Lipid-soluble signalling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells because
A) only target cells retain the appropriate DNA segments.
B) intracellular receptors are present only in target cells.
C) only target cells have enzymes that break down aldosterone.
D) only in target cells is aldosterone able to initiate the phosphorylation cascade that turns genes on.

Question

Quizplus · Accepted Answer

Lipid-soluble signalling molecules, such as aldosterone, can diffuse across the membranes of all cells. However, they can only affect target cells because only target cells have intracellular receptors that bind to the signalling molecule, triggering a response within the cell. Other choices (A, C, and D) do not accurately describe the mechanism of lipid-soluble signalling.

Lipid-Soluble Signalling Molecules, Such as Aldosterone, Cross the Membranes of All