During phototransduction, rhodopsin activates which G protein?

During phototransduction, rhodopsin activates transducin, which is a specific G protein found in the photoreceptor cells of the retina. When photons of light hit rhodopsin, it undergoes a conformational change that activates transducin by facilitating the exchange of GDP for GTP on its alpha subunit. This activation of transducin is a crucial step in the phototransduction cascade.

Once activated, transducin's GTP-bound alpha subunit can then activate phosphodiesterase, leading to a decrease in the levels of cyclic GMP (cGMP) in the photoreceptor cell. The decrease in cGMP ultimately results in the closure of cGMP-gated ion channels, causing hyperpolarization of the photoreceptor cell and initiation of the signaling pathway that leads to visual perception.

The other options refer to different components. Rho is a name sometimes associated with rhodopsin but not a G protein involved in activation. Phosphodiesterase is an enzyme that is activated by transducin, not a G protein itself. G-alpha is a generic term referring to the alpha subunit of G proteins but is not specific to the type of G protein activated by rh