BIOA02H3 Chapter 8: chapter 8

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BIOA02H3 Full Course Notes
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Life depends on absorption of light energy from sun not very efficient ~ 4% of light actually used. Pigments absorb light in visible spectrum (400 700nm: most common pigment in all photoautotrophs is chlorophyll plants, some algae an cyanobacteria havechlorophyll a. Absorbtion in blue (400-450 nm) and red (650-700 nm) Chlorophyll appears green because it reflects green wavelengths (500 to 600 nm) Accessory pigments include carotene, phycocyanin, phycoerythrin, xanthophylls have characteristic absorption spectra that reveals their biological effectiveness at different wavelengths of light. Chlorophyll molecule reaction center a special pigment molecule where energy from photons of light is concentrated act as antennae to maximize light absorption electrons pass down energy gradient from higher energy (shorter l energy (longer l. Electrons pass from one to another pigment molecule within photsystem. Light dependent reactions process responsible for aerobic oxygenic atmosphere occurs in photoautotrophic organisms.