Membrane Transport Rate Simulator
Compare the rate of transport across a membrane based on concentration gradients, carrier proteins, and ATP availability.
About this simulation
- What
- An interactive Biology simulation of Membrane Transport Rate Simulator.
- Who
- Designed for AP, IB, and A‑Level Biology students.
- How
- Runs in any modern browser — drag, adjust, and explore in real time.
Updated 2025-10-03
Key Concepts
Simple Diffusion
Movement of molecules from high to low concentration. Rate is strictly proportional to the concentration gradient.
Facilitated Diffusion
Passive transport aided by carrier proteins. Exhibits saturation kinetics (a maximum Vmax rate) when all carriers are busy.
Active Transport
Moves molecules against their gradient (low to high). Requires ATP energy and specific pump proteins.
Understanding Transport Rates
The rate at which substances cross the cell membrane is crucial for cellular homeostasis. Different distinct mechanisms yield entirely different rate curves when plotted against concentration.
Simple diffusion follows a linear path: the steeper the gradient, the faster the rate. However, any carrier-mediated transport (like facilitated diffusion) will eventually plateau at a maximum rate (Vmax) because proteins become saturated.
Use the sliders to adjust initial concentrations and observe how the different transport mechanisms respond dynamically.