BIOL 102 Lecture Notes - Lecture 29: Dna Replication, B Vitamins, Melatonin
Document Summary
Light can damage biological molecules but all organisms have developed mechanisms to help prevent or repair light induced damage. A good example of light damage on a biological process is found within photosynthesis. The photosynthetic apparatus is composed of many photosystem and each photosystem takes in about 10 000 photons every second. This high energy within the core can result in damage to the protein components. The damage is unavoidable but the rapid repair of photosystems developed early during the evolution of life so that the rate of photosynthesis can be maintained even under high light conditions. Plants also have carotenoids that take in the excess light and safely dispose it as heat. Even though carotenoids are not present in great quantities like chlorophyll, plants need to synthesize them and if the plants can"t they will turn white since the chlorophyll becomes oxidized and it loses its light harvesting capabilities.
