- 5.3 Protein Interactions Modulated by Chemical Energy: Actin, Myosin, and Molecular Motors
- The Major Proteins of Muscle Are Myosin and Actin
- Additional Proteins Organize the Thin and Thick Filaments into Ordered Structures
- Myosin Thick Filaments Slide along Actin Thin Filaments
- Chapter Review
- Key Terms
- Problems
- Chapter 6 Enzymes
- 6.1 An Introduction to Enzymes
- Most Enzymes Are Proteins
- Enzymes Are Classified by the Reactions They Catalyze
- 6.2 How Enzymes Work
- Enzymes Affect Reaction Rates, Not Equilibria
- Reaction Rates and Equilibria Have Precise Thermodynamic Definitions
- A Few Principles Explain the Catalytic Power and Specificity of Enzymes
- Noncovalent Interactions between Enzyme and Substrate Are Optimized in the Transition State
- Covalent Interactions and Metal Ions Contribute to Catalysis
- 6.3 Enzyme Kinetics as an Approach to Understanding Mechanism
- Substrate Concentration Affects the Rate of Enzyme-Catalyzed Reactions
- The Relationship between Substrate Concentration and Reaction Rate Can Be Expressed with the Michaelis-Menten Equation
- Michaelis-Menten Kinetics Can Be Analyzed Quantitatively
- Kinetic Parameters Are Used to Compare Enzyme Activities
- Many Enzymes Catalyze Reactions with Two or More Substrates
- Enzyme Activity Depends on pH
- Pre–Steady State Kinetics Can Provide Evidence for Specific Reaction Steps
- Enzymes Are Subject to Reversible or Irreversible Inhibition
- 6.4 Examples of Enzymatic Reactions
- The Chymotrypsin Mechanism Involves Acylation and Deacylation of a Ser Residue
- An Understanding of Protease Mechanisms Leads to New Treatments for HIV Infection
- Hexokinase Undergoes Induced Fit on Substrate Binding
- The Enolase Reaction Mechanism Requires Metal Ions
- An Understanding of Enzyme Mechanism Produces Useful Antibiotics
- 6.5 Regulatory Enzymes
- Allosteric Enzymes Undergo Conformational Changes in Response to Modulator Binding
- The Kinetic Properties of Allosteric Enzymes Diverge from Michaelis-Menten Behavior
- Some Enzymes Are Regulated by Reversible Covalent Modification
- Phosphoryl Groups Affect the Structure and Catalytic Activity of Enzymes
- Multiple Phosphorylations Allow Exquisite Regulatory Control
- Some Enzymes and Other Proteins Are Regulated by Proteolytic Cleavage of an Enzyme Precursor
- A Cascade of Proteolytically Activated Zymogens Leads to Blood Coagulation
- Some Regulatory Enzymes Use Several Regulatory Mechanisms
- Chapter Review
- Key Terms
- Problems
- Chapter 7 Carbohydrates and Glycobiology
- 7.1 Monosaccharides and Disaccharides
- The Two Families of Monosaccharides Are Aldoses and Ketoses
- Monosaccharides Have Asymmetric Centers
- The Common Monosaccharides Have Cyclic Structures
- Organisms Contain a Variety of Hexose Derivatives
- Sugars That Are, or Can Form, Aldehydes Are Reducing Sugars
- 7.2 Polysaccharides
- Some Homopolysaccharides Are Storage Forms of Fuel
- Some Homopolysaccharides Serve Structural Roles
- Steric Factors and Hydrogen Bonding Influence Homopolysaccharide Folding
- Peptidoglycan Reinforces the Bacterial Cell Wall
- Glycosaminoglycans Are Heteropolysaccharides of the Extracellular Matrix
- 7.3 Glycoconjugates: Proteoglycans, Glycoproteins, and Glycolipids
- Proteoglycans Are Glycosaminoglycan-Containing Macromolecules of the Cell Surface and Extracellular Matrix
- Glycoproteins Have Covalently Attached Oligosaccharides
- Glycolipids and Lipopolysaccharides Are Membrane Components
- 7.4 Carbohydrates as Informational Molecules: The Sugar Code
- Oligosaccharide Structures Are Information-Dense
- Lectins Are Proteins That Read the Sugar Code and Mediate Many Biological Processes
- Lectin-Carbohydrate Interactions Are Highly Specific and Often Multivalent
- 7.5 Working with Carbohydrates
- Chapter Review
- Key Terms
- Problems
- Chapter 8 Nucleotides and Nucleic Acids
- 8.1 Some Basic Definitions and Conventions
- Nucleotides and Nucleic Acids Have Characteristic Bases and Pentoses
- Phosphodiester Bonds Link Successive Nucleotides in Nucleic Acids
- The Properties of Nucleotide Bases Affect the Three-Dimensional Structure of Nucleic Acids
- 8.2 Nucleic Acid Structure
- DNA Is a Double Helix That Stores Genetic Information
- DNA Can Occur in Different Three-Dimensional Forms
- Certain DNA Sequences Adopt Unusual Structures
- Messenger RNAs Code for Polypeptide Chains
- Many RNAs Have More Complex Three-Dimensional Structures
- 8.3 Nucleic Acid Chemistry
- Double-Helical DNA and RNA Can Be Denatured
- Nucleotides and Nucleic Acids Undergo Nonenzymatic Transformations
- Some Bases of DNA Are Methylated
- The Chemical Synthesis of DNA Has Been Automated
- Gene Sequences Can Be Amplified with the Polymerase Chain Reaction
- The Sequences of Long DNA Strands Can Be Determined
- DNA Sequencing Technologies Are Advancing Rapidly
- 8.4 Other Functions of Nucleotides
- Nucleotides Carry Chemical Energy in Cells
- Adenine Nucleotides Are Components of Many Enzyme Cofactors
- Some Nucleotides Are Regulatory Molecules
- Adenine Nucleotides Also Serve as Signals
- Chapter Review
- Key Terms
- Problems
- Chapter 9 DNA-Based Information Technologies
- 9.1 Studying Genes and Their Products
- Genes Can Be Isolated by DNA Cloning
- Restriction Endonucleases and DNA Ligases Yield Recombinant DNA
- Cloning Vectors Allow Amplification of Inserted DNA Segments
- Cloned Genes Can Be Expressed to Amplify Protein Production
- Many Different Systems Are Used to Express Recombinant Proteins
- Alteration of Cloned Genes Produces Altered Proteins
- Terminal Tags Provide Handles for Affinity Purification
- The Polymerase Chain Reaction Offers Many Options for Cloning Experiments
- DNA Libraries Are Specialized Catalogs of Genetic Information
- 9.2 Exploring Protein Function on the Scale of Cells or Whole Organisms
- Sequence or Structural Relationships Can Suggest Protein Function
- When and Where a Protein Is Present in a Cell Can Suggest Protein Function
- Knowing What a Protein Interacts with Can Suggest Its Function
- The Effect of Deleting or Altering a Protein Can Suggest Its Function
- Many Proteins Are Still Undiscovered
- 9.3 Genomics and the Human Story
- The Human Genome Contains Many Types of Sequences
- Genome Sequencing Informs Us about Our Humanity
- Genome Comparisons Help Locate Genes Involved in Disease
- Genome Sequences Inform Us about Our Past and Provide Opportunities for the Future
- Chapter Review
- Key Terms
- Problems
- Chapter 10 Lipids
- 10.1 Storage Lipids
- Fatty Acids Are Hydrocarbon Derivatives
- Triacylglycerols Are Fatty Acid Esters of Glycerol
- Triacylglycerols Provide Stored Energy and Insulation
- Partial Hydrogenation of Cooking Oils Improves Their Stability but Creates Fatty Acids with Harmful Health Effects
- Waxes Serve as Energy Stores and Water Repellents
- 10.2 Structural Lipids in Membranes
- Glycerophospholipids Are Derivatives of Phosphatidic Acid
- Some Glycerophospholipids Have Ether-Linked Fatty Acids
- Galactolipids of Plants and Ether-Linked Lipids of Archaea Are Environmental Adaptations
- Sphingolipids Are Derivatives of Sphingosine
- Sphingolipids at Cell Surfaces Are Sites of Biological Recognition
- Phospholipids and Sphingolipids Are Degraded in Lysosomes
- Sterols Have Four Fused Carbon Rings
- 10.3 Lipids as Signals, Cofactors, and Pigments
- Phosphatidylinositols and Sphingosine Derivatives Act as Intracellular Signals
- Eicosanoids Carry Messages to Nearby Cells
- Steroid Hormones Carry Messages between Tissues
- Vascular Plants Produce Thousands of Volatile Signals
- Vitamins A and D Are Hormone Precursors
- Vitamins E and K and the Lipid Quinones Are Oxidation-Reduction Cofactors
- Dolichols Activate Sugar Precursors for Biosynthesis
- Many Natural Pigments Are Lipidic Conjugated Dienes
- Polyketides Are Natural Products with Potent Biological Activities
- 10.4 Working with Lipids
- Lipid Extraction Requires Organic Solvents
- Adsorption Chromatography Separates Lipids of Different Polarity
- Gas Chromatography Resolves Mixtures of Volatile Lipid Derivatives
- Specific Hydrolysis Aids in Determination of Lipid Structure
- Mass Spectrometry Reveals Complete Lipid Structure
- Lipidomics Seeks to Catalog All Lipids and Their Functions
- Chapter Review
- Key Terms
- Problems
- Chapter 11 Biological Membranes and Transport
- 11.1 The Composition and Architecture of Membranes
- The Lipid Bilayer Is Stable in Water
- Bilayer Architecture Underlies the Structure and Function of Biological Membranes
- The Endomembrane System Is Dynamic and Functionally Differentiated
- Membrane Proteins Are Receptors, Transporters, and Enzymes
- Membrane Proteins Differ in the Nature of Their Association with the Membrane Bilayer
- The Topology of an Integral Membrane Protein Can Often Be Predicted from Its Sequence
- Covalently Attached Lipids Anchor or Direct Some Membrane Proteins
- 11.2 Membrane Dynamics
- Acyl Groups in the Bilayer Interior Are Ordered to Varying Degrees
- Transbilayer Movement of Lipids Requires Catalysis
- Lipids and Proteins Diffuse Laterally in the Bilayer
- Sphingolipids and Cholesterol Cluster Together in Membrane Rafts
- Membrane Curvature and Fusion Are Central to Many Biological Processes
- Integral Proteins of the Plasma Membrane Are Involved in Surface Adhesion, Signaling, and Other Cellular Processes
- 11.3 Solute Transport across Membranes
- Transport May Be Passive or Active
- Transporters and Ion Channels Share Some Structural Properties but Have Different Mechanisms
- The Glucose Transporter of Erythrocytes Mediates Passive Transport
- The Chloride-Bicarbonate Exchanger Catalyzes Electroneutral Cotransport of Anions across the Plasma Membrane
- Active Transport Results in Solute Movement against a Concentration or Electrochemical Gradient
- P-Type ATPases Undergo Phosphorylation during Their Catalytic Cycles
- V-Type and F-Type ATPases Are ATP-Driven Proton Pumps
- ABC Transporters Use ATP to Drive the Active Transport of a Wide Variety of Substrates
- Ion Gradients Provide the Energy for Secondary Active Transport
- Aquaporins Form Hydrophilic Transmembrane Channels for the Passage of Water
- Ion-Selective Channels Allow Rapid Movement of Ions across Membranes
- The Structure of a K[+] Channel Reveals the Basis for Its Specificity
- Chapter Review
- Key Terms
- Problems
- Chapter 12 Biochemical Signaling
- 12.1 General Features of Signal Transduction
- Signal-Transducing Systems Share Common Features
- The General Process of Signal Transduction in Animals Is Universal
- 12.2 G Protein–Coupled Receptors and Second Messengers
- The β-Adrenergic Receptor System Acts through the Second Messenger cAMP
- Cyclic AMP Activates Protein Kinase A
- Several Mechanisms Cause Termination of the β-Adrenergic Response
- The β-Adrenergic Receptor Is Desensitized by Phosphorylation and by Association with Arrestin
- Cyclic AMP Acts as a Second Messenger for Many Regulatory Molecules
- G Proteins Act as Self-Limiting Switches in Many Processes
- Diacylglycerol, Inositol Trisphosphate, and Ca2+ Have Related Roles as Second Messengers
- Calcium Is a Second Messenger That Is Limited in Space and Time
- 12.3 GPCRs in Vision, Olfaction, and Gustation
- The Vertebrate Eye Uses Classic GPCR Mechanisms
- Vertebrate Olfaction and Gustation Use Mechanisms Similar to the Visual System
- All GPCR Systems Share Universal Features
- 12.4 Receptor Tyrosine Kinases
- Stimulation of the Insulin Receptor Initiates a Cascade of Protein Phosphorylation Reactions
- The Membrane Phospholipid PIP3 Functions at a Branch in Insulin Signaling
- Cross Talk among Signaling Systems Is Common and Complex
- 12.5 Multivalent Adaptor Proteins and Membrane Rafts
- Protein Modules Bind Phosphorylated Tyr, Ser, or Thr Residues in Partner Proteins
- Membrane Rafts and Caveolae Segregate Signaling Proteins
- 12.6 Gated Ion Channels
- Ion Channels Underlie Rapid Electrical Signaling in Excitable Cells
- Voltage-Gated Ion Channels Produce Neuronal Action Potentials
- Neurons Have Receptor Channels That Respond to Different Neurotransmitters
- Toxins Target Ion Channels
- 12.7 Regulation of Transcription by Nuclear Hormone Receptors
- 12.8 Regulation of the Cell Cycle by Protein Kinases
- The Cell Cycle Has Four Stages
- Levels of Cyclin-Dependent Protein Kinases Oscillate
- CDKs Are Regulated by Phosphorylation, Cyclin Degradation, Growth Factors, and Specific Inhibitors
- CDKs Regulate Cell Division by Phosphorylating Critical Proteins
- 12.9 Oncogenes, Tumor Suppressor Genes, and Programmed Cell Death
- Oncogenes Are Mutant Forms of the Genes for Proteins That Regulate the Cell Cycle
- Defects in Certain Genes Remove Normal Restraints on Cell Division
- Apoptosis Is Programmed Cell Suicide
- Chapter Review
- Key Terms
- Problems
- Part II Bioenergetics and Metabolism
第二部分 生物能量学与代谢- Chapter 13 Introduction to Metabolism
第 13 章 代谢介绍- 13.1 Bioenergetics and Thermodynamics
- Biological Energy Transformations Obey the Laws of Thermodynamics
- Standard Free-Energy Change Is Directly Related to the Equilibrium Constant
- Actual Free-Energy Changes Depend on Reactant and Product Concentrations
- Standard Free-Energy Changes Are Additive
- 13.2 Chemical Logic and Common Biochemical Reactions
- Biochemical Reactions Occur in Repeating Patterns
- Biochemical and Chemical Equations Are Not Identical
- 13.3 Phosphoryl Group Transfers and ATP
- The Free-Energy Change for ATP Hydrolysis Is Large and Negative
- Other Phosphorylated Compounds and Thioesters Also Have Large, Negative Free Energies of Hydrolysis
- ATP Provides Energy by Group Transfers, Not by Simple Hydrolysis
- ATP Donates Phosphoryl, Pyrophosphoryl, and Adenylyl Groups
- Assembly of Informational Macromolecules Requires Energy
- Transphosphorylations between Nucleotides Occur in All Cell Types
- 13.4 Biological Oxidation-Reduction Reactions
- The Flow of Electrons Can Do Biological Work
- Oxidation-Reductions Can Be Described as Half-Reactions
- Biological Oxidations Often Involve Dehydrogenation
- Reduction Potentials Measure Affinity for Electrons
- Standard Reduction Potentials Can Be Used to Calculate Free-Energy Change
- A Few Types of Coenzymes and Proteins Serve as Universal Electron Carriers
- NAD Has Important Functions in Addition to Electron Transfer
- Flavin Nucleotides Are Tightly Bound in Flavoproteins
- 13.5 Regulation of Metabolic Pathways
- Cells and Organisms Maintain a Dynamic Steady State
- Both the Amount and the Catalytic Activity of an Enzyme Can Be Regulated
- Reactions Far from Equilibrium in Cells Are Common Points of Regulation
- Adenine Nucleotides Play Special Roles in Metabolic Regulation
- Chapter Review
- Key Terms
- Problems
- Chapter 14 Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway
- 14.1 Glycolysis
- An Overview: Glycolysis Has Two Phases
- The Preparatory Phase of Glycolysis Requires ATP
- The Payoff Phase of Glycolysis Yields ATP and NADH
- The Overall Balance Sheet Shows a Net Gain of Two ATP and Two NADH Per Glucose
- 14.2 Feeder Pathways for Glycolysis
- Endogenous Glycogen and Starch Are Degraded by Phosphorolysis
- Dietary Polysaccharides and Disaccharides Undergo Hydrolysis to Monosaccharides
- 14.3 Fates of Pyruvate
- The Pasteur and Warburg Effects Are Due to Dependence on Glycolysis Alone for ATP Production
- Pyruvate Is the Terminal Electron Acceptor in Lactic Acid Fermentation
- Ethanol Is the Reduced Product in Ethanol Fermentation
- Fermentations Produce Some Common Foods and Industrial Chemicals
- 14.4 Gluconeogenesis
- The First Bypass: Conversion of Pyruvate to Phosphoenolpyruvate Requires Two Exergonic Reactions
- The Second and Third Bypasses Are Simple Dephosphorylations by Phosphatases
- Gluconeogenesis Is Energetically Expensive, But Essential
- Mammals Cannot Convert Fatty Acids to Glucose; Plants and Microorganisms Can
- 14.5 Coordinated Regulation of Glycolysis and Gluconeogenesis
- Hexokinase Isozymes Are Affected Differently by Their Product, Glucose 6-Phosphate
- Phosphofructokinase-1 and Fructose 1,6-Bisphosphatase Are Reciprocally Regulated
- Fructose 2,6-Bisphosphate Is a Potent Allosteric Regulator of PFK-1 and FBPase-1
- Xylulose 5-Phosphate Is a Key Regulator of Carbohydrate and Fat Metabolism
- The Glycolytic Enzyme Pyruvate Kinase Is Allosterically Inhibited by ATP
- Conversion of Pyruvate to Phosphoenolpyruvate Is Stimulated When Fatty Acids Are Available
- Transcriptional Regulation Changes the Number of Enzyme Molecules
- 14.6 Pentose Phosphate Pathway of Glucose Oxidation
- The Oxidative Phase Produces NADPH and Pentose Phosphates
- The Nonoxidative Phase Recycles Pentose Phosphates to Glucose 6-Phosphate
- Glucose 6-Phosphate Is Partitioned between Glycolysis and the Pentose Phosphate Pathway
- Thiamine Deficiency Causes Beriberi and Wernicke-Korsakoff Syndrome
- Chapter Review
- Key Terms
- Problems
- Chapter 15 The Metabolism of Glycogen in Animals
- 15.1 The Structure and Function of Glycogen
- Vertebrate Animals Require a Ready Fuel Source for Brain and Muscle
- Glycogen Granules Have Many Tiers of Branched Chains of d-Glucose
- 15.2 Breakdown and Synthesis of Glycogen
- Glycogen Breakdown Is Catalyzed by Glycogen Phosphorylase
- Glucose 1-Phosphate Can Enter Glycolysis or, in Liver, Replenish Blood Glucose
- The Sugar Nucleotide UDP-Glucose Donates Glucose for Glycogen Synthesis
- Glycogenin Primes the Initial Sugar Residues in Glycogen
- 15.3 Coordinated Regulation of Glycogen Breakdown and Synthesis
- Glycogen Phosphorylase Is Regulated by Hormone-Stimulated Phosphorylation and by Allosteric Effectors
- Glycogen Synthase Also Is Subject to Multiple Levels of Regulation
- Allosteric and Hormonal Signals Coordinate Carbohydrate Metabolism Globally
- Carbohydrate and Lipid Metabolism Are Integrated by Hormonal and Allosteric Mechanisms
- Chapter Review
- Key Terms
- Problems
- Chapter 16 The Citric Acid Cycle
- 16.1 Production of Acetyl-CoA (Activated Acetate)
- Pyruvate Is Oxidized to Acetyl-CoA and CO2
- The PDH Complex Employs Three Enzymes and Five Coenzymes to Oxidize Pyruvate
- The PDH Complex Channels Its Intermediates through Five Reactions
- 16.2 Reactions of the Citric Acid Cycle
- The Sequence of Reactions in the Citric Acid Cycle Makes Chemical Sense
- The Citric Acid Cycle Has Eight Steps
- The Energy of Oxidations in the Cycle Is Efficiently Conserved
- 16.3 The Hub of Intermediary Metabolism
- The Citric Acid Cycle Serves in Both Catabolic and Anabolic Processes
- Anaplerotic Reactions Replenish Citric Acid Cycle Intermediates
- Biotin in Pyruvate Carboxylase Carries One-Carbon (CO2) Groups
- 16.4 Regulation of the Citric Acid Cycle
- Production of Acetyl-CoA by the PDH Complex Is Regulated by Allosteric and Covalent Mechanisms
- The Citric Acid Cycle Is Also Regulated at Three Exergonic Steps
- Citric Acid Cycle Activity Changes in Tumors
- Certain Intermediates Are Channeled through Metabolons
- Chapter Review
- Key Terms
- Problems
- Chapter 17 Fatty Acid Catabolism
- 17.1 Digestion, Mobilization, and Transport of Fats
- Dietary Fats Are Absorbed in the Small Intestine
- Hormones Trigger Mobilization of Stored Triacylglycerols
- Fatty Acids Are Activated and Transported into Mitochondria
- 17.2 Oxidation of Fatty Acids
- The β Oxidation of Saturated Fatty Acids Has Four Basic Steps
- The Four β-Oxidation Steps Are Repeated to Yield Acetyl-CoA and ATP
- Acetyl-CoA Can Be Further Oxidized in the Citric Acid Cycle
- Oxidation of Unsaturated Fatty Acids Requires Two Additional Reactions
- Complete Oxidation of Odd-Number Fatty Acids Requires Three Extra Reactions
- Fatty Acid Oxidation Is Tightly Regulated
- Transcription Factors Turn on the Synthesis of Proteins for Lipid Catabolism
- Genetic Defects in Fatty Acyl–CoA Dehydrogenases Cause Serious Disease
- Peroxisomes Also Carry Out β Oxidation
- Phytanic Acid Undergoes α Oxidation in Peroxisomes
- 17.3 Ketone Bodies
- Ketone Bodies, Formed in the Liver, Are Exported to Other Organs as Fuel
- Ketone Bodies Are Overproduced in Diabetes and during Starvation
- Chapter Review
- Key Terms
- Problems
- Chapter 18 Amino Acid Oxidation and the Production of Urea
- 18.1 Metabolic Fates of Amino Groups
- Dietary Protein Is Enzymatically Degraded to Amino Acids
- Pyridoxal Phosphate Participates in the Transfer of α-Amino Groups to α-Ketoglutarate
- Glutamate Releases Its Amino Group as Ammonia in the Liver
- Glutamine Transports Ammonia in the Bloodstream
- Alanine Transports Ammonia from Skeletal Muscles to the Liver
- Ammonia Is Toxic to Animals
- 18.2 Nitrogen Excretion and the Urea Cycle
- Urea Is Produced from Ammonia in Five Enzymatic Steps
- The Citric Acid and Urea Cycles Can Be Linked
- The Activity of the Urea Cycle Is Regulated at Two Levels
- Pathway Interconnections Reduce the Energetic Cost of Urea Synthesis
- Genetic Defects in the Urea Cycle Can Be Life-Threatening
- 18.3 Pathways of Amino Acid Degradation
- Some Amino Acids Can Contribute to Gluconeogenesis, Others to Ketone Body Formation
- Several Enzyme Cofactors Play Important Roles in Amino Acid Catabolism
- Six Amino Acids Are Degraded to Pyruvate
- Seven Amino Acids Are Degraded to Acetyl-CoA
- Phenylalanine Catabolism Is Genetically Defective in Some People
- Five Amino Acids Are Converted to -Ketoglutarate
- Four Amino Acids Are Converted to Succinyl-CoA
- Branched-Chain Amino Acids Are Not Degraded in the Liver
- Asparagine and Aspartate Are Degraded to Oxaloacetate
- Chapter Review
- Key Terms
- Problems
- Chapter 19 Oxidative Phosphorylation
- 19.1 The Mitochondrial Respiratory Chain
- Electrons Are Funneled to Universal Electron Acceptors
- Electrons Pass through a Series of Membrane-Bound Carriers
- Electron Carriers Function in Multienzyme Complexes
- Mitochondrial Complexes Associate in Respirasomes
- Other Pathways Donate Electrons to the Respiratory Chain via Ubiquinone
- The Energy of Electron Transfer Is Efficiently Conserved in a Proton Gradient
- Reactive Oxygen Species Are Generated during Oxidative Phosphorylation
- 19.2 ATP Synthesis
- In the Chemiosmotic Model, Oxidation and Phosphorylation Are Obligately Coupled
- ATP Synthase Has Two Functional Domains, F[0] and F[1]
- ATP Is Stabilized Relative to ADP on the Surface of F[1]
- The Proton Gradient Drives the Release of ATP from the Enzyme Surface
- Each β Subunit of ATP Synthase Can Assume Three Different Conformations
- Rotational Catalysis Is Key to the Binding-Change Mechanism for ATP Synthesis
- Chemiosmotic Coupling Allows Nonintegral Stoichiometries of O[2] Consumption and ATP Synthesis
- The Proton-Motive Force Energizes Active Transport
- Shuttle Systems Indirectly Convey Cytosolic NADH into Mitochondria for Oxidation
- 19.3 Regulation of Oxidative Phosphorylation
- Oxidative Phosphorylation Is Regulated by Cellular Energy Needs
- An Inhibitory Protein Prevents ATP Hydrolysis during Hypoxia
- Hypoxia Leads to ROS Production and Several Adaptive Responses
- ATP-Producing Pathways Are Coordinately Regulated
- 19.4 Mitochondria in Thermogenesis, Steroid Synthesis, and Apoptosis
- Uncoupled Mitochondria in Brown Adipose Tissue Produce Heat
- Mitochondrial P-450 Monooxygenases Catalyze Steroid Hydroxylations
- Mitochondria Are Central to the Initiation of Apoptosis
- 19.5 Mitochondrial Genes: Their Origin and the Effects of Mutations
- Mitochondria Evolved from Endosymbiotic Bacteria
- Mutations in Mitochondrial DNA Accumulate throughout the Life of the Organism
- Some Mutations in Mitochondrial Genomes Cause Disease
- A Rare Form of Diabetes Results from Defects in the Mitochondria of Pancreatic β Cells
- Chapter Review
- Key Terms
- Problems
- Chapter 20 Photosynthesis and Carbohydrate Synthesis in Plants
- 20.1 Light Absorption
- Chloroplasts Are the Site of Light-Driven Electron Flow and Photosynthesis in Plants
- Chlorophylls Absorb Light Energy for Photosynthesis
- Chlorophylls Funnel Absorbed Energy to Reaction Centers by Exciton Transfer
- 20.2 Photochemical Reaction Centers
- Photosynthetic Bacteria Have Two Types of Reaction Center
- In Vascular Plants, Two Reaction Centers Act in Tandem
- The Cytochrome b[6]f Complex Links Photosystems II and I, Conserving the Energy of Electron Transfer
- Cyclic Electron Transfer Allows Variation in the Ratio of ATP/NADPH Synthesized
- State Transitions Change the Distribution of LHCII between the Two Photosystems
- Water Is Split at the Oxygen-Evolving Center
- 20.3 Evolution of a Universal Mechanism for ATP Synthesis
- A Proton Gradient Couples Electron Flow and Phosphorylation
- The Approximate Stoichiometry of Photophosphorylation Has Been Established
- The ATP Synthase Structure and Mechanism Are Nearly Universal
- 20.4 CO[2]-Assimilation Reactions
- Carbon Dioxide Assimilation Occurs in Three Stages
- Synthesis of Each Triose Phosphate from CO[2] Requires Six NADPH and Nine ATP
- A Transport System Exports Triose Phosphates from the Chloroplast and Imports Phosphate
- Four Enzymes of the Calvin Cycle Are Indirectly Activated by Light
- 20.5 Photorespiration and the C[4] and CAM Pathways
- Photorespiration Results from Rubisco’s Oxygenase Activity
- Phosphoglycolate Is Salvaged in a Costly Set of Reactions in C[3] Plants
- In C[4] Plants, CO[2] Fixation and Rubisco Activity Are Spatially Separated
- In CAM Plants, CO[2] Capture and Rubisco Action Are Temporally Separated
- 20.6 Biosynthesis of Starch, Sucrose, and Cellulose
- ADP-Glucose Is the Substrate for Starch Synthesis in Plant Plastids and for Glycogen Synthesis in Bacteria
- UDP-Glucose Is the Substrate for Sucrose Synthesis in the Cytosol of Leaf Cells
- Conversion of Triose Phosphates to Sucrose and Starch Is Tightly Regulated
- The Glyoxylate Cycle and Gluconeogenesis Produce Glucose in Germinating Seeds
- Cellulose Is Synthesized by Supramolecular Structures in the Plasma Membrane
- Pools of Common Intermediates Link Pathways in Different Organelles
- Chapter Review
- Key Terms
- Problems
- Chapter 21 Lipid Biosynthesis
- 21.1 Biosynthesis of Fatty Acids and Eicosanoids
- Malonyl-CoA Is Formed from Acetyl-CoA and Bicarbonate
- Fatty Acid Synthesis Proceeds in a Repeating Reaction Sequence
- The Mammalian Fatty Acid Synthase Has Multiple Active Sites
- Fatty Acid Synthase Receives the Acetyl and Malonyl Groups
- The Fatty Acid Synthase Reactions Are Repeated to Form Palmitate
- Fatty Acid Synthesis Is a Cytosolic Process in Most Eukaryotes but Takes Place in the Chloroplasts in Plants
- Acetate Is Shuttled out of Mitochondria as Citrate
- Fatty Acid Biosynthesis Is Tightly Regulated
- Long-Chain Saturated Fatty Acids Are Synthesized from Palmitate
- Desaturation of Fatty Acids Requires a Mixed-Function Oxidase
- Eicosanoids Are Formed from 20- and 22-Carbon Polyunsaturated Fatty Acids
- 21.2 Biosynthesis of Triacylglycerols
- Triacylglycerols and Glycerophospholipids Are Synthesized from the Same Precursors
- Triacylglycerol Biosynthesis in Animals Is Regulated by Hormones
- Adipose Tissue Generates Glycerol 3-Phosphate by Glyceroneogenesis
- Thiazolidinediones Treat Type 2 Diabetes by Increasing Glyceroneogenesis
- 21.3 Biosynthesis of Membrane Phospholipids
- Cells Have Two Strategies for Attaching Phospholipid Head Groups
- Pathways for Phospholipid Biosynthesis Are Interrelated
- Eukaryotic Membrane Phospholipids Are Subject to Remodeling
- Plasmalogen Synthesis Requires Formation of an Ether-Linked Fatty Alcohol
- Sphingolipid and Glycerophospholipid Synthesis Share Precursors and Some Mechanisms
- Polar Lipids Are Targeted to Specific Cellular Membranes
- 21.4 Cholesterol, Steroids, and Isoprenoids: Biosynthesis, Regulation, and Transport
- Cholesterol Is Made from Acetyl-CoA in Four Stages
- Cholesterol Has Several Fates
- Cholesterol and Other Lipids Are Carried on Plasma Lipoproteins
- HDL Carries Out Reverse Cholesterol Transport
- Cholesteryl Esters Enter Cells by Receptor-Mediated Endocytosis
- Cholesterol Synthesis and Transport Are Regulated at Several Levels
- Dysregulation of Cholesterol Metabolism Can Lead to Cardiovascular Disease
- Reverse Cholesterol Transport by HDL Counters Plaque Formation and Atherosclerosis
- Steroid Hormones Are Formed by Side-Chain Cleavage and Oxidation of Cholesterol
- Intermediates in Cholesterol Biosynthesis Have Many Alternative Fates
- Chapter Review
- Key Terms
- Problems
- Chapter 22 Biosynthesis of Amino Acids, Nucleotides, and Related Molecules
- 22.1 Overview of Nitrogen Metabolism
- A Global Nitrogen Cycling Network Maintains a Pool of Biologically Available Nitrogen
- Nitrogen Is Fixed by Enzymes of the Nitrogenase Complex
- Ammonia Is Incorporated into Biomolecules through Glutamate and Glutamine
- Glutamine Synthetase Is a Primary Regulatory Point in Nitrogen Metabolism
- Several Classes of Reactions Play Special Roles in the Biosynthesis of Amino Acids and Nucleotides
- 22.2 Biosynthesis of Amino Acids
- Organisms Vary Greatly in Their Ability to Synthesize the 20 Common Amino Acids
- α-Ketoglutarate Gives Rise to Glutamate, Glutamine, Proline, and Arginine
- Serine, Glycine, and Cysteine Are Derived from 3-Phosphoglycerate
- Three Nonessential and Six Essential Amino Acids Are Synthesized from Oxaloacetate and Pyruvate
- Chorismate Is a Key Intermediate in the Synthesis of Tryptophan, Phenylalanine, and Tyrosine
- Histidine Biosynthesis Uses Precursors of Purine Biosynthesis
- Amino Acid Biosynthesis Is under Allosteric Regulation
- 22.3 Molecules Derived from Amino Acids
- Glycine Is a Precursor of Porphyrins
- Heme Degradation Has Multiple Functions
- Amino Acids Are Precursors of Creatine and Glutathione
- d-Amino Acids Are Found Primarily in Bacteria
- Aromatic Amino Acids Are Precursors of Many Plant Substances
- Biological Amines Are Products of Amino Acid Decarboxylation
- Arginine Is the Precursor for Biological Synthesis of Nitric Oxide
- 22.4 Biosynthesis and Degradation of Nucleotides
- De Novo Purine Nucleotide Synthesis Begins with PRPP
- Purine Nucleotide Biosynthesis Is Regulated by Feedback Inhibition
- Pyrimidine Nucleotides Are Made from Aspartate, PRPP, and Carbamoyl Phosphate
- Pyrimidine Nucleotide Biosynthesis Is Regulated by Feedback Inhibition
- Nucleoside Monophosphates Are Converted to Nucleoside Triphosphates
- Ribonucleotides Are the Precursors of Deoxyribonucleotides
- Thymidylate Is Derived from dCDP and dUMP
- Degradation of Purines and Pyrimidines Produces Uric Acid and Urea, Respectively
- Purine and Pyrimidine Bases Are Recycled by Salvage Pathways
- Excess Uric Acid Causes Gout
- Many Chemotherapeutic Agents Target Enzymes in Nucleotide Biosynthetic Pathways
- Chapter Review
- Key Terms
- Problems
- Chapter 23 Hormonal Regulation and Integration of Mammalian Metabolism
- 23.1 Hormone Structure and Action
- Hormones Act through Specific High-Affinity Cellular Receptors
- Hormones Are Chemically Diverse
- Some Hormones Are Released by a “Top-Down” Hierarchy of Neuronal and Hormonal Signals
- “Bottom-Up” Hormonal Systems Send Signals Back to the Brain and to Other Tissues
- 23.2 Tissue-Specific Metabolism
- The Liver Processes and Distributes Nutrients
- Adipose Tissues Store and Supply Fatty Acids
- Brown and Beige Adipose Tissues Are Thermogenic
- Muscles Use ATP for Mechanical Work
- The Brain Uses Energy for Transmission of Electrical Impulses
- Blood Carries Oxygen, Metabolites, and Hormones
- 23.3 Hormonal Regulation of Fuel Metabolism
- Insulin Counters High Blood Glucose in the Well-Fed State
- Pancreatic β Cells Secrete Insulin in Response to Changes in Blood Glucose
- Glucagon Counters Low Blood Glucose
- During Fasting and Starvation, Metabolism Shifts to Provide Fuel for the Brain
- Epinephrine Signals Impending Activity
- Cortisol Signals Stress, Including Low Blood Glucose
- 23.4 Obesity and the Regulation of Body Mass
- Adipose Tissue Has Important Endocrine Functions
- Leptin Stimulates Production of Anorexigenic Peptide Hormones
- Leptin Triggers a Signaling Cascade That Regulates Gene Expression
- Adiponectin Acts through AMPK to Increase Insulin Sensitivity
- AMPK Coordinates Catabolism and Anabolism in Response to Metabolic Stress
- The mTORC1 Pathway Coordinates Cell Growth with the Supply of Nutrients and Energy
- Diet Regulates the Expression of Genes Central to Maintaining Body Mass
- Short-Term Eating Behavior Is Influenced by Ghrelin, PPY3–36, and Cannabinoids
- Microbial Symbionts in the Gut Influence Energy Metabolism and Adipogenesis
- 23.5 Diabetes Mellitus
- Diabetes Mellitus Arises from Defects in Insulin Production or Action
- Carboxylic Acids (Ketone Bodies) Accumulate in the Blood of Those with Untreated Diabetes
- In Type 2 Diabetes the Tissues Become Insensitive to Insulin
- Type 2 Diabetes Is Managed with Diet, Exercise, Medication, and Surgery
- Chapter Review
- Key Terms
- Problems
- Part III Information Pathways
- Chapter 24 Genes and Chromosomes
- 24.1 Chromosomal Elements
- Genes Are Segments of DNA That Code for Polypeptide Chains and RNAs
- DNA Molecules Are Much Longer than the Cellular or Viral Packages That Contain Them
- Eukaryotic Genes and Chromosomes Are Very Complex
- 24.2 DNA Supercoiling
- Most Cellular DNA Is Underwound
- DNA Underwinding Is Defined by Topological Linking Number
- Topoisomerases Catalyze Changes in the Linking Number of DNA
- DNA Compaction Requires a Special Form of Supercoiling
- 24.3 The Structure of Chromosomes
- Chromatin Consists of DNA, Proteins, and RNA
- Histones Are Small, Basic Proteins
- Nucleosomes Are the Fundamental Organizational Units of Chromatin
- Nucleosomes Are Packed into Highly Condensed Chromosome Structures
- Condensed Chromosome Structures Are Maintained by SMC Proteins
- Bacterial DNA Is Also Highly Organized
- Chapter Review
- Key Terms
- Problems
- Chapter 25 DNA Metabolism
- 25.1 DNA Replication
- DNA Replication Follows a Set of Fundamental Rules
- DNA Is Degraded by Nucleases
- DNA Is Synthesized by DNA Polymerases
- Replication Is Very Accurate
- E. coli Has at Least Five DNA Polymerases
- DNA Replication Requires Many Enzymes and Protein Factors
- Replication of the E. coli Chromosome Proceeds in Stages
- Replication in Eukaryotic Cells Is Similar but More Complex
- Viral DNA Polymerases Provide Targets for Antiviral Therapy
- 25.2 DNA Repair
- Mutations Are Linked to Cancer
- All Cells Have Multiple DNA Repair Systems
- The Interaction of Replication Forks with DNA Damage Can Lead to Error-Prone Translesion DNA Synthesis
- 25.3 DNA Recombination
- Bacterial Homologous Recombination Is a DNA Repair Function
- Eukaryotic Homologous Recombination Is Required for Proper Chromosome Segregation during Meiosis
- Some Double-Strand Breaks Are Repaired by Nonhomologous End Joining
- Site-Specific Recombination Results in Precise DNA Rearrangements
- Transposable Genetic Elements Move from One Location to Another
- Immunoglobulin Genes Assemble by Recombination
- Chapter Review
- Key Terms
- Problems
- Chapter 26 RNA Metabolism
- 26.1 DNA-Dependent Synthesis of RNA
- RNA Is Synthesized by RNA Polymerases
- RNA Synthesis Begins at Promoters
- Transcription Is Regulated at Several Levels
- Specific Sequences Signal Termination of RNA Synthesis
- Eukaryotic Cells Have Three Kinds of Nuclear RNA Polymerases
- RNA Polymerase II Requires Many Other Protein Factors for Its Activity
- RNA Polymerases Are Drug Targets
- 26.2 RNA Processing
- Eukaryotic mRNAs Are Capped at the 5′ End
- Both Introns and Exons Are Transcribed from DNA into RNA
- RNA Catalyzes the Splicing of Introns
- In Eukaryotes the Spliceosome Carries out Nuclear pre-mRNA Splicing
- Proteins Catalyze Splicing of tRNAs
- Eukaryotic mRNAs Have a Distinctive 3′ End Structure
- A Gene Can Give Rise to Multiple Products by Differential RNA Processing
- Ribosomal RNAs and tRNAs Also Undergo Processing
- Special-Function RNAs Undergo Several Types of Processing
- Cellular mRNAs Are Degraded at Different Rates
- 26.3 RNA-Dependent Synthesis of RNA and DNA
- Reverse Transcriptase Produces DNA from Viral RNA
- Some Retroviruses Cause Cancer and AIDS
- Many Transposons, Retroviruses, and Introns May Have a Common Evolutionary Origin
- Telomerase Is a Specialized Reverse Transcriptase
- Some RNAs Are Replicated by RNA-Dependent RNA Polymerase
- RNA-Dependent RNA Polymerases Share a Common Structural Fold
- 26.4 Catalytic RNAs and the RNA World Hypothesis
- Ribozymes Share Features with Protein Enzymes
- Ribozymes Participate in a Variety of Biological Processes
- Ribozymes Provide Clues to the Origin of Life in an RNA World
- Chapter Review
- Key Terms
- Problems
- Chapter 27 Protein Metabolism
- 27.1 The Genetic Code
- The Genetic Code Was Cracked Using Artificial mRNA Templates
- Wobble Allows Some tRNAs to Recognize More than One Codon
- The Genetic Code Is Mutation-Resistant
- Translational Frameshifting Affects How the Code Is Read
- Some mRNAs Are Edited before Translation
- 27.2 Protein Synthesis
- The Ribosome Is a Complex Supramolecular Machine
- Transfer RNAs Have Characteristic Structural Features
- Stage 1: Aminoacyl-tRNA Synthetases Attach the Correct Amino Acids to Their tRNAs
- Stage 2: A Specific Amino Acid Initiates Protein Synthesis
- Stage 3: Peptide Bonds Are Formed in the Elongation Stage
- Stage 4: Termination of Polypeptide Synthesis Requires a Special Signal
- Stage 5: Newly Synthesized Polypeptide Chains Undergo Folding and Processing
- Protein Synthesis Is Inhibited by Many Antibiotics and Toxins
- 27.3 Protein Targeting and Degradation
- Posttranslational Modification of Many Eukaryotic Proteins Begins in the Endoplasmic Reticulum
- Glycosylation Plays a Key Role in Protein Targeting
- Signal Sequences for Nuclear Transport Are Not Cleaved
- Bacteria Also Use Signal Sequences for Protein Targeting
- Cells Import Proteins by Receptor-Mediated Endocytosis
- Protein Degradation Is Mediated by Specialized Systems in All Cells
- Chapter Review
- Key Terms
- Problems
- Chapter 28 Regulation of Gene Expression
- 28.1 The Proteins and RNAs of Gene Regulation
- RNA Polymerase Binds to DNA at Promoters
- Transcription Initiation Is Regulated by Proteins and RNAs
- Many Bacterial Genes Are Clustered and Regulated in Operons
- The lac Operon Is Subject to Negative Regulation
- Regulatory Proteins Have Discrete DNA-Binding Domains
- Regulatory Proteins Also Have Protein-Protein Interaction Domains
- 28.2 Regulation of Gene Expression in Bacteria
- The lac Operon Undergoes Positive Regulation
- Many Genes for Amino Acid Biosynthetic Enzymes Are Regulated by Transcription Attenuation
- Induction of the SOS Response Requires Destruction of Repressor Proteins
- Synthesis of Ribosomal Proteins Is Coordinated with rRNA Synthesis
- The Function of Some mRNAs Is Regulated by Small RNAs in Cis or in Trans
- Some Genes Are Regulated by Genetic Recombination
- 28.3 Regulation of Gene Expression in Eukaryotes
- Transcriptionally Active Chromatin Is Structurally Distinct from Inactive Chromatin
- Most Eukaryotic Promoters Are Positively Regulated
- DNA-Binding Activators and Coactivators Facilitate Assembly of the Basal Transcription Factors
- The Genes of Galactose Metabolism in Yeast Are Subject to Both Positive and Negative Regulation
- Transcription Activators Have a Modular Structure
- Eukaryotic Gene Expression Can Be Regulated by Intercellular and Intracellular Signals
- Regulation Can Result from Phosphorylation of Nuclear Transcription Factors
- Many Eukaryotic mRNAs Are Subject to Translational Repression
- Posttranscriptional Gene Silencing Is Mediated by RNA Interference
- RNA-Mediated Regulation of Gene Expression Takes Many Forms in Eukaryotes
- Development Is Controlled by Cascades of Regulatory Proteins
- Stem Cells Have Developmental Potential That Can Be Controlled
- Chapter Review
- Key Terms
- Problems
- Note
- Abbreviated Solutions to Problems
- Glossary
- Index
- Resources
- Back Cover