Chapter 7, Problem 6MCQ

Summary Introduction

Introduction:

The plasma membranes are selectively permeable as the proteins mosaic lets only some selected molecules to pass through it. The transport of these selected molecules occurs in two ways: Passive transport, in which the movement of molecules across the membranes occurs by diffusion along the concentration gradient. It includes osmosis, facilitated diffusion, and simple diffusion. In energy-requiring transport, the movement of molecules across the cell membranes, against the concentration gradient, is facilitated by the expense of energy by the cell. It includes exocytosis, endocytosis, and active transport.