Lipid-soluble signal molecules, such as testosterone, cross the membranes of all cells but affect only target cells because:

(A) only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor.

(B) only target cells retain the appropriate DNA segments.

(C) intracellular receptors are present only in target cells.

(D) most cells lack the Y chromosome required.

(E)only target cells possess the cytosolic enzymes that transduce the testosterone.

Which of the following is a correct association?

(A) adenylyl cyclase activity and the conversion of cAMP to AMP

(B) kinase activity and the addition of a tyrosine

(C) phosphorylase activity and the catabolism of glucose

(D) GTPase activity and hydrolysis of GTP to GDP

(E) phosphodiesterase activity and the removal of phosphate groups

Which is NOT a basic method of cell-to-cell communication?

(A) mechanical signals

(B) diffused chemical signals

(C) nerve and blood-transported signals

(D) cytoplasmic transfer of signals

(E) contact-dependent signals