BI108 Chapter 6 Outline: Cell Membranes
6.1—What Is the Structure of a Biological Membrane?
• Lipids form the hydrophobic core of this membrane
• Membrane proteins are asymmetrically distributed
• Membranes are constantly changing
• Plasma membrane carbohydrates are recognition sites
The fluid mosaic model applies to the plasma membrane and the membranes or
organelles. An integral membrane protein has both hydrophilic and hydrophobic
domains, which affect its position and function in the membrane. Carbohydrates that
attach to lipids and proteins on the outside of the membrane serve as recognition sites
6.2—How Is the Plasma Membrane Involved in CellAdhesion and Recognition?
• Cell recognition and adhesion involve proteins and carbohydrates at the cell surface
• Three types of cell junctions connect adjacent cells
• Cell membranes adhere to the extracellular matrix
In multicellular organisms, cells arrange themselves into tissues via the processes of cell
recognition and cell adhesion. These processes are mediated by membrane-associated
proteins and carbohydrates. Cell membrane proteins also interact with the extracellular
matrix. Cell junctions assist in strengthening tissues and allow cells to communicate with
6.3—WhatAre the Passive Processes of Membrane Transport?
• Diffusion is the process of random movement toward a state of equilibrium