What term describes proteins that span the membrane of a cell?

The term that describes proteins that span the membrane of a cell is integral proteins. These proteins are embedded within the lipid bilayer of the cell membrane and can extend across the entire membrane, playing a crucial role in various cellular functions such as transport, signaling, and structural support.

Integral proteins are often involved in the formation of channels or pores that allow specific molecules to pass through the membrane, which is essential for maintaining cellular homeostasis. Since they are integral to the membrane structure, they cannot easily be removed without disrupting the membrane itself.

While transmembrane proteins specifically refer to a subtype of integral proteins that extend across the membrane, the broader term "integral proteins" encompasses all proteins that are permanently attached to the membrane. This is why integral proteins are the correct term when discussing proteins that span the entire membrane of a cell.