Emergency Medical Technician (EMT) Intermediate Practice Exam 2026 – 400 Free Practice Questions to Pass the Exam

Facilitated transport, also known as facilitated diffusion, occurs when substances move across a cell membrane via protein channels or carriers without the need for energy expenditure. This process is driven by the concentration gradient, meaning substances naturally flow from an area of higher concentration to one of lower concentration until equilibrium is reached. This method is essential for the transport of polar molecules and ions that cannot directly pass through the lipid bilayer of the cell membrane.

In contrast, active transport requires energy, usually in the form of ATP, to move substances against their concentration gradient. Bulk transport, including processes like endocytosis and exocytosis, involves the movement of large quantities of materials into or out of the cell, which also requires energy. Therefore, facilitated transport is the only option that allows for the passive movement of molecules, highlighting its significance in cellular processes.