SL IB Biology Revision Notes 2025

Syllabus Edition

First teaching 2023

First exams 2025

Form & Function

Properties of Carbon

Macromolecules

Carbohydrates: Definition, Functions & Examples

Role of Glycoproteins

Lipids

Fatty Acids

Phospholipids

Formation of Proteins

The Variety of Proteins

Protein Structure: Effect of pH & Temperature

Lipid Bilayers

Membrane Proteins

Membrane Transport

Glycolipids & Glycoproteins

The Fluid Mosaic Model: Skills

Cell Organelles

Cell Compartmentalisation

Stem Cells

Cell Specialisation

Gas Exchange in Organisms

Mammalian Lungs: Adaptations

Mechanism of Ventilation

Measuring Lung Volumes: Skills

Gas Exchange in Plants

Drawing Leaf Structure: Skills

Determining Stomatal Density: Skills

Blood Vessels

Identify Blood Vessels: Skills

Measuring Pulse Rate: Skills

Coronary Heart Disease: Skills

The Transpiration Stream

Adaptations of Xylem Vessels

Drawing Root & Stem Structure: Skills

Habitats

Abiotic Factors & Species Distribution

Species Distribution: Skills

Abiotic Factors: Marine & Terrestrial

Biomes

Ecological Niches

Methods of Nutrition

Nutrition in Hominidae: Skills

Nutrition: Adaptations of Organisms

Competition Between Species

Interaction & Interdependence

Metabolism: Enzymes & Reactions

Enzyme Action

Enzyme Activity: Skills

Enzyme Reaction Rates: Skills

Activation Energy: Skills

Adenosine Triphosphate (ATP)

Cell Respiration

Cell Respiration: Skills

The Process of Photosynthesis

Separating Photosynthetic Pigments: Skills

Absorption Spectra

Absorption & Action Spectra: Skills

Limiting Factors of Photosynthesis: Skills

Carbon Dioxide Enrichment Experiments

Neurones: Function & Structure

Nerve Impulses

Nerve Impulses: Skills

Synapses

Integration in Living Organisms

The Nervous System

Reflex Arc & Movement Control

Epinephrine & Melatonin

Control Mechanisms

Pathogens

Barriers to Pathogens: Skin & Mucous Membranes

Blood Clotting

The Immune System

White Blood Cells

Adaptive Immune Response

HIV & AIDS

Antibiotics

Antibiotic Resistance

Zoonoses

Vaccines & Immunity

Evaluating COVID-19 Data: Skills

Populations in Ecosystems

Estimating Population Size

Limiting Population Size

Limiting Population Size: Examples

Population Growth Curves: Skills

Populations: Intraspecific Relationships

Community: Interspecific Relationships

Interspecific Competition

Chi-Squared Test: Skills

Ecosystems as Open Systems

Energy Flow in Ecosystems

Obtaining Carbon Compounds in Ecosystems

Trophic Levels

Pyramids of Energy: Skills

Energy Losses

Primary & Secondary Production

The Carbon Cycle

Nutrient Cycling

Continuity & Change

DNA Replication

Electrophoresis & PCR

Electrophoresis & PCR: Applications

Transcription in Protein Synthesis

Translation in Protein Synthesis

The Genetic Code

Protein Structure & Mutations

Gene Mutations

Consequences of Gene Mutations

Mutations & Genetic Variation

Sexual & Asexual Reproduction

Seed Dispersal & Germination

Genetic Inheritance & Genetic Crossing

Inheritance: Terminology

Inheriting Alleles

Sex Determination

Pedigree Charts

Continuous Variation: Skills

Homeostasis: Maintaining the Internal Environment

Regulation of Blood Glucose

Thermoregulation

Natural Selection & Evolution

Selection Pressures

Selection Pressures: Skills

Stability in Ecosystems

Ecosystem Stability: Skills

Keystone Species

Sustainability in Ecosystems & Agriculture

Eutrophication

The Effects of Pollution

Restoring Ecosystems

Causes of Climate Change

Impact of Climate Change

Carbon Sequestration

Tools

Safety, Ethical & Environmental Issues in Biology (HL)

Measuring Variables in Biology

Applying Techniques in Biology

Applying Technology to Collect Data in Biology

Applying Technology to Process Data in Biology

Applying General Mathematics in Biology

Using Units, Symbols & Numerical Values in Biology

Processing Uncertainties in Biology

Graphing in Biology

Study tools

SL IB Biology Revision Notes

Unity & Diversity

Form & Function

Interaction & Interdependence

Continuity & Change

Tools