Here's a breakdown:
* Concentration: This refers to the amount of a substance in a given volume. A higher concentration means there are more molecules packed together in a certain space.
* Movement: Molecules are in constant motion, randomly bumping into each other.
* Net movement: When there's a concentration difference, the molecules naturally tend to spread out. More molecules move from the area of higher concentration (where they're more crowded) to the area of lower concentration (where they have more space).
Diffusion is a passive process, meaning it doesn't require any energy input. It's fundamental to many biological processes, including:
* Gas exchange in the lungs: Oxygen diffuses from the air in the lungs into the bloodstream, while carbon dioxide diffuses from the blood into the lungs to be exhaled.
* Nutrient absorption in the intestines: Nutrients from digested food diffuse across the walls of the small intestine into the bloodstream.
* Waste removal in the kidneys: Waste products from the blood diffuse into the urine in the kidneys.
Let me know if you have any more questions about diffusion!
