Final answer:
Integral proteins within the plasma membrane, such as channel proteins and carrier proteins, facilitate the transportation of materials like glucose across the membrane via facilitated diffusion.
Step-by-step explanation:
Transport Across the Plasma Membrane
The part of the plasma membrane that helps transport materials such as glucose across it is facilitated by specific integral proteins. These proteins are essential for facilitated diffusion, an efficient process that enables larger and polar molecules, which cannot freely pass through the lipid bilayer, to move across the plasma membrane down their concentration gradients without expending energy. There are two main types of proteins involved in this process: channel proteins and carrier proteins. Channel proteins form pores made of beta-pleated sheets that allow substances to pass through. On the other hand, carrier proteins undergo a subtle change in shape to transport specific substances across the membrane.