A Major Group of G Protein-Coupled Receptors Contains Seven Transmembrane

Multiple Choice

A major group of G protein-coupled receptors contains seven transmembrane α helices. The amino end of the protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on the cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others.
The coupled G protein most likely interacts with this receptor

A) at the NH3 end.
B) at the COO- end.
C) along the exterior face of the membrane.
D) at the loop between helices 5 and 6.