BIOL 1000 Chapter Notes - Chapter 1: Electromagnetic Spectrum, Phytochrome, Conjugated System
8 Dec 2011
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The visible region of the electromagnetic spectrum, the only part we can see (380- Is decribed according to wavelength, but behave as massless particles called photons (energy packet). Light interacts with matter by: reflection, transmission, or absorbtion (with respect to an object). Pigments are molecules which mediate the amount of light energy absorbed by an object (varies). > have a molecular structure that allows them to absorb light. > pigments are made up of a series of covalently bonded (single and double) carbon atoms (conjugated system). Photosynthesis: sun -> cellular respiration -> energy. Photoreceptor (light sensor): a light sensitive protein involved in sensing and responding to light (ex; rhodopsin, bacteria rhodopsin, phytochrome). > mediate light responses, and responses to light and dark. Retinals is a pigment molecule which change shape when exposed to light yeilding a reaction. Senses light, and moves to it to maximize e uptake. Phototaxis : the direction of movement toward or away from a light stimulus.
