<prompt> Where is the location of heme in hemoglobin?Hydrophilic pocketsHydrophobic pocketsPyrrole ringsCationic ring  <response>: The amino acid sequences of the various globins are highly homologous to one another. Each has a highly helical secondary structure. Their globular teiary structures cause the exterior surfaces to be rich in polar hydrophilic amino acids that enhance solubility, and the interior to be lined with nonpolar groups, forming a hydrophobic pocket into which heme is inseed. Ref: Benz, E.J. 2012. Chapter 104. Disorders of Hemoglobin. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo Eds, Harrisons Principles of Internal Medicine, 18e. 