Passive transport — Science definition
Movement of substances across the membrane down their concentration gradient, requiring no energy from the cell.
Where it is taught
- Cellular Transport — Cells, Membranes & Exchange, Life Science: Biology, Grade 10
In use
In passive transport, substances drift across on their own, moving down a concentration gradient — from where they are crowded to where they are sparse — and no additional cellular energy supply is required for that passive transfer.
Cellular Transport
Questions using passive transport
Problem 1
Which is TRUE of active transport but NOT of passive transport?
- It never uses proteins
- It only moves water
- It requires energy (ATP) and can move substances against their concentration gradient
- It moves substances down their concentration gradient
Answer and explanation
It requires energy (ATP) and can move substances against their concentration gradient
Active transport spends energy to move substances against the gradient; passive transport moves them down the gradient for free.