Why diffusion alone is not enough
Why diffusion alone is not enough
Every living cell needs oxygen and nutrients for metabolism and must remove wastes such as carbon dioxide. Small organisms can often rely on diffusion because most cells are close to the outside environment.
Step-by-step lessons on Edexcel A A Level Biology Circulatory system and mass transport. Each one builds up to exam-style questions. Build a strong foundation in cell biology and biochemistry early on, since later topics on genetics, ecology and physiology all draw on these core concepts.