What is passive transport characterized by?

Passive transport is characterized by the movement of molecules down their concentration gradient. This means that substances move from an area of higher concentration to an area of lower concentration without the input of energy. This process occurs naturally due to the kinetic energy of molecules and is driven by the principle of diffusion, which seeks to equalize concentrations across a space.

The correct understanding of passive transport is crucial because it plays a vital role in various biological processes, such as nutrient uptake and waste removal, allowing cells to maintain homeostasis without expending energy. Since it relies on the natural flow of molecules, it is essential to grasp that passive transport does not require cellular energy (ATP) to facilitate this movement, contrasting it with active transport, which does require energy to move substances against their concentration gradient.