biology / Cells & Energy / free
Membrane Transport
Move particles across a membrane and see gradients do the work.
Follow the mechanism1 / 3
A concentration gradient exists. Unequal concentration creates a potential direction for net movement, but it does not guarantee that a molecule can cross.
selective membranepassive diffusion
Transport mode
Focus the idea
gradient68%
permeability58%
directionhigh → low
net flow39
Particles move high → low without ATP. The gradient creates the push; permeability controls how much gets through.
A membrane can be selective and directional: passive transport follows a gradient, while active transport uses ATP to push against it. The particle motion is symbolic, not a molecular-scale simulation.
04 / PRACTICE
0 / 3 checkedMake the biology yours.
Answer from the model, then use the explanation to connect the visual mechanism to the biological rule.
CHECK 1 / 3