Guides · Biology + Chemistry
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Every guide explains one idea step by step, in plain words, and links to the tool or chart that goes with it. Follow a path from the start, or jump straight to what you need.
01 · START HERE
Two paths for beginners.
New to a field? Read these in order. Each guide builds on the one before it.
Biology foundations
4 GUIDESChemistry foundations
4 GUIDES02 · ALL GUIDES
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Showing 16 of 16 guides
- Biology Beginner
Cells and organelles
The parts of a cell and what each one does.
+ ChartRead guide → - Biology Beginner
DNA, genes and heredity
How traits are stored, copied and passed on.
Read guide → - Biology Beginner
Mitosis and meiosis
Two ways a cell divides, and why both are needed.
Read guide → - Biology Beginner
Photosynthesis
How plants turn light, water and carbon dioxide into sugar.
+ ChartRead guide → - Biology Intermediate
Cellular respiration
How cells release energy from glucose, stage by stage.
Read guide → - Biology Intermediate
Protein synthesis
From a DNA sequence to a finished chain of amino acids.
+ ToolRead guide → - Biology Intermediate
Enzymes
How enzymes speed up reactions and what slows them down.
+ ChartRead guide → - Biology Beginner
Evolution by natural selection
How populations change over generations.
Read guide → - Chemistry Beginner
Atomic structure
Protons, neutrons and electrons, and how they are arranged.
Read guide → - Chemistry Beginner
Reading the periodic table
What groups, periods and blocks tell you about an element.
+ ToolRead guide → - Chemistry Beginner
Chemical bonding
Ionic, covalent and metallic bonds, and how to tell them apart.
Read guide → - Chemistry Beginner
Moles and molar mass
Counting atoms by weighing them, with worked examples.
+ ToolRead guide → - Chemistry Beginner
Acids, bases and pH
What pH measures and how to calculate it.
+ Tool+ ChartRead guide → - Chemistry Beginner
Balancing chemical equations
A reliable method for making both sides match.
Read guide → - Chemistry Intermediate
Molarity and dilutions
Concentration, and how to prepare a solution from stock.
+ ToolRead guide → - Chemistry Intermediate
Reaction rates and equilibrium
Why reactions speed up, slow down and settle.
+ ChartRead guide →
Questions about the guides
- Most guides are pitched at GCSE / A-level (UK) or equivalent high-school science (US grades 9–12). Intermediate guides go one step further and cover first-year university topics. They align broadly with the AQA Science specifications and US Next Generation Science Standards (NGSS).
- Each guide is written against primary sources and cross-checked. The main biology references are NCBI Bookshelf (including Molecular Biology of the Cell by Alberts et al.) and the Nature Scitable library.
- All numerical values cite their source. Atomic weights follow IUPAC 2021; thermodynamic and reaction data follow NIST Chemistry WebBook; biological constants cite BioNumbers (Harvard).
- Yes, but always check the guide content against your own syllabus and textbook — exam boards vary. Cross-reference with your official specification from AQA, OCR, Edexcel, or College Board (AP).
- Use the "Request a guide" link at the bottom of this page. All requests are reviewed and the most-requested topics are added first. You can also browse what other open-science projects are covering at CK-12 Foundation or OpenStax.
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