Transport of Glucose Through the Cell Membrane Before glucose can be used by the body‘s tissue cells, it must be transported through the tissue cell
membrane into the cellularcytoplasm. However, glucose cannot easily diffuse through the pores of the
cell membrane because themaximummolecular weight of particles that can diffuse readily is about
100, and glucose has a molecular weight of 180. Yet glucose does passto the interior of the cells with a
reasonable degree of freedom by the mechanism of facilitated diffusion. The principles of this type of
transport are discussed in Chapter 4. Basically, they are the following. Penetrating through the lipid
matrixof the cell membrane are large numbers of protein carrier molecules that can bind with glucose.
In this bound form, theglucose can be transported by the carrier from one side of the membrane to the
other side and then released.
