Complex sentence: A transmembrane protein (TP) is a type membrane protein--specifically, an integral membrane protein--that spans from one side of a cell membrane through to the other side of the membrane.
Split into simpler sentences: A transmembrane protein (TP) is a type membrane protein--specifically, an integral membrane protein--that spans the entirety of a biological membrane. That is, transmembrane proteins span from one side of a membrane through to the other side of the membrane.