A-Level Biology Revision Notes

17 free revision notes covering every main A-Level Biology topic. No account needed.

A-Level Biology contains a great deal of content, but it is not a memorisation subject in the way students expect. The papers reward application — being given an unfamiliar organism, experiment or data set and reasoning about it using principles you know.

That changes how you should revise. Being able to recite the stages of respiration is necessary but not sufficient; the exam is more likely to give you a graph of oxygen uptake and ask you to explain it. Practise applying each process to situations the notes do not cover.

Data and statistics questions are worth substantial marks and are consistently under-prepared. Interpreting a graph, identifying variables and controls, and choosing and justifying a statistical test are all examinable skills in their own right.

Precision of language matters throughout. Mark schemes distinguish sharply between terms that students use interchangeably, and the difference between "diffusion" and "facilitated diffusion" is routinely the difference between a mark and none.

These notes cover molecules, cells, exchange and transport, genetics, energy transfer, homeostasis and ecology.

Biological Molecules

Carbohydrates and Lipids Proteins and Enzymes Nucleic Acids: DNA and RNA

Cell Structure and Division

Eukaryotic and Prokaryotic Cells Mitosis and the Cell Cycle Meiosis and Genetic Variation

Energy Transfers: Respiration and Photosynthesis

Aerobic Respiration Photosynthesis

Exchange and Transport

Transport across Cell Membranes Mass Transport and Gas Exchange

Gene Expression and Regulation

Protein Synthesis: Transcription and Translation

Genetic Information and Variation

Genetic Diversity and Mutation

Genetics, Populations and Evolution

Inheritance and Genetic Crosses Populations and the Hardy-Weinberg Principle

Organisms and the Environment

Energy Transfer and Nutrient Cycles

Response and Homeostasis

Nervous Coordination: Nerve Impulses and Synapses Homeostasis and Negative Feedback

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