In an alpha-helical protein that spans a cell membrane, _____ would likely be in the center of the membrane while _____ would likely be associated with the polar head groups and _____ would likely be associated with the aqueous environment.
a. Tyr; Glu; Gly
b. Val; Ser; Thr
c. Ile; Arg; Gln
d. Trp; Asn; Ala
e. Leu; Gln; Asp