Active Transport

Real World Example

Imagine trying to push a heavy shopping cart uphill at the grocery store parking lot. Just as you need to exert effort and energy to move the cart against gravity, cells use energy to transport materials across their membranes against a concentration gradient. In this analogy, the shopping cart is like the materials being moved, the hill represents the cell membrane, and the energy you exert is similar to the energy cells use during active transport to move substances from a lower to a higher concentration.