[Campbell Biology P.178] Based on Figure 7.6 and the accompanying text, which statement corr... | Practice Question

Based on Figure 7.6 and the accompanying text, which statement correctly describes the structure and orientation of the transmembrane protein bacteriorhodopsin?

  • A: Its N-terminus is located on the cytoplasmic side, and its C-terminus is on the extracellular side.
  • B: It consists of seven nonhelical hydrophilic segments that span the membrane.
  • C: Its hydrophobic regions, primarily composed of alpha helices, are embedded within the lipid bilayer's interior.
  • D: It allows passage of only hydrophobic substances through its hydrophilic channels.

Explanation

Figure 7.6 and its caption specify that bacteriorhodopsin's hydrophobic parts, including seven transmembrane alpha helices, lie mostly within the hydrophobic interior of the membrane. The N-terminus is extracellular, and the C-terminus is cytoplasmic.