Consider a transmembrane protein with the topology on the right that has an internal signal sequence (helix 1). If you fuse a canonical ER signal sequence at the N-terminus of this protein, how would you expect the topology to change

lipid

explanation:

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.