What is a direct consequence of the activation of transducin during phototransduction?

The activation of transducin during phototransduction has a direct consequence of hydrolysis of cyclic GMP. When photons hit photoreceptor cells in the retina, they cause a change in the conformation of rhodopsin, activating it. The activated rhodopsin then activates transducin, a G-protein.

Once transducin is activated, it binds to and activates phosphodiesterase (PDE6). This enzyme works to hydrolyze cyclic GMP (cGMP) to GMP. In normal dark conditions, cGMP levels are higher, helping to keep sodium channels in the photoreceptor cell membrane open, which allows sodium ions to enter the cell. However, when cGMP levels decrease due to the action of PDE6, these channels close, leading to hyperpolarization of the photoreceptor cell and a decrease in neurotransmitter release.

Thus, the hydrolysis of cyclic GMP is a crucial step in the cascade of events that leads to the phototransduction process, ultimately converting the light signal into a neural signal that can be processed by the brain. This is why the choice indicating hydrolysis of cyclic GMP is recognized as a direct consequence of transducin activation.