Biology 1002B Lecture Notes - Lecture 5: Chlorophyll, Chloroplast Membrane, Channelrhodopsin
11 Apr 2017
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Document Summary
Chlamydmondas eyespot: structure and mechanism of function of the chlamydmonas eyespot. Light coming from rear is blocked from reaching the channelrhodopsin (molecule that leads to phototaxis: allows it to sense the direction the light originates from, phototransduction of the eyespot signal. Eye spot is not near the flagella (distance) Light perceived by eyespot cause changes in flagella movement: structure of channelrhodopsin. Light hits photon of light opens channel positively charged ions flow in (ca+, protons) depolarization: causes action potential runs along plasma membrane to flagella. The pigment must be associated with a protein: relationship between photon energy & electron excited states to explain pigment color & absorption spectrum. Polarized more negative ions inside than outside. Light absorption of chlorophyll: one photon excites one election. Red photon (low energy) excites to lower energy state. Lower excited state drives photosynthesis: electron in this state is easier to oxidize (further away from nucleus) Blue photon (high energy) excited to higher energy state.
