Passive transport

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Passive transport" – news · newspapers · books · scholar · JSTOR (November 2022) (Learn how and when to remove this message)

Passive transport is a type of membrane transport that does not require energy to move substances across cell membranes.^[1][2] Instead of using cellular energy, like active transport,^[3] passive transport relies on the second law of thermodynamics to drive the movement of substances across cell membranes.^[1][2][4] Fundamentally, substances follow Fick's first law, and move from an area of high concentration to an area of low concentration because this movement increases the entropy of the overall system.^[4][5] The rate of passive transport depends on the permeability of the cell membrane, which, in turn, depends on the organization and characteristics of the membrane lipids and proteins.^{[citation needed]} The four main kinds of passive transport are simple diffusion, facilitated diffusion, filtration, and/or osmosis.

Passive transport follows Fick's first law.