BIOL 1010 Lecture Notes - Atp Synthase, Stoma, Carboxylation
Document Summary
Chlorophyll a, the pigment that participates directly in the light reactions of photosynthesis, has a head called a porphyrin ring, with a magnesium atom at its center. Attached to the porphyrin is a hydrocarbon tail which interacts with hydrophobic regions of proteins in the thylakoid membrane. Chlorophyll b differs from chlorophyll a only in one of the functional groups bonded to the porphyrin. A) absorption of a photon causes a transition of the chlorophyll molecule from its ground state to its excited state: the photon boosts an electron to an orbital where it has more potential energy. If isolated chlorophyll is illuminated, its excited electron immediately drops back down to the ground-state orbital, giving off its excess energy as heat and fluorescence (light) B) a chlorophyll solution excited with ultraviolet light with fluoresces, giving off a red-orange glow. Chlorophyll a, chlorophyll b and the carotenoids are assembled into photosystems located within the thylakoid membrane.
