The LDL receptor is an integral protein that crosses the plasma membrane, with portions of the protein extending both outside and into the interior of the cell. The amino acid side chains (R groups) in the region of the protein that crosses the membrane are most likely

Question

Quizplus · Accepted Answer

The region of the LDL receptor that crosses the plasma membrane is a transmembrane domain composed of hydrophobic amino acid side chains. Water-soluble molecules, such as amino acids with charged or polar R groups, do not easily cross the hydrophobic region of the membrane. Therefore, the most likely amino acid side chains in this region are hydrophobic, allowing the protein to anchor in the membrane.

The LDL Receptor Is an Integral Protein That Crosses the Plasma