What type of transport requires energy to move materials across a cell membrane?

Active transport is the type of transport that requires energy to move materials across a cell membrane. This process is essential for maintaining cellular function, as it allows cells to move substances against their concentration gradient, from an area of lower concentration to an area of higher concentration. This is particularly important for the uptake of ions and nutrients that are less concentrated outside the cell, as well as for removing waste products that the cell does not want.

The energy required for active transport typically comes from the hydrolysis of ATP (adenosine triphosphate). This investment of energy enables the cell to control its internal environment more precisely, maintaining homeostasis by regulating ion concentrations and other crucial parameters.

In contrast, diffusion, facilitated diffusion, and osmosis are processes that do not require energy, as they rely on the natural movement of molecules from regions of higher concentration to regions of lower concentration. These passive transport mechanisms occur spontaneously due to the molecular motions of the substances involved, allowing them to utilize the established gradients without expending cellular energy.