Why larger organisms need transport systems
Why larger organisms need transport systems
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient. Tiny unicellular organisms such as Amoeba can rely on it because their surface area to volume ratio is large and the diffusion distance to the centre is short.
Step-by-step lessons on Edexcel IGCSE Biology Transport. Each one builds up to exam-style questions. Start with the foundational cell biology and core content before moving on to the more data-heavy ecology, genetics and practical-skills topics, which carry a large share of the exam marks.