Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells becausea. 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.

The molecules that convert extracellular signals into intracellular signals are:

a) Neurotransmitters.

b) Hormones.

c) Cell surface receptors.

d) Intracellular receptors.

Which type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane?

a) Receptor tyrosine kinase.

b) G protein-coupled receptor.

c) Ligand-gated ion channel.

d) Steroid receptor.

e) Intracellular receptor.