BIOL 2303 Lecture Notes - Lecture 8: Green Sulfur Bacteria, Purple Bacteria, Purple Sulfur Bacteria
13 Mar 2018
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Document Summary
Photosynthesis: conversion of light energy into chemical energy. Prokaryotes carry out both types of photosynthesis, 6 different types of photosynthesis have evolved within bacteria. Important for ocean productivity: 80% of marine photosynthesis, 35% of all photosynthesis on earth, purple bacteria. In oxygenic phototrophs chlorophyll is the primary light absorbing pigment. In anoxygenic phototrophs bacteriochlorophyll is the primary light absorbing pigment. Both are always embedded in a membrane. Pigments present in different types of structures that increase surface area. Purple bacteria: folds or stacks of the cytoplasmic membrane called chromatrophores or lamellae. Cyanobacteria: pigments arranged in thylakoids concentric circles at periphery of cytoplasm. Chlorosomes: found in green sulfur bacteria and green non-sulfur bacteria. Green bacteria can live under very low light conditions. Typically absorb in the blue region of the spectrum. Autotrophy: co2 is reduced and converted into cellular material. Amongst photoautotrophs: several pathways: calvin cycle, reverse citric acid cycle, hydroxyproprionate pathway.
