What is diffusion?
In GCSE biology, diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration. This movement is said to occur down a concentration gradient. When particles move by diffusion, the process continues until they are evenly distributed.
Diffusion can involve particles of a gas or particles in a solution. It is passive, meaning that it does not require energy to take place.
Diffusion can take place across cell membranes in living organisms, e.g. oxygen diffuses into the blood during gas exchange, and urea diffuses out of the blood during excretion.
Diffusion revision resources to ace your exams
You can explore diffusion further using our GCSE revision notes, topic questions and flashcards for your specific exam board:
Meet all your GCSE biology revision needs using our revision resources linked below. This includes revision notes, videos, flashcards and exam questions with student-friendly mark schemes.
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