Proteins that are embedded within, and extend across, the phospholipid bilayer are called proteins. integral cytoskeleton catalytic peripheral

Proteins that are embedded within, and extend across, the phospholipid bilayer are called integral proteins.  Integral proteins (intrinsic membrane proteins) are any membrane-bound proteins which interact with the hydrophobic part of the phospholipid bilayer. Those proteins are permanently attached to the biological membrane and can be removed from it only by extraction with detergent.

Aneutral atom must have the same number of neutrons and protons? no, they must have the same number of protons and electrons