1. Unity and Diversity1.1 Water0/01.1.1 Properties of Water1.1.2 Molecular Structure and Bonding1.1.3 Cohesion, Adhesion, and Surface Tension1.1.4 Solvent Properties and Metabolism1.1.5 Physical Properties and Aquatic Life1.1.6 Extraplanetary Origin and Life Search1.2 Nucleic acids0/01.2.1 DNA and RNA Basics1.2.2 Molecular Structure and Bonding1.2.3 DNA Replication and Diversity1.2.4 Advanced Concepts in Nucleic Acids1.3 Origins of Cells (HL only)0/01.3.1 Conditions on Early Earth1.3.2 Cells as Smallest Units of Life1.3.3 Spontaneous Origin of Cells1.3.4 Evidence for Origin of Carbon Compounds1.3.5 Formation of Vesicles1.3.6 RNA as First Genetic Material1.3.7 Evidence for Last Universal Common Ancestor (LUCA)1.3.8 Estimation of Dates1.3.9 LUCA's Evolution near Hydrothermal Vents1.4 Cell Structure0/01.4.1 Cells as Basic Structural Units1.4.2 Microscopy Skills1.4.3 Developments in Microscopy1.4.4 Structures Common to All Cells1.4.5 Prokaryote Cell Structure1.4.6 Eukaryote Cell Structure1.4.7 Processes in Unicellular Organisms1.4.8 Differences in Eukaryotic Cell Structure1.4.9 Atypical Cell Structure1.4.10 Cell Types and Structures in Micrographs1.4.11 Drawing and Annotation1.4.12 Origin of Eukaryotic Cells1.4.13 Cell Differentiation1.4.14 Evolution of Multicellularity1.5 Viruses (HL only)0/01.5.1 Structural Features1.5.2 Diversity in Viruses1.5.3 Lytic Cycle1.5.4 Lysogenic Cycle1.5.5 Evidence for Virus Origins1.5.6 Rapid Evolution in Viruses1.6 Diversity of Organisms0/01.6.1 Organismal Variation1.6.2 Species Definition1.6.3 Binomial Naming System1.6.4 Speciation Process1.6.5 Chromosomal Diversity1.6.6 Genomic Unity and Diversity1.6.7 Genome Size and Complexity1.6.8 Genome Sequencing1.6.9 Asexual Reproduction and Species Concept1.7 Classification and Cladistics (HL only)0/01.7.1 Need for Classification1.7.2 Traditional vs. Cladistic Classification 1.7.3 Clades and Evolutionary Relationships1.7.4 Molecular Clock and Cladograms1.7.5 Cladogram Analysis1.7.6 Reclassification Case Studies1.8 Evolution and Speciation0/01.8.1 Evolution as Change in Heritable Characteristics1.8.2 Evidence for Evolution from Sequences1.8.3 Evidence for Evolution from Selective Breed1.8.4 Evidence for Evolution from Homologous Structures1.8.5 Convergent Evolution1.8.6 Speciation by Splitting of Pre-existing Species1.8.7 Roles of Reproductive Isolation and Differential Selection in Speciation1.8.8 Differences and Similarities between Sympatric and Allopatric Speciation (HL Only)1.8.9 Adaptive Radiation as a Source of Biodiversity (HL Only)1.8.10 Barriers to Hybridization and Sterility of Interspecific Hybrids (HL Only)1.8.11 Abrupt Speciation in Plants by Hybridization and Polyploidy (HL Only)1.9 Conservation of Biodiversity0/01.9.1 Biodiversity Definition1.9.2 Comparisons between Current and Past Biodiversity1.9.3 Causes of Anthropogenic Species Extinction1.9.4 Causes of Ecosystem Loss1.9.5 Evidence for a Biodiversity Crisis1.9.6 Causes of the Current Biodiversity Crisis1.9.7 Approaches to Biodiversity Conservation1.9.8 Selection of EDGE Species for Conservation1. Unity and Diversity1.1 Water0/01.1.1 Properties of Water1.1.2 Molecular Structure and Bonding1.1.3 Cohesion, Adhesion, and Surface Tension1.1.4 Solvent Properties and Metabolism1.1.5 Physical Properties and Aquatic Life1.1.6 Extraplanetary Origin and Life Search1.2 Nucleic acids0/01.2.1 DNA and RNA Basics1.2.2 Molecular Structure and Bonding1.2.3 DNA Replication and Diversity1.2.4 Advanced Concepts in Nucleic Acids1.3 Origins of Cells (HL only)0/01.3.1 Conditions on Early Earth1.3.2 Cells as Smallest Units of Life1.3.3 Spontaneous Origin of Cells1.3.4 Evidence for Origin of Carbon Compounds1.3.5 Formation of Vesicles1.3.6 RNA as First Genetic Material1.3.7 Evidence for Last Universal Common Ancestor (LUCA)1.3.8 Estimation of Dates1.3.9 LUCA's Evolution near Hydrothermal Vents1.4 Cell Structure0/01.4.1 Cells as Basic Structural Units1.4.2 Microscopy Skills1.4.3 Developments in Microscopy1.4.4 Structures Common to All Cells1.4.5 Prokaryote Cell Structure1.4.6 Eukaryote Cell Structure1.4.7 Processes in Unicellular Organisms1.4.8 Differences in Eukaryotic Cell Structure1.4.9 Atypical Cell Structure1.4.10 Cell Types and Structures in Micrographs1.4.11 Drawing and Annotation1.4.12 Origin of Eukaryotic Cells1.4.13 Cell Differentiation1.4.14 Evolution of Multicellularity1.5 Viruses (HL only)0/01.5.1 Structural Features1.5.2 Diversity in Viruses1.5.3 Lytic Cycle1.5.4 Lysogenic Cycle1.5.5 Evidence for Virus Origins1.5.6 Rapid Evolution in Viruses1.6 Diversity of Organisms0/01.6.1 Organismal Variation1.6.2 Species Definition1.6.3 Binomial Naming System1.6.4 Speciation Process1.6.5 Chromosomal Diversity1.6.6 Genomic Unity and Diversity1.6.7 Genome Size and Complexity1.6.8 Genome Sequencing1.6.9 Asexual Reproduction and Species Concept1.7 Classification and Cladistics (HL only)0/01.7.1 Need for Classification1.7.2 Traditional vs. Cladistic Classification 1.7.3 Clades and Evolutionary Relationships1.7.4 Molecular Clock and Cladograms1.7.5 Cladogram Analysis1.7.6 Reclassification Case Studies1.8 Evolution and Speciation0/01.8.1 Evolution as Change in Heritable Characteristics1.8.2 Evidence for Evolution from Sequences1.8.3 Evidence for Evolution from Selective Breed1.8.4 Evidence for Evolution from Homologous Structures1.8.5 Convergent Evolution1.8.6 Speciation by Splitting of Pre-existing Species1.8.7 Roles of Reproductive Isolation and Differential Selection in Speciation1.8.8 Differences and Similarities between Sympatric and Allopatric Speciation (HL Only)1.8.9 Adaptive Radiation as a Source of Biodiversity (HL Only)1.8.10 Barriers to Hybridization and Sterility of Interspecific Hybrids (HL Only)1.8.11 Abrupt Speciation in Plants by Hybridization and Polyploidy (HL Only)1.9 Conservation of Biodiversity0/01.9.1 Biodiversity Definition1.9.2 Comparisons between Current and Past Biodiversity1.9.3 Causes of Anthropogenic Species Extinction1.9.4 Causes of Ecosystem Loss1.9.5 Evidence for a Biodiversity Crisis1.9.6 Causes of the Current Biodiversity Crisis1.9.7 Approaches to Biodiversity Conservation1.9.8 Selection of EDGE Species for Conservation2. Form and FunctionPremium2.1 Carbohydrates and Lipids0/02.1.1 Chemical Properties of Carbon2.1.2 Macromolecule Production2.1.3 Hydrolysis Reactions 2.1.4 Monosaccharide Properties2.1.5 Polysaccharides as Energy Storage2.1.6 Cellulose as Structural Polysaccharide2.1.7 Glycoproteins in Cell-Cell Recognition2.1.8 Lipid Hydrophobic Properties2.2 Proteins0/02.2.1 Amino Acids and Peptide Formation2.2.2 Protein Diversity and Structure2.2.3 Chemical Diversity in R-groups (HL Only)2.2.4 Protein Conformation (HL Only)2.2.5 Tertiary and Quaternary Structures (HL Only)2.2.6 Form, Function, and Environment (HL Only)2.2.7 Proteins in Biological Processes (HL Only)2.2.8 Advanced Protein Structures and Functions (HL Only)2.3 Membranes and Membrane Transport0/02.3.1 Lipid Bilayers as Basis of Cell Membranes2.3.2 Simple Diffusion Across Membranes2.3.3 Integral and Peripheral Proteins in Membranes2.3.4 Water Movement Across Membranes and Osmosis2.3.6 Membrane Composition and Fluidity (HL Only)2.3.7 Membrane Structure and Function (HL Only)2.3.8 Active Transport and Pump Proteins (HL Only)2.3.9 Additional Membrane Processes (HL Only)2.4 Organelles and Compartmentalization0/02.4.1 Organelles in Cells2.4.2 Nucleus and Cytoplasm Separation2.4.3 Mitochondrion and Chloroplast Adaptations (HL Only)2.4.4 Double Membrane of the Nucleus (HL Only)2.4.5 Ribosomes, ER, Golgi, and Vesicles (HL Only)2.5 Cell Specialization0/02.5.1 Unspecialized Cells and Differentiation2.5.2 Properties of Stem Cells2.5.3 Stem Cell Niches in Adult Humans2.5.4 Types of Stem Cells2.5.5 Cell Size and Specialization (HL Only)2.6 Gas Exchange0/02.6.1 Vital Function & Surface Properties2.6.2 Concentration Gradients & Mammalian Adaptations2.6.3 Lung Ventilation & Volumes2.6.4 Leaf Adaptations & Tissue Distribution2.6.5 Transpiration & Stomatal Density2.6.6 Hemoglobin Adaptations & Bohr Shift (HL Only)2.7 Transport0/02.7.2 Heart Health and Pulse Rates2.7.3 Plant Transport Systems2.7.4 Tissue Fluid and Lymphatic System (HL Only)2.7.5 Circulatory Adaptations (HL Only)2.7.6 Root and Sap Pressure (HL Only)2.8 Muscle and Motility (HL only)0/02.8.1 Movement in Organisms (HL Only)2.8.2 Muscle Structure and Function (HL Only)2.8.3 Joint Movement and Function (HL Only)2.8.4 Intercostal Muscles (HL Only)2.8.5 Locomotion and Adaptations (HL Only)2.9 Adaptation to Environment0/02.9.1 Understanding Habitats and Adaptations2.9.2 Abiotic Variables and Species Distribution2.9.3 Ecosystems: Coral Reefs and Biomes2.9.4 Adaptations in Extreme Environments2.10 Ecological Niches0/02.10.1 Understanding Ecological Niches2.10.2 Modes of Nutrition and Organism Classification2.10.3 Adaptations and Diet in Hominidae2.10.4 Plant-Herbivore and Predator-Prey Dynamics2.10.5 Adaptations for Light Harvesting in Plants2.10.6 Niche Fundamentals and Competition2. Form and FunctionPremium2.1 Carbohydrates and Lipids0/02.1.1 Chemical Properties of Carbon2.1.2 Macromolecule Production2.1.3 Hydrolysis Reactions 2.1.4 Monosaccharide Properties2.1.5 Polysaccharides as Energy Storage2.1.6 Cellulose as Structural Polysaccharide2.1.7 Glycoproteins in Cell-Cell Recognition2.1.8 Lipid Hydrophobic Properties2.2 Proteins0/02.2.1 Amino Acids and Peptide Formation2.2.2 Protein Diversity and Structure2.2.3 Chemical Diversity in R-groups (HL Only)2.2.4 Protein Conformation (HL Only)2.2.5 Tertiary and Quaternary Structures (HL Only)2.2.6 Form, Function, and Environment (HL Only)2.2.7 Proteins in Biological Processes (HL Only)2.2.8 Advanced Protein Structures and Functions (HL Only)2.3 Membranes and Membrane Transport0/02.3.1 Lipid Bilayers as Basis of Cell Membranes2.3.2 Simple Diffusion Across Membranes2.3.3 Integral and Peripheral Proteins in Membranes2.3.4 Water Movement Across Membranes and Osmosis2.3.6 Membrane Composition and Fluidity (HL Only)2.3.7 Membrane Structure and Function (HL Only)2.3.8 Active Transport and Pump Proteins (HL Only)2.3.9 Additional Membrane Processes (HL Only)2.4 Organelles and Compartmentalization0/02.4.1 Organelles in Cells2.4.2 Nucleus and Cytoplasm Separation2.4.3 Mitochondrion and Chloroplast Adaptations (HL Only)2.4.4 Double Membrane of the Nucleus (HL Only)2.4.5 Ribosomes, ER, Golgi, and Vesicles (HL Only)2.5 Cell Specialization0/02.5.1 Unspecialized Cells and Differentiation2.5.2 Properties of Stem Cells2.5.3 Stem Cell Niches in Adult Humans2.5.4 Types of Stem Cells2.5.5 Cell Size and Specialization (HL Only)2.6 Gas Exchange0/02.6.1 Vital Function & Surface Properties2.6.2 Concentration Gradients & Mammalian Adaptations2.6.3 Lung Ventilation & Volumes2.6.4 Leaf Adaptations & Tissue Distribution2.6.5 Transpiration & Stomatal Density2.6.6 Hemoglobin Adaptations & Bohr Shift (HL Only)2.7 Transport0/02.7.2 Heart Health and Pulse Rates2.7.3 Plant Transport Systems2.7.4 Tissue Fluid and Lymphatic System (HL Only)2.7.5 Circulatory Adaptations (HL Only)2.7.6 Root and Sap Pressure (HL Only)2.8 Muscle and Motility (HL only)0/02.8.1 Movement in Organisms (HL Only)2.8.2 Muscle Structure and Function (HL Only)2.8.3 Joint Movement and Function (HL Only)2.8.4 Intercostal Muscles (HL Only)2.8.5 Locomotion and Adaptations (HL Only)2.9 Adaptation to Environment0/02.9.1 Understanding Habitats and Adaptations2.9.2 Abiotic Variables and Species Distribution2.9.3 Ecosystems: Coral Reefs and Biomes2.9.4 Adaptations in Extreme Environments2.10 Ecological Niches0/02.10.1 Understanding Ecological Niches2.10.2 Modes of Nutrition and Organism Classification2.10.3 Adaptations and Diet in Hominidae2.10.4 Plant-Herbivore and Predator-Prey Dynamics2.10.5 Adaptations for Light Harvesting in Plants2.10.6 Niche Fundamentals and Competition3. Interaction and InterdependancePremium3.1 Enzymes and Metabolism0/03.1.1 Understanding Enzymes and Metabolism3.1.2 Factors Affecting Enzyme Activity3.1.3 Enzyme Kinetics and Activation Energy3.1.4 Intracellular and Extracellular Enzymes (HL only)3.1.5 Pathways in Metabolism (HL only)3.1.6 Competitive, Non-competitive Inhibition and Feedback Inhibition (HL only)3.1.7 Enzyme Inhibition and Resistance3.2 Cell Respiration0/03.2.1 ATP and Cell Respiration3.2.2 Anaerobic vs. Aerobic Respiration3.2.3 Investigating Cell Respiration3.2.4 Role of NAD in Oxidation-Reduction (HL only)3.2.5 Glycolysis and Lactate Formation (HL only)3.2.6 Anaerobic Respiration in Yeast (HL only)3.2.7 The Krebs Cycle and Electron Transport (HL only)3.2.8 Chemiosmosis and ATP Synthesis (HL only)3.2.9 Oxygen's Role and Respiratory Substrates (HL only)3.3 Photosynthesis0/03.3.1 Energy Transformation in Photosynthesis3.3.2 Photosynthetic Pigments and Light Absorption3.3.3 Investigating Photosynthesis Limiting Factors3.3.4 Predicting Photosynthesis and Plant Growth3.3.5 Photosystems and Pigment Arrays (HL only)3.3.6 Oxygen Generation and ATP Production (HL only)3.3.7 NADP Reduction and Thylakoid Functions (HL only)3.3.8 The Calvin Cycle and Carbon Fixation (HL only)3.3.9 Interdependence of Photosynthetic Reactions (HL only)3.4 Chemical Signalling (HL only)0/03.4.1 Receptors and Ligands in Chemical Signalling (HL only)3.4.2 Diversity and Function of Signalling Chemicals (HL only)3.4.3 Localization and Impact of Signalling Molecules (HL only)3.4.4 Receptor Types and Signal Transduction (HL only)3.4.5 Transmembrane Receptors and Cellular Responses (HL only)3.4.6 Hormone-Receptor Interactions and Cellular Effects (HL only)3.4.7 Intracellular Receptors and Gene Expression (HL only)3.5 Neural Signalling0/03.5.1 Neurons and Their Role in the Nervous System3.5.2 Resting and Action Potentials in Neurons3.5.3 Speed Variations in Nerve Impulse Transmission3.5.4 Synaptic Transmission and Neurotransmitters3.5.5 Action Potential Dynamics (HL only)3.5.6 Advanced Neural Signalling Techniques (HL only)3.5.7 Exogenous Chemicals and Neural Regulation (HL only)3.5.8 Complex Neural Interactions and Consciousness (HL only)3.6 Integration of Body Systems0/03.6.1 System Integration and Coordination3.6.2 Hormonal and Nervous Signalling3.6.3 Central Information Processing3.6.4 Sensory Input and Motor Output3.6.5 Reflex Arcs and Movement Coordination3.6.6 Circadian Rhythms and Hormonal Secretion3.6.7 Endocrine System Control3.6.8 Feedback Mechanisms in Body Regulation3.6.9 Plant Responses and Phytohormones (HL only)3.6.10 Positive Feedback in Plant Processes (HL only)3.7 Defence Against Disease0/03.7.1 Pathogens and Disease3.7.2 Body's Primary Defences3.7.3 Innate vs. Adaptive Immunity3.7.4 Lymphocytes and Antibody Production3.7.5 Immunity and HIV3.7.6 Antibiotics and Resistance3.7.7 Zoonoses and COVID-193.7.8 Vaccines, Herd Immunity, and Pandemics3.8 Populations and Communities0/03.8.1 Population Dynamics3.8.2 Carrying Capacity and Population Control3.8.3 Community Interactions3.8.4 Invasive Species and Competition3.8.5 Predator-Prey Dynamics3.8.6 Allelopathy and Antibiotic Secretion3.9 Transfers of Energy and Matter0/03.9.1 Ecosystems and Energy Sources3.9.2 Autotrophs and Heterotrophs3.9.3 Trophic Levels and Energy Pyramids3.9.4 Energy Loss and Ecosystem Structure3.9.5 The Carbon Cycle3.9.6 Analysis of Carbon Flux3.9.7 Element Recycling in Ecosystems3. Interaction and InterdependancePremium3.1 Enzymes and Metabolism0/03.1.1 Understanding Enzymes and Metabolism3.1.2 Factors Affecting Enzyme Activity3.1.3 Enzyme Kinetics and Activation Energy3.1.4 Intracellular and Extracellular Enzymes (HL only)3.1.5 Pathways in Metabolism (HL only)3.1.6 Competitive, Non-competitive Inhibition and Feedback Inhibition (HL only)3.1.7 Enzyme Inhibition and Resistance3.2 Cell Respiration0/03.2.1 ATP and Cell Respiration3.2.2 Anaerobic vs. Aerobic Respiration3.2.3 Investigating Cell Respiration3.2.4 Role of NAD in Oxidation-Reduction (HL only)3.2.5 Glycolysis and Lactate Formation (HL only)3.2.6 Anaerobic Respiration in Yeast (HL only)3.2.7 The Krebs Cycle and Electron Transport (HL only)3.2.8 Chemiosmosis and ATP Synthesis (HL only)3.2.9 Oxygen's Role and Respiratory Substrates (HL only)3.3 Photosynthesis0/03.3.1 Energy Transformation in Photosynthesis3.3.2 Photosynthetic Pigments and Light Absorption3.3.3 Investigating Photosynthesis Limiting Factors3.3.4 Predicting Photosynthesis and Plant Growth3.3.5 Photosystems and Pigment Arrays (HL only)3.3.6 Oxygen Generation and ATP Production (HL only)3.3.7 NADP Reduction and Thylakoid Functions (HL only)3.3.8 The Calvin Cycle and Carbon Fixation (HL only)3.3.9 Interdependence of Photosynthetic Reactions (HL only)3.4 Chemical Signalling (HL only)0/03.4.1 Receptors and Ligands in Chemical Signalling (HL only)3.4.2 Diversity and Function of Signalling Chemicals (HL only)3.4.3 Localization and Impact of Signalling Molecules (HL only)3.4.4 Receptor Types and Signal Transduction (HL only)3.4.5 Transmembrane Receptors and Cellular Responses (HL only)3.4.6 Hormone-Receptor Interactions and Cellular Effects (HL only)3.4.7 Intracellular Receptors and Gene Expression (HL only)3.5 Neural Signalling0/03.5.1 Neurons and Their Role in the Nervous System3.5.2 Resting and Action Potentials in Neurons3.5.3 Speed Variations in Nerve Impulse Transmission3.5.4 Synaptic Transmission and Neurotransmitters3.5.5 Action Potential Dynamics (HL only)3.5.6 Advanced Neural Signalling Techniques (HL only)3.5.7 Exogenous Chemicals and Neural Regulation (HL only)3.5.8 Complex Neural Interactions and Consciousness (HL only)3.6 Integration of Body Systems0/03.6.1 System Integration and Coordination3.6.2 Hormonal and Nervous Signalling3.6.3 Central Information Processing3.6.4 Sensory Input and Motor Output3.6.5 Reflex Arcs and Movement Coordination3.6.6 Circadian Rhythms and Hormonal Secretion3.6.7 Endocrine System Control3.6.8 Feedback Mechanisms in Body Regulation3.6.9 Plant Responses and Phytohormones (HL only)3.6.10 Positive Feedback in Plant Processes (HL only)3.7 Defence Against Disease0/03.7.1 Pathogens and Disease3.7.2 Body's Primary Defences3.7.3 Innate vs. Adaptive Immunity3.7.4 Lymphocytes and Antibody Production3.7.5 Immunity and HIV3.7.6 Antibiotics and Resistance3.7.7 Zoonoses and COVID-193.7.8 Vaccines, Herd Immunity, and Pandemics3.8 Populations and Communities0/03.8.1 Population Dynamics3.8.2 Carrying Capacity and Population Control3.8.3 Community Interactions3.8.4 Invasive Species and Competition3.8.5 Predator-Prey Dynamics3.8.6 Allelopathy and Antibiotic Secretion3.9 Transfers of Energy and Matter0/03.9.1 Ecosystems and Energy Sources3.9.2 Autotrophs and Heterotrophs3.9.3 Trophic Levels and Energy Pyramids3.9.4 Energy Loss and Ecosystem Structure3.9.5 The Carbon Cycle3.9.6 Analysis of Carbon Flux3.9.7 Element Recycling in Ecosystems4. Continuity and ChangePremium4.1 DNA Replication0/04.1.1 Basics of DNA Replication4.1.2 DNA Replication Tools & Applications4.1.3 Advanced DNA Replication Processes (HL only)4.1.4 Replication Components in Prokaryotes (HL only)4.1.5 DNA Proofreading and Repair Mechanisms (HL only)4.2 Protein Synthesis0/04.2.1 Transcription Fundamentals4.2.2 Gene Expression4.2.3 Translation Basics4.2.4 Genetic Code Features4.2.5 Translation Process4.2.6 Advanced Transcription and Translation (HL only)4.2.7 Post-transcriptional Modifications (HL only)4.2.8 Protein Modification and Recycling (HL only)4.3 Mutation and Gene Editing0/04.3.1 Types and Consequences of Mutations4.3.2 Causes and Randomness of Mutations4.3.3 Implications of Mutations4.3.4 Gene Knockout Techniques (HL only)4.3.5 CRISPR-Cas9 Technology (HL only)4.3.6 Conserved Genetic Sequences (HL only)4.4 Cell and Nuclear Division0/04.4.1 Generation of New Cells4.4.2 Cytokinesis4.4.3 Roles of Mitosis and Meiosis4.4.4 Chromosome Dynamics4.4.5 Phases of Mitosis4.4.6 Meiosis and Genetic Diversity4.4.7 Cell Proliferation (HL only)4.4.8 Cell Cycle Control (HL only)4.4.9 Tumor Characteristics (HL only)4.5 Gene Expression (HL only)0/04.5.1 Gene Expression Mechanisms (HL only)4.5.2 Regulation of Transcription (HL only)4.5.3 Epigenesis and Differentiation (HL only)4.5.4 Epigenetic Modifications (HL only)4.5.5 Environmental Impacts (HL only)4.6 Water Potential0/04.6.1 Solvation and Water Movement4.6.2 Effects on Plant and Animal Cells4.6.3 Medical and Practical Applications4.6.4 Water Potential Concepts (HL only)4.6.5 Solute and Pressure Potentials (HL only)4.7 Reproduction0/04.7.1 Sexual vs. Asexual Reproduction4.7.2 Human Reproductive Anatomy4.7.3 Fertilization and IVF4.7.4 Plant Reproduction4.7.5 Puberty and Hormonal Control (HL only)4.7.6 Gamete Formation and Fertilization Mechanisms (HL only)4.7.7 Pregnancy and Childbirth (HL only)4.7.8 Hormone Replacement Therapy (HL only)4.8 Inheritance0/04.8.1 Basics of Inheritance4.8.2 Genotype and Phenotype4.8.3 Genetic Disorders and Variations4.8.4 Complex Patterns of Inheritance4.8.5 Pedigree Analysis and Continuous Variation4.8.6 Meiosis and Genetic Diversity (HL only)4.8.7 Gene Mapping and Linkage (HL only)4.8.8 Statistical Analysis in Genetics (HL only)4.9 Homeostasis0/04.9.1 Basics of Homeostasis4.9.2 Negative Feedback in Homeostasis4.9.3 Blood Glucose Regulation and Diabetes4.9.4 Thermoregulation in Humans4.9.5 Kidney Function and Osmoregulation (HL only)4.9.6 Advanced Osmoregulation and Blood Supply Changes (HL only)4.10 Natural Selection0/04.10.1 Evolution and Natural Selection4.10.2 Mutation and Sexual Reproduction4.10.3 Competition and Natural Selection4.10.4 Abiotic Factors and Selection Pressures4.10.5 Adaptation and Fitness4.10.6 Sexual Selection4.10.7 Gene Pools and Allele Frequencies (HL only)4.10.8 Hardy–Weinberg Principle and Artificial Selection (HL only)4.11 Stability and Change0/04.11.1 Ecosystem Stability4.11.2 Requirements for Ecosystem Stability4.11.3 Deforestation and Ecosystem Tipping Points4.11.4 Modeling Ecosystem Stability4.11.5 Keystone Species and Sustainability4.11.6 Pollution and Ecosystem Health4.11.7 Rewilding and Ecosystem Restoration4.11.8 Ecological Succession (HL only)4.12 Climate Change0/04.12.1 Anthropogenic Causes4.12.2 Feedback Cycles and Global Warming4.12.3 Tipping Points in Ecosystems4.12.4 Polar Habitat Changes4.12.5 Oceanic Changes4.12.6 Range Shifts of Species4.12.7 Threats to Coral Reefs4.12.8 Phenology and Climate Change (HL only)4. Continuity and ChangePremium4.1 DNA Replication0/04.1.1 Basics of DNA Replication4.1.2 DNA Replication Tools & Applications4.1.3 Advanced DNA Replication Processes (HL only)4.1.4 Replication Components in Prokaryotes (HL only)4.1.5 DNA Proofreading and Repair Mechanisms (HL only)4.2 Protein Synthesis0/04.2.1 Transcription Fundamentals4.2.2 Gene Expression4.2.3 Translation Basics4.2.4 Genetic Code Features4.2.5 Translation Process4.2.6 Advanced Transcription and Translation (HL only)4.2.7 Post-transcriptional Modifications (HL only)4.2.8 Protein Modification and Recycling (HL only)4.3 Mutation and Gene Editing0/04.3.1 Types and Consequences of Mutations4.3.2 Causes and Randomness of Mutations4.3.3 Implications of Mutations4.3.4 Gene Knockout Techniques (HL only)4.3.5 CRISPR-Cas9 Technology (HL only)4.3.6 Conserved Genetic Sequences (HL only)4.4 Cell and Nuclear Division0/04.4.1 Generation of New Cells4.4.2 Cytokinesis4.4.3 Roles of Mitosis and Meiosis4.4.4 Chromosome Dynamics4.4.5 Phases of Mitosis4.4.6 Meiosis and Genetic Diversity4.4.7 Cell Proliferation (HL only)4.4.8 Cell Cycle Control (HL only)4.4.9 Tumor Characteristics (HL only)4.5 Gene Expression (HL only)0/04.5.1 Gene Expression Mechanisms (HL only)4.5.2 Regulation of Transcription (HL only)4.5.3 Epigenesis and Differentiation (HL only)4.5.4 Epigenetic Modifications (HL only)4.5.5 Environmental Impacts (HL only)4.6 Water Potential0/04.6.1 Solvation and Water Movement4.6.2 Effects on Plant and Animal Cells4.6.3 Medical and Practical Applications4.6.4 Water Potential Concepts (HL only)4.6.5 Solute and Pressure Potentials (HL only)4.7 Reproduction0/04.7.1 Sexual vs. Asexual Reproduction4.7.2 Human Reproductive Anatomy4.7.3 Fertilization and IVF4.7.4 Plant Reproduction4.7.5 Puberty and Hormonal Control (HL only)4.7.6 Gamete Formation and Fertilization Mechanisms (HL only)4.7.7 Pregnancy and Childbirth (HL only)4.7.8 Hormone Replacement Therapy (HL only)4.8 Inheritance0/04.8.1 Basics of Inheritance4.8.2 Genotype and Phenotype4.8.3 Genetic Disorders and Variations4.8.4 Complex Patterns of Inheritance4.8.5 Pedigree Analysis and Continuous Variation4.8.6 Meiosis and Genetic Diversity (HL only)4.8.7 Gene Mapping and Linkage (HL only)4.8.8 Statistical Analysis in Genetics (HL only)4.9 Homeostasis0/04.9.1 Basics of Homeostasis4.9.2 Negative Feedback in Homeostasis4.9.3 Blood Glucose Regulation and Diabetes4.9.4 Thermoregulation in Humans4.9.5 Kidney Function and Osmoregulation (HL only)4.9.6 Advanced Osmoregulation and Blood Supply Changes (HL only)4.10 Natural Selection0/04.10.1 Evolution and Natural Selection4.10.2 Mutation and Sexual Reproduction4.10.3 Competition and Natural Selection4.10.4 Abiotic Factors and Selection Pressures4.10.5 Adaptation and Fitness4.10.6 Sexual Selection4.10.7 Gene Pools and Allele Frequencies (HL only)4.10.8 Hardy–Weinberg Principle and Artificial Selection (HL only)4.11 Stability and Change0/04.11.1 Ecosystem Stability4.11.2 Requirements for Ecosystem Stability4.11.3 Deforestation and Ecosystem Tipping Points4.11.4 Modeling Ecosystem Stability4.11.5 Keystone Species and Sustainability4.11.6 Pollution and Ecosystem Health4.11.7 Rewilding and Ecosystem Restoration4.11.8 Ecological Succession (HL only)4.12 Climate Change0/04.12.1 Anthropogenic Causes4.12.2 Feedback Cycles and Global Warming4.12.3 Tipping Points in Ecosystems4.12.4 Polar Habitat Changes4.12.5 Oceanic Changes4.12.6 Range Shifts of Species4.12.7 Threats to Coral Reefs4.12.8 Phenology and Climate Change (HL only)