Transmembrane proteins
(I)are predominantly constructed of a single hydrophobic α-helix.
(II)are often constructed from bundles of hydrophobic $\alpha$-helices.
(III)are sometimes constructed from β-barrels with hydrophobic interiors and exteriors.
(IV)may have transmembrane helices identified by the free energy of transfer to water.
A)I,III,IV
B)II,III
C)II,III,IV
D)I,IV
E)II,IV

Question

Quizplus · Accepted Answer

Transmembrane proteins can be constructed from bundles of hydrophobic α-helices (II) or from β-barrels with hydrophobic interiors and exteriors (III). They can also have transmembrane helices identified by the free energy of transfer to water (IV), but they are not predominantly constructed of a single hydrophobic α-helix (I). Therefore, the best choice is C.

Transmembrane Proteins (I)are Predominantly Constructed of a Single Hydrophobic α-Helix α\alphaα

Transmembrane Proteins
(I)are Predominantly Constructed of a Single Hydrophobic α-Helix $\alpha$