What is the process of diffusion in cells?
Diffusion is the passive movement of molecules from a region of higher concentration to a region of lower concentration until equilibrium is reached.
It is a fundamental transport mechanism in cells and does not require energy (ATP).
Process of diffusion in cells:
1. Concentration gradient
Diffusion occurs due to a difference in concentration across the cell membrane.
2. Movement of molecules
Molecules move randomly but overall shift from an area of higher concentration to lower concentration.
3. Crossing the cell membrane
Small and non-polar molecules (like oxygen and carbon dioxide) pass directly through the phospholipid bilayer.
4. Equilibrium
Diffusion continues until the concentration of molecules is evenly distributed on both sides of the membrane.
Factors affecting diffusion:
Concentration gradient (greater difference → faster diffusion)
Temperature (higher temperature → faster movement)
Surface area (larger area → more diffusion)
Size of molecules (smaller molecules diffuse faster)
Importance in cells:
Helps in gas exchange (O₂ and CO₂)
Assists in nutrient transport
Maintains cellular balance
Examples:
Oxygen entering cells from blood
Carbon dioxide leaving cells into blood
In simple terms: Diffusion is the natural movement of molecules from high to low concentration without using energy.