---
title: "Electrochemical Gradient — AP Bio Definition & Exam Guide"
description: "An electrochemical gradient combines concentration and charge differences across a membrane to drive ion movement, the force behind facilitated diffusion and action potentials in AP Bio Unit 2."
canonical: "https://fiveable.me/ap-bio/key-terms/electrochemical-gradient"
type: "key-term"
subject: "AP Biology"
---

# Electrochemical Gradient — AP Bio Definition & Exam Guide

## Definition

An electrochemical gradient refers to the combined concentration and electrical gradient across a cell membrane, which determines the direction in which ions move.

## Review

### Related Terms

- [Active Transport](/ap-bio/key-terms/active-transport): Active transport is a type of membrane transport that requires energy expenditure by the cell to move substances against their electrochemical gradients.
- [Diffusion](/ap-bio/key-terms/diffusion): Diffusion is a passive process where particles move from an area of higher concentration to an area of lower concentration, down their electrochemical gradient.
- [Facilitated Diffusion](/ap-bio/key-terms/facilitated-diffusion): Facilitated diffusion is a type of passive transport that uses specific carrier proteins or channel proteins to allow substances to move down their electrochemical gradients.