Indicate whether each of the following descriptions applies to visual signal transduction (V), olfactory signal transduction (O), or both (B). Your answer would be a four-letter string composed of letters V, O, and B only, e.g. VOVV.
( ) It involves cGMP as a second messenger .
( ) A rise in cyclic mononucleotide concentration follows the arrival of the signal.
( ) The signal is received by a G-protein-coupled receptor.
( ) An incoming signal leads to membrane hyperpolarization.

Question

Indicate whether each of the following descriptions applies to visual signal transduction (V), olfactory signal transduction (O), or both (B). Your answer would be a four-letter string composed of letters V, O, and B only, e.g. VOVV.
( )	It involves cGMP as a second messenger	.
( )	A rise in cyclic mononucleotide concentration follows the arrival of the signal.
( )	The signal is received by a G-protein-coupled receptor.
( )	An incoming signal leads to membrane hyperpolarization.

Quizplus · Accepted Answer

Both smell and vision depend on G-protein-coupled receptors (GPCR) that egulate ion channels. Stimulation of olfactory receptors results in the opening of cyclic-AMP-gated cation channels (through the activation of G?lf) and membrane depolarization in the neuron. In vertebrate photoreceptors, in contrast, GPCR activation hyperpolarizes the cell: it closes cyclic-GMP-sensitive cation channels through the activation cyclic GMP phosphodiesterase by Gt.

Indicate Whether Each of the Following Descriptions Applies to Visual