29. Explain the process of phototransduction.
light → opsin → metarhodopsin → G-Protein transducin → photodiesterase → cGMP → kations (calcium and sodium) entering the photoreceptor cells (back to GMP) → opening CNG channels (in the dark cGMP leaves them open for longer) → depolarization of photoreceptor cell
→ glutamate → depol. on-bipolar, hyperpol. off-bipolar
light → 11-cis → trans-retinal (starting process)