Final answer:
The typical width of the lipid bilayer of a cell membrane is around 5 to 10 nanometers, with more specific estimates often citing 6 to 8 nanometers, according to the fluid mosaic model.
Step-by-step explanation:
The typical width of the lipid bilayer that makes up cell membranes is approximately 5 to 10 nanometers (nm). Specifically, the width is often cited as being in the range of 6 to 8 nanometers. This is based on the fluid mosaic model, which describes the plasma membrane structure as a mosaic of components including phospholipids, cholesterol, proteins, and carbohydrates. For comparison, the diameter of human red blood cells, which can be seen with light microscopy, is about 8 micrometers (μm), making the red blood cells roughly 1,000 times wider than the thickness of a plasma membrane. Therefore, the correct answer to the question about the typical width of the lipid bilayer is likely closer to 5 nanometers (nm), which falls within the provided range.