Unlike passive transport mechanisms, active transport requires the input of cellular .

Unlike passive transport mechanisms, active transport requires the input of cellular energy. This is because active transport is the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration. This movement is against the concentration gradient, and thus requires energy. The energy is usually in the form of adenosine triphosphate (ATP).

Here are the steps:

1. The molecule to be transported binds to a specific site on the carrier protein on the outside of the cell membrane.

2. The binding of the molecule causes a change in the shape of the carrier protein.

3. This change in shape triggers the release of an ATP molecule. The energy released from the ATP molecule is used to change the shape of the carrier protein.

4. The change in shape of the carrier protein allows the molecule to be moved across the cell membrane to the inside of the cell.

5. Once the molecule is inside the cell, it is released from the carrier protein. The carrier protein then returns to its original shape, ready to transport another molecule.

6. The spent ATP molecule is then recycled back into the cell to be recharged and used again for more active transport.