Chapter 5, Problem 12SQ

Summary Introduction

Introduction: Metabolic pathways require the participation of molecules that must move across membranes and through cells. The plasma membrane is composed of the lipid bilayer. It is nonpolar in nature. Large polar molecules and ions cannot move through the lipid bilayer, but nonpolar molecules and can small polar molecules can move through it by diffusion. For large polar molecules and ions, there is a special protein called transport protein through they cross the lipid bilayer.