Writing Exercise
2/2/11
...insert obligatory "my English prof is making me do this paraphrase assignment" here...
Anyone that knows me could tell you that I have a great interest in food crop production. I have worked doing research on fruit crops in the Okanagan Valley for Agriculture and Agri-Food Canada and am planning on going back to do more research this summer, and I love the books of Michael Pollan, Jared Diamond, and Wendell Barry. Of particular interest to me is how we are going to deal with the ever-rising world population. The obvious answer is "just move the food around....we are already making enough!" But we couldn't possibly do that could we? So instead, science and brilliant scientists are attempting to answer the foreboding Malthusian wave. I have written papers for classes before on GM crops looking at their benefits and disadvantages, but I decided for this class paper to look at the development of transgenic C4 rice. While the advancements that were so promising early on seemed to have cooled off, a recent influx of papers synthesizing a lot of the information that we had with some of the new molecular and genetic research over the past few years seems to be occurring. The paragraph I am attempting comes from a review paper published in Plant Physiology online in October 2010 and in print in January 2011. Here is a link to the paper (as it is open access!)
The ultimate goal of photosynthesis is the fixation of carbon dioxide through the utilization of the enzyme RuBisCO (Ribulose-1,5-bisphosphate carboxylase oxygenase). However, RuBisCO is extremely inefficient in carrying out this process under normal atmospheric conditions. Under optimal conditions, RuBisCO catalyzes the carboxylation reaction of one molecule of ribulose-1,5-bisphosphate (RuBP) into two molecules of 3-phosphoglycerate; however, as the Earth's atmosphere has an approximate O2:CO2 ratio of 20:1, the oxygenation reaction in which one molecule of RuBP is converted into one molecule of 3-phosphoglycerate and one molecule of 2-phosphoglycolate is predominant. In order to recover the carbon atoms tied up in the 2-phosphoglycolate molecule, a relatively useless and somewhat toxic (in high enough concentrations) compound, a salvage pathway called photorespiration needs to be employed which consequently wastes valuable ATP (Anderson, 1971). The ultimate result of this process when coupled with other environmental factors like drought and raised temperatures is a decreased photosynthetic efficiency (Ehleringer et al., 1991). In looking at the specific evolutionary history of RuBisCO, it is easy to see how this situation may have evolved as three billion years ago, when this enzyme was first thought to have evolved, the atmospheric concentration of CO2 was high and O2 was low. Over time, it seems as though this original arrangement was unable to be changed nor was another carboxylase able to be substituted. Despite this, some plants have evolved various coping mechanisms including the C4 and CAM photosynthetic pathways.
More on this topic to come as I write my paper...
Anyone that knows me could tell you that I have a great interest in food crop production. I have worked doing research on fruit crops in the Okanagan Valley for Agriculture and Agri-Food Canada and am planning on going back to do more research this summer, and I love the books of Michael Pollan, Jared Diamond, and Wendell Barry. Of particular interest to me is how we are going to deal with the ever-rising world population. The obvious answer is "just move the food around....we are already making enough!" But we couldn't possibly do that could we? So instead, science and brilliant scientists are attempting to answer the foreboding Malthusian wave. I have written papers for classes before on GM crops looking at their benefits and disadvantages, but I decided for this class paper to look at the development of transgenic C4 rice. While the advancements that were so promising early on seemed to have cooled off, a recent influx of papers synthesizing a lot of the information that we had with some of the new molecular and genetic research over the past few years seems to be occurring. The paragraph I am attempting comes from a review paper published in Plant Physiology online in October 2010 and in print in January 2011. Here is a link to the paper (as it is open access!)
The ultimate goal of photosynthesis is the fixation of carbon dioxide through the utilization of the enzyme RuBisCO (Ribulose-1,5-bisphosphate carboxylase oxygenase). However, RuBisCO is extremely inefficient in carrying out this process under normal atmospheric conditions. Under optimal conditions, RuBisCO catalyzes the carboxylation reaction of one molecule of ribulose-1,5-bisphosphate (RuBP) into two molecules of 3-phosphoglycerate; however, as the Earth's atmosphere has an approximate O2:CO2 ratio of 20:1, the oxygenation reaction in which one molecule of RuBP is converted into one molecule of 3-phosphoglycerate and one molecule of 2-phosphoglycolate is predominant. In order to recover the carbon atoms tied up in the 2-phosphoglycolate molecule, a relatively useless and somewhat toxic (in high enough concentrations) compound, a salvage pathway called photorespiration needs to be employed which consequently wastes valuable ATP (Anderson, 1971). The ultimate result of this process when coupled with other environmental factors like drought and raised temperatures is a decreased photosynthetic efficiency (Ehleringer et al., 1991). In looking at the specific evolutionary history of RuBisCO, it is easy to see how this situation may have evolved as three billion years ago, when this enzyme was first thought to have evolved, the atmospheric concentration of CO2 was high and O2 was low. Over time, it seems as though this original arrangement was unable to be changed nor was another carboxylase able to be substituted. Despite this, some plants have evolved various coping mechanisms including the C4 and CAM photosynthetic pathways.
More on this topic to come as I write my paper...
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