Some chemical signal molecules are excluded from entering the cell whereas others are able to enter. Based on your knowledge of the structure of cell membranes, which of the following signal molecules would be able to pass through the cell membrane?
A) Water-soluble chemical signals
B) Esterified chemical signals
C) Phenolic-based chemical signals
D) Carbonylic chemical signals
E) Lipid-soluble chemical signals

Question

Quizplus · Accepted Answer

Lipid-soluble signal molecules can easily pass through the lipid bilayer of cell membranes because they are hydrophobic, similar to the interior of the membrane. Water-soluble signals, on the other hand, cannot easily cross the hydrophobic core of the membrane and typically require membrane-bound receptors to facilitate their effect inside the cell.

Some Chemical Signal Molecules Are Excluded from Entering the Cell