Which statement is true about active transport?

Active transport is a process that moves molecules across a cell membrane against their concentration gradient, meaning from an area of low concentration to an area of high concentration. This movement requires energy because it is essentially working against the natural tendency of molecules to diffuse from areas of higher concentration to areas of lower concentration, which is characteristic of passive transport.

The energy required for active transport typically comes from adenosine triphosphate (ATP), which provides the necessary power for transport proteins or pumps to function. This is in stark contrast to passive transport, where no energy is required, as it relies on the natural movement of molecules down their concentration gradients.

In addition, active transport is inherently associated with cell membranes since it involves the specific transport proteins that span these membranes. Therefore, any statement suggesting that active transport does not involve cell membranes would be inaccurate.

By understanding the nature of active transport and its energy requirements, one can appreciate its vital role in maintaining cellular homeostasis and nutrient uptake.