What describes integral proteins in cell membranes?

Integral proteins, also known as intrinsic proteins, are indeed bonded to the entire membrane. They are embedded within the lipid bilayer and extend across the membrane, often spanning it completely. This unique trait allows integral proteins to play key roles in a variety of cellular functions, including serving as channels for ion and molecule transport, acting as receptors for signaling molecules, and contributing to the structural integrity of the membrane.

The bonding with the membrane is significant because it supports their function in maintaining the structure of the cell and facilitating communication and transport across the cell membrane. Removing integral proteins generally requires disruption of the lipid bilayer, unlike peripheral proteins, which can be more easily detached.

In contrast to the description of integral proteins, the other options do not accurately reflect their characteristics. While they can have enzymatic functions, they do not solely serve as enzymes, making the fourth option misleading. Integral proteins are also not exclusively located on the outer layer of the membrane; they span across both sides of the lipid bilayer. The assertion that they can be easily removed is also incorrect, as their association with the membrane's hydrophobic core means they are more firmly attached compared to peripheral proteins.