Lehninger Principles of Biochemistry 8th edition

About this Book
Cover Page
Halftitle Page
Title Page
Copyright
Dedication
About the Authors
A Note on the Nature of Science
Overview of key features
Tools and Resources to Support Teaching
Acknowledgments
Contents in Brief
Contents
Chapter 1 The Foundations of Biochemistry
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
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
Chapter 13 Introduction to Metabolism
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
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