Learn: Diffusion in Biology

Welcome!Today we'll learn about diffusion, a key process in biology. This lesson will help you understand how substances move and why it's important for living organisms.

What is Diffusion?Diffusion is the movement of particles from an area of high concentration to an area of low concentration. It happens because particles are constantly moving and spreading out. This process is vital for cells, as it allows substances like oxygen and nutrients to enter and waste products to leave.

Where Does Diffusion Happen?Diffusion occurs across cell membranes when particles move in or out of cells. For example, oxygen diffuses into cells for respiration, while carbon dioxide diffuses out as a waste product. The process does not require energy, which makes it a type of passive transport.

Factors Affecting DiffusionThe rate of diffusion depends on several factors: concentration gradient (the difference in concentration), temperature (higher temperature makes particles move faster), and the surface area available for diffusion.

Diffusion in the LungsIn the lungs, diffusion allows oxygen to move from the air in the alveoli (high concentration) into the blood (low concentration). At the same time, carbon dioxide moves from the blood into the alveoli to be exhaled.

Review Time!Great work! You've learned about diffusion, factors affecting its rate, and examples like how it works in the lungs. Now let's test your understanding with a few questions.