AP BIOLOGY

Detailed explanation-1: -Proteins embedded within the phospholipid bilayer carry out the specific functions of the plasma membrane, including selective transport of molecules and cell-cell recognition.

Detailed explanation-2: -Channels. Channel proteins span the membrane and make hydrophilic tunnels across it, allowing their target molecules to pass through by diffusion.

Detailed explanation-3: -Embedded in the phospholipid bilayer are proteins that also aid in diffusion and in cell recognition. Large molecules like carbohydrates use transport proteins to help move across cell membranes. Transport proteins go all the way through the bilayer and so are called integral proteins.

Detailed explanation-4: -Integral proteins are nestled into the phospholipid bilayer and stick out on either end. Integral proteins are helpful for transporting larger molecules, like glucose, across the cell membrane.

Detailed explanation-5: -Cells use exocytosis to secrete molecules too large to pass through the cell membrane by any other mechanism.