Edexcel · IGCSE
Your journey to excellence inHuman Biology
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Start with the first Human Biology lesson.
Cell Structures Under a Light Microscope
1Cell Structures Under a Light MicroscopeRead next2Cell Structures Under an Electron MicroscopeRead next3The Nucleus and Its FunctionRead next4Chromosomes and Their RoleRead next5Cell Membrane Structure and FunctionRead next6Mitochondria and Energy ProductionRead next7Endoplasmic Reticulum and Protein TransportRead next8Ribosomes and Protein SynthesisRead next9DNA Double Helix StructureRead next10Nucleotides and Base PairingRead next11Hydrogen Bonds in DNARead next12Process of DNA ReplicationRead next13Role of DNA Polymerase in ReplicationRead next14Genes and Their Role in Protein CodingRead next15Codons and Amino AcidsRead next16RNA Structure and Differences from DNARead next17Role of RNA in Protein SynthesisRead next18DNA Mutations and Their EffectsRead next19Transcription: Formation of mRNARead next20Translation: mRNA to PolypeptidesRead next21tRNA and Codon-Anticodon InteractionRead next22Genetic Engineering PrinciplesRead next23Genetically Modified Bacteria for Insulin ProductionRead next24Genetically Modified Plants for Vaccines and NutritionRead next25Mitosis: Growth and RepairRead next26Stages of Mitosis: Prophase to TelophaseRead next27Diploid Daughter Cells in MitosisRead next28Embryonic vs Adult Stem CellsRead next29Ethics of Stem Cell ResearchRead next30Organisation of Cells into TissuesRead next31Tissues Organised into OrgansRead next32Structure of Bone TissueRead next33Structure of Muscle TissueRead next34Structure of Blood TissueRead next35Structure of Nervous TissueRead next36Epithelium: Squamous and Ciliated CellsRead next37Specialised Reproductive Cells: SpermRead next38Specialised Reproductive Cells: Egg (Ovum)Read next39Adaptations of Sperm for FertilisationRead next40Adaptations of Egg for FertilisationRead next
Elements in Biological Molecules
1Elements in Biological MoleculesRead next2Structure of CarbohydratesRead next3Structure of ProteinsRead next4Structure of LipidsRead next5Formation of Starch and GlycogenRead next6Formation of Proteins from Amino AcidsRead next7Formation of Lipids from Fatty Acids and GlycerolRead next8Testing for Glucose (Reducing Sugar)Read next9Testing for StarchRead next10Testing for LipidsRead next11Testing for ProteinsRead next12Practical: Vitamin C Content in FoodRead next13Practical: Measuring Energy Content in FoodRead next14Enzymes as Biological CatalystsRead next15Mechanism of Enzyme ActionRead next16Effect of Temperature on Enzyme ActivityRead next17Effect of pH on Enzyme ActivityRead next18Effect of Substrate Concentration on Enzyme ActivityRead next19Competitive Inhibitors of EnzymesRead next20Non-Competitive Inhibitors of EnzymesRead next21Practical: Investigating Temperature Effects on EnzymesRead next22Practical: Investigating pH Effects on EnzymesRead next23Advantages of Immobilised EnzymesRead next24Immobilised Enzymes in Lactose-Free Milk ProductionRead next25Immobilised Enzymes in Sucrose ConversionRead next26Immobilised Enzymes in Glucose Testing StripsRead next27Practical: Preparing Alginate Beads for Immobilised EnzymesRead next28Practical: Investigating Immobilised Enzyme ActivityRead next
Definition of Diffusion
1Definition of DiffusionRead next2Definition of OsmosisRead next3Definition of Active TransportRead next4Key Differences: Diffusion, Osmosis, Active TransportRead next5Understanding Water Potential in OsmosisRead next6The Role of Cell Membranes in Substance MovementRead next7Factors Affecting Diffusion RatesRead next8Factors Affecting Osmosis RatesRead next9Factors Affecting Active Transport RatesRead next10Surface Area to Volume Ratio and Substance MovementRead next11Temperature's Effect on Substance MovementRead next12Concentration Gradient and Its Impact on DiffusionRead next13Energy Requirements for Active TransportRead next14Examples of Diffusion in Human BiologyRead next15Examples of Osmosis in Human BiologyRead next16Examples of Active Transport in Human BiologyRead next17Practical: Investigating Diffusion with Non-Living SystemsRead next18Practical: Investigating Osmosis in Living SystemsRead next19Practical: Investigating Osmosis Using Visking TubingRead next20Practical: Investigating Active Transport in Plant RootsRead next21Adaptations of Cells for Efficient DiffusionRead next22Adaptations of Cells for OsmosisRead next23Adaptations of Cells for Active TransportRead next24The Role of Protein Channels in Active TransportRead next25The Role of Carrier Proteins in Active TransportRead next26Diffusion Across the Alveoli in Gas ExchangeRead next27Osmosis in Kidney Function and Urine ConcentrationRead next28Active Transport in Nutrient Absorption in the GutRead next29Exam Trap: Misinterpreting Diffusion and OsmosisRead next30Exam Trap: Confusing Passive and Active TransportRead next31Mathematical Skills: Calculating Rates of DiffusionRead next32Mathematical Skills: Surface Area to Volume RatioRead next33Interpreting Graphs of Diffusion and Osmosis RatesRead next34Role of ATP in Active TransportRead next35The Sodium-Potassium Pump as an Active Transport ExampleRead next36Endocytosis and Exocytosis as Bulk Transport MechanismsRead next37The Importance of Maintaining Concentration GradientsRead next38Impact of Cell Size on Diffusion EfficiencyRead next39Practical: Investigating Factors Affecting Diffusion RatesRead next40Practical: Investigating Temperature and OsmosisRead next41Practical: Investigating Surface Area and DiffusionRead next42Role of Aquaporins in OsmosisRead next43Transport of Ions in Nerve Cells via Active TransportRead next44Transport of Glucose in the Small IntestineRead next45Diffusion in the Movement of Carbon Dioxide in RespirationRead next46Osmosis in Plant Cells and Turgor PressureRead next47Impact of Hypotonic, Hypertonic, and Isotonic SolutionsRead next48Practical: Investigating Turgidity in Plant CellsRead next49Common Misconceptions About Osmosis and DiffusionRead next50Linking Diffusion, Osmosis, and Active Transport to HomeostasisRead next
Functions of the Axial Skeleton
1Functions of the Axial SkeletonRead next2Functions of the Appendicular SkeletonRead next3Structure of a Long BoneRead next4Compact and Spongy Bone DistributionRead next5Epiphysis and Its Role in BonesRead next6Structure of a Synovial JointRead next7Functions of Synovial JointsRead next8The Elbow Joint Structure and FunctionRead next9The Shoulder Joint Structure and FunctionRead next10Cartilaginous Intervertebral JointsRead next11Voluntary Muscles and MovementRead next12Biceps and Triceps in Arm MovementRead next13Bone-Muscle Interactions in MovementRead next14Dietary Factors for Bone HealthRead next15Dietary Factors for Muscle HealthRead next16Calcium and Bone DevelopmentRead next17Vitamin D and Bone HealthRead next18Protein and Muscle MaintenanceRead next19Causes of OsteoporosisRead next20Symptoms of OsteoporosisRead next21Prevention of OsteoporosisRead next22The Role of Exercise in Bone HealthRead next23The Role of Exercise in Muscle StrengthRead next24Common Injuries to Bones and JointsRead next25Healing Process of Bone FracturesRead next26Ligaments and Their Role in JointsRead next27Tendons and Their Role in MovementRead next28Cartilage and Its Function in JointsRead next29Synovial Fluid and Joint LubricationRead next30Structure of Voluntary Muscle FibersRead next31Structure of Involuntary Muscle FibersRead next32Structure of Cardiac Muscle FibersRead next33Comparison of Muscle TypesRead next34Antagonistic Muscle PairsRead next35Role of Nerves in Muscle ContractionRead next36Microscopic Structure of Skeletal MuscleRead next37Practical: Observing Bone and Muscle TissueRead next38Practical: Investigating Joint MovementRead next39Practical: Effect of Diet on Bone StrengthRead next40Practical: Testing Muscle FatigueRead next41Exam Trap: Confusing Ligaments and TendonsRead next42Exam Trap: Misinterpreting Joint TypesRead next43Exam Trap: Osteoporosis Risk FactorsRead next
Structure of Sensory, Motor, and Relay Neurones
1Structure of Sensory, Motor, and Relay NeuronesRead next2Functions of Sensory, Motor, and Relay NeuronesRead next3Central Nervous System OverviewRead next4Main Areas of the Brain and Their FunctionsRead next5Structure and Functions of the Spinal CordRead next6Structure of a Reflex ArcRead next7Receptors for Light, Temperature, Pressure, and TasteRead next8Pathway of a Nerve Impulse to a StimulusRead next9Investigating Sensory Receptors in SkinRead next10Initiation and Transmission of Nerve ImpulsesRead next11Transmission Across a SynapseRead next12Pituitary Gland Hormones: ADH and Gonadotrophic HormonesRead next13Adrenal Gland Hormone: AdrenalineRead next14Thyroid Gland HormonesRead next15Pancreatic Hormones: Insulin and GlucagonRead next16Gonadal Hormones and Their RolesRead next17Comparison of Nervous and Hormonal SystemsRead next18Structure and Function of the EyeRead next19Focusing on Near and Distant ObjectsRead next20Eye Response to Light Intensity ChangesRead next21Stereoscopic Vision and Depth PerceptionRead next22Eye Defects: Long Sight, Short Sight, and AstigmatismRead next23Cataracts and Corneal TransplantsRead next24Structure and Function of the Ear in HearingRead next25Structure and Function of the Ear in BalanceRead next26Effects of Prolonged Noise Exposure on HearingRead next27Investigating the Range of Audible FrequenciesRead next28Definition and Types of DrugsRead next29Legal and Illegal Drugs: Examples and EffectsRead next30Effects of Heroin, Cannabis, and CocaineRead next31Action of Painkillers on the Nervous SystemRead next32Effects of Alcohol on the Nervous System and LiverRead next33Behavioural Consequences of Alcohol ConsumptionRead next34Causes, Symptoms, and Treatments of SchizophreniaRead next35Causes, Symptoms, and Treatments of DepressionRead next36Causes, Symptoms, and Treatments of Alzheimer’s DiseaseRead next37Causes, Symptoms, and Treatments of Vascular DementiaRead next38Causes, Symptoms, and Treatments of Parkinson’s DiseaseRead next
What is a Balanced Diet?
1What is a Balanced Diet?Read next2Components of a Balanced DietRead next3Sources of Carbohydrates in DietRead next4Functions of Carbohydrates in the BodyRead next5Sources of Proteins in DietRead next6Functions of Proteins in the BodyRead next7Sources of Lipids (Fats and Oils)Read next8Functions of Lipids in the BodyRead next9Sources and Functions of Vitamin ARead next10Sources and Functions of Vitamin CRead next11Sources and Functions of Vitamin DRead next12Sources and Functions of CalciumRead next13Sources and Functions of IronRead next14Role of Dietary Fibre in DigestionRead next15Dietary Variations by Age and PregnancyRead next16Dietary Variations by Climate and OccupationRead next17Deficiency Diseases: Scurvy and Vitamin CRead next18Deficiency Diseases: Anaemia and IronRead next19Deficiency Diseases: Blindness and Vitamin ARead next20Deficiency Diseases: Kwashiorkor and ProteinRead next21Structure of the Human Alimentary CanalRead next22Functions of the Mouth and OesophagusRead next23Functions of the Stomach in DigestionRead next24Functions of the Small Intestine in DigestionRead next25Functions of the Large Intestine in DigestionRead next26Role of the Pancreas in DigestionRead next27Peristalsis and the Role of FibreRead next28Digestive Enzymes: Amylase and MaltaseRead next29Digestive Enzymes: Proteases (Pepsin and Trypsin)Read next30Digestive Enzymes: LipasesRead next31Production and Functions of BileRead next32Bile and Lipid EmulsificationRead next33Structure of the Villus in AbsorptionRead next34Adaptations of the Villus for AbsorptionRead next35Types and Structure of Human TeethRead next36Factors Affecting Tooth GrowthRead next37How to Care for Teeth and GumsRead next38Understanding Body Mass Index (BMI)Read next39Calculating BMI Step-by-StepRead next40Obesity and Risk of DiabetesRead next41High Cholesterol and AtherosclerosisRead next42Hygienic Food Preparation PracticesRead next43Safe Methods of Cooking FoodRead next44Food Storage and Preservation TechniquesRead next
Definition of Respiration
1Definition of RespirationRead next2Aerobic Respiration Word EquationRead next3Aerobic Respiration Chemical EquationRead next4Anaerobic Respiration Word EquationRead next5Aerobic vs Anaerobic RespirationRead next6Energy Release in RespirationRead next7Role of ATP in Energy TransferRead next8ATP Phosphate Group AdditionRead next9ATP Phosphate Group RemovalRead next10Inspired Air CompositionRead next11Expired Air CompositionRead next12Carbon Dioxide Levels in Inspired vs Expired AirRead next13Practical: Investigating Carbon Dioxide in AirRead next14Oxygen Levels in Inspired vs Expired AirRead next15Nitrogen Levels in Inspired vs Expired AirRead next16Water Vapour in Inspired vs Expired AirRead next17Heat Energy in Expired AirRead next18Respiration in Living OrganismsRead next19Respiration in Plants vs AnimalsRead next20Cellular Location of Aerobic RespirationRead next21Cellular Location of Anaerobic RespirationRead next22Mitochondria and RespirationRead next23Enzymes in RespirationRead next24Glucose Breakdown in RespirationRead next25Oxygen's Role in Aerobic RespirationRead next26Lactic Acid Formation in Anaerobic RespirationRead next27Energy Yield: Aerobic vs Anaerobic RespirationRead next28Respiration During ExerciseRead next29Oxygen Debt After ExerciseRead next30Respiration and Muscle FatigueRead next31Respiration and Heat ProductionRead next32Respiration in MicroorganismsRead next33Practical: Measuring Respiration RateRead next34Respiration and Metabolic ProcessesRead next35Respiration in Different CellsRead next36Factors Affecting Respiration RateRead next37Respiration and Energy StorageRead next38Respiration and ATP RecyclingRead next39Common Misconceptions About RespirationRead next40Exam Trap: Misinterpreting Respiration EquationsRead next41Exam Trap: Confusing Aerobic and Anaerobic RespirationRead next
Structure of the Thorax
1Structure of the ThoraxRead next2Ribs and Intercostal MusclesRead next3Diaphragm Function in BreathingRead next4Trachea and Bronchi StructureRead next5Bronchioles and AlveoliRead next6Pleural Membranes and Their RoleRead next7Mechanics of Lung VentilationRead next8Role of Intercostal Muscles in VentilationRead next9Role of the Diaphragm in VentilationRead next10Gas Exchange in the AlveoliRead next11Adaptations of Alveoli for DiffusionRead next12Surface Area in Gas ExchangeRead next13Blood Capillaries Around AlveoliRead next14Oxygen and Carbon Dioxide TransportRead next15Lung Capacity and Spirometer TracesRead next16Understanding Vital CapacityRead next17Tidal Volume and Its MeasurementRead next18Interpreting Spirometer GraphsRead next19Practical: Investigating Lung CapacityRead next20Effects of Exercise on Breathing RateRead next21Practical: Measuring Breathing Rate During ExerciseRead next22Carbon Dioxide Regulation in BloodRead next23Role of Chemoreceptors in Breathing ControlRead next24Aerobic Exercise and Breathing EfficiencyRead next25Long-Term Benefits of Exercise on LungsRead next26Pulse Rate as a Fitness IndicatorRead next27Heart Rate Changes During ExerciseRead next28Influence of Adrenaline on Heart RateRead next29Practical: Investigating Pulse Rate After ExerciseRead next30Oxygen Debt After ExerciseRead next31Mechanism of Oxygen Debt RepaymentRead next32Smoking and Respiratory System DamageRead next33Smoking Effects on Cardiovascular HealthRead next
Composition of Blood
1Composition of BloodRead next2Role of Plasma in TransportRead next3Tissue Fluid Formation and DrainageRead next4Adaptations of Red Blood CellsRead next5ABO Blood Groups and TransfusionsRead next6Functions of White Blood CellsRead next7Phagocytosis ProcessRead next8Antibody Production by LymphocytesRead next9Blood Clotting MechanismRead next10Role of Fibrin in ClottingRead next11Structure of ArteriesRead next12Structure of VeinsRead next13Structure of CapillariesRead next14Comparison of Blood VesselsRead next15Pulse and Blood FlowRead next16Circulatory System PathwayRead next17Blood Vessels of the HeartRead next18Blood Vessels of the LungsRead next19Blood Vessels of the LiverRead next20Blood Vessels of the KidneysRead next21Heart Structure OverviewRead next22Heart Function and Blood FlowRead next23Causes of Heart DiseaseRead next24Diet and Exercise in Heart HealthRead next25Use of Stents in Heart DiseaseRead next26Artificial Hearts and TransplantsRead next27Problems with Heart TransplantsRead next28Role of Statins in Heart HealthRead next29Plant Stanol Esters in TreatmentRead next30Beta-Blockers in Circulatory DisordersRead next31Systolic and Diastolic Blood PressureRead next32Causes of HypertensionRead next33Prevention of HypertensionRead next34Treatment of HypertensionRead next35ACE Inhibitors in Blood Pressure ControlRead next36Production of Monoclonal AntibodiesRead next37Detection of Diseases with AntibodiesRead next38Treatment of Cancer with AntibodiesRead next
Definition of Homeostasis
1Definition of HomeostasisRead next2Examples of Homeostatic ProcessesRead next3The Concept of Negative FeedbackRead next4Structure and Functions of the SkinRead next5Role of Sweat Glands in Temperature RegulationRead next6Vasodilation and Heat LossRead next7Vasoconstriction and Heat RetentionRead next8Role of Shivering in Temperature RegulationRead next9Definition of ExcretionRead next10Metabolic Waste Products: Urea, CO2, and WaterRead next11Structure of the Renal SystemRead next12Functions of the KidneysRead next13Formation of Urine in the NephronsRead next14Selective Reabsorption in the KidneysRead next15How Urine Composition VariesRead next16Role of the Hypothalamus in OsmoregulationRead next17Role of the Pituitary Gland in OsmoregulationRead next18Mechanism of ADH in Water RegulationRead next19Osmoregulation and Negative FeedbackRead next20Roles of Insulin and Glucagon in Blood Glucose ControlRead next21Blood Glucose Regulation and Negative FeedbackRead next22Functions of the Liver in HomeostasisRead next23Liver's Role in Bile ProductionRead next24Liver's Role in Blood Sugar RegulationRead next25Liver's Role in Urea FormationRead next26Liver's Role in DetoxificationRead next27Breakdown of Alcohol in the LiverRead next28Advantages and Disadvantages of Kidney DialysisRead next29How Dialysis Mimics Kidney FunctionRead next30Advantages and Disadvantages of Kidney TransplantsRead next31Temperature Regulation in Different EnvironmentsRead next32Practical: Investigating Diffusion with Visking TubingRead next33Examining the Role of ADH in Different ConditionsRead next34Common Misconceptions about Negative FeedbackRead next35Impact of Lifestyle on Homeostatic MechanismsRead next36Diseases Affecting Kidney FunctionRead next37Understanding Diabetes and Its Effect on Blood Glucose RegulationRead next38The Role of Hormones in HomeostasisRead next39Practical: Investigating the Effect of Temperature on Enzyme ActivityRead next40The Importance of Homeostasis for SurvivalRead next41How the Body Responds to DehydrationRead next42The Role of the Hypothalamus in Temperature RegulationRead next43Case Study: Homeostasis in Extreme ConditionsRead next44Exam Trap: Misinterpreting Negative Feedback LoopsRead next
The Process of Fertilisation
1The Process of FertilisationRead next2Formation of a Zygote to EmbryoRead next3Stages of Meiosis and Gamete ProductionRead next4Significance of Meiosis in VariationRead next5Structure of the Male Reproductive SystemRead next6Structure of the Female Reproductive SystemRead next7Functions of the Male Reproductive OrgansRead next8Functions of the Female Reproductive OrgansRead next9Roles of Oestrogen and ProgesteroneRead next10Roles of FSH and LH in the Menstrual CycleRead next11Role of Progesterone in PregnancyRead next12Functions of the Placenta in PregnancyRead next13Role of Amniotic Fluid in PregnancyRead next14Function of the Umbilical CordRead next15Oestrogen and Testosterone in PubertyRead next16Development of Secondary Sexual CharacteristicsRead next17The Birth ProcessRead next18Advantages of BreastfeedingRead next19Human Growth and Development StagesRead next20Interpreting Human Growth CurvesRead next21Hormonal Methods of ContraceptionRead next22Barrier Methods of ContraceptionRead next23Natural Methods of ContraceptionRead next24Intra-Uterine Devices and SterilisationRead next25Advantages and Disadvantages of Contraceptive MethodsRead next26The Process of IVFRead next27Benefits and Challenges of IVFRead next28Genes and Alleles: Definitions and RolesRead next29Dominant and Recessive AllelesRead next30Homozygous and Heterozygous TraitsRead next31Phenotype and Genotype ExplainedRead next32Co-Dominance in Genetic TraitsRead next33Diploid and Haploid CellsRead next34Chromosomal Basis of Sex DeterminationRead next35Using Genetic Diagrams to Predict Offspring SexRead next36Random Fertilisation and Genetic VariationRead next37Multiple Alleles and ABO Blood GroupsRead next38Understanding Monohybrid InheritanceRead next39Constructing Genetic Diagrams for Monohybrid InheritanceRead next40Interpreting Family PedigreesRead next41Causes of Haemophilia and Red-Green Colour BlindnessRead next42Sex-Linked Inheritance PatternsRead next43Polydactyly: Causes and EffectsRead next44Cystic Fibrosis: Causes and InheritanceRead next45Gene Therapy for Cystic FibrosisRead next46Genetic vs Environmental VariationRead next47Combination of Genetic and Environmental Factors in VariationRead next
Definition of Disease Stages
1Definition of Disease StagesRead next2Understanding PathogensRead next3Structure of VirusesRead next4Reproduction of VirusesRead next5Transmission and Prevention of HIVRead next6Transmission and Prevention of EbolaRead next7Structure of BacteriaRead next8Nutrition in BacteriaRead next9Reproduction of BacteriaRead next10Understanding Bacterial Growth CurvesRead next11Effects of Antibacterial AgentsRead next12Effects of Antibiotics on BacteriaRead next13Transmission and Prevention of CholeraRead next14Transmission and Prevention of GonorrhoeaRead next15Importance of Oral Rehydration TherapyRead next16Transmission and Prevention of Athlete's FootRead next17Role of Mosquitoes in Malaria TransmissionRead next18Role of Houseflies in Typhoid TransmissionRead next19Treatment and Prevention of MalariaRead next20Treatment and Prevention of TyphoidRead next21Understanding the Antibody-Antigen ReactionRead next22How Vaccines Prevent DiseaseRead next23Natural vs Artificial ImmunityRead next24Active vs Passive ImmunityRead next25Sources of AntibioticsRead next26Role of Antibiotics in Treating DiseaseRead next27How Resistant Pathogens AriseRead next28Concerns About Antibiotic Resistance (e.g., MRSA)Read next29Role of Decomposers in Organic Matter BreakdownRead next30Non-Pathogenic Bacteria Useful to HumansRead next31Role of Fungi in DecompositionRead next32Processes in Modern Sewage TreatmentRead next33Role of Aerobic Microorganisms in Sewage BreakdownRead next34Role of Anaerobic Microorganisms in Sewage BreakdownRead next35Understanding Pit LatrinesRead next