Q1. The most important group of G protein-linked receptors contain seven transmembrane alpha 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 generally substantially longer than the others.

The coupled G protein most likely interacts with this receptor.

Q2. Identify species. Does this definition be relevant to ALL life? Provide an instance where this definition does not apply and in brief explain why this example does not apply to the species concept.