---
title: "Channel Protein — AP Bio Definition & Exam Guide"
description: "A channel protein is a membrane protein that forms a pore letting ions and polar molecules cross the hydrophobic interior, the basis of selective permeability in AP Bio Unit 2."
canonical: "https://fiveable.me/ap-bio/key-terms/channel-protein"
type: "key-term"
subject: "AP Biology"
---

# Channel Protein — AP Bio Definition & Exam Guide

## Definition

Channel proteins are integral membrane proteins that form channels or pores in the plasma membrane. They allow specific ions or molecules to pass through them, facilitating transport across the membrane.

## Review

### Related Terms

- Carrier Protein: Another type of integral membrane protein involved in facilitated diffusion or active transport across membranes.
- Ion Channel: A type of channel protein specifically dedicated to transporting ions across cell membranes.
- Aquaporin: A specialized channel protein that allows water molecules to rapidly cross cell membranes.