Lehninger Principles of Biochemistry
Námskeið
- LEF406G Lífefnafræði 2
- LEF302G Lífefnafræði 1
Lýsing:
Available for the first time in Achieve, the definitive reference text for biochemistry Lehninger Principles of Biochemistry, 8e helps students focus on the most important aspects of biochemistry- the principles! Dave Nelson, Michael Cox, and new co-author Aaron Hoskins identify the most important principles of biochemistry and direct student attention to these with icons and resources targeted to each principle.
The 8th edition has been fully updated for focus, approachability, and up-to-date content. New and updated end-of-chapter questions -all available in the Achieve problem library with error-specific feedback and thorough solutions. These questions went through a rigorous development process to ensure they were robust, engaging and accurate. Lehninger Principles of Biochemistry, 8e continues to help students navigate the complex discipline of biochemistry with a clear and coherent presentation.
Renowned authors David Nelson, Michael Cox, and new co-author Aaron Hoskins have focused this eighth edition around the fundamental principles to help students understand and navigate the most important aspects of biochemistry. Text features and digital resources in the new Achieve platform emphasize this focus on the principles, while coverage of recent discoveries and the most up-to-date research provide fascinating context for learning the dynamic discipline of biochemistry.
Annað
- Höfundar: David L. Nelson, Michael Cox
- Útgáfa:8
- Útgáfudagur: 01-07-2021
- Hægt að prenta út 2 bls.
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- Format:ePub
- ISBN 13: 9781319322397
- Print ISBN: 9781319381493
- ISBN 10: 1319322395
Efnisyfirlit
- 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
- 1.1 Cellular Foundations
- 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
- 2.1 Weak Interactions in Aqueous Systems
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 13.1 Bioenergetics and Thermodynamics
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 24.1 Chromosomal Elements
- 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
- 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
- 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
- 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
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