With active transport, ATP is involved. Generally, active transport can move particles UP their concentration gradient (aid in unfavorable processes). An example of primary transport is primary active transport, in which ions are moved across the membrane, a process that creates a difference in the charge across the membrane. Another type of ATP is secondary active transport, or co-transport, which does not directly require ATP but piggybacks off of ATP-involved processes. After primary active transport occurs, for example, and pushes material out of the cell against its concentration, there is a movement of material back into the cell (the drive of the concentration gradient is so large). This net movement of solute into the cell opens doors for other large molecules, such as sucrose, to enter the cell as well.
Specific carrier proteins or pumps help active transport occur: there are uniporters (carries one specific ion or molecule, both in same direction), symporters (carries two different ions or molecules, both in same direction), and antiporters (carries two different ions or molecules, in different directions). All of these transporters can carry small, uncharged organic molecules like glucose, and they can be involved in facilitated diffusion (passive) if no ATP is involved
