BIOL 1000 Study Guide - Midterm Guide: Photopsin, Photoreceptor Cell, Opsin
10 Oct 2016
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Light: portion of electromagnetic spectrum than humans can detect with their eyes. It"s a (cid:449)a(cid:448)e of dis(cid:272)rete parti(cid:272)les (cid:272)alled photo(cid:374)s. Electromagnetic radiation: radiation including visible light, radio waves, gamma rays, x-rays in which electric & magnetic fields vary simultaneously. Wavelength: different wavelengths have different energy of light. Photon: light composed of stream of energy particles called photons. Light has properties of both wave & stream of photons. Shorter wavelength, greater energy of photons; longer wavelength, lower energy. Pigment: molecules that absorb photons: chlorophyll a: involved in photos thesis, retinal: found in rhodopsin. Absorption of light causes change in shape of retinal, which changes shape of opsin. Change in shape of opsin triggers events like electric signals: pig(cid:373)e(cid:374)t (cid:373)ole(cid:272)ules ha(cid:448)e (cid:272)ar(cid:271)o(cid:374) ato(cid:373) regio(cid:374) that"s (cid:272)o(cid:448)ale(cid:374)tly (cid:271)o(cid:374)ded to ea(cid:272)h other (cid:449)/ alternating single & double bonds. None of these electrons are closely associated w/atom or involved in bonding making them able to interact w/photons: pigments absorb lights at different wavelengths.
