Sandbox reserved 457: Difference between revisions
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== Mechanism == | == Mechanism == | ||
Nitrogen fixation by bacteroids provides ammonia, which is integrated by the plant into biomolecules, such as proteins, nucleic acids and alkaloids. The plant then supplies the bacteroids with sugars. The process takes place at the root nodules, which are tumor-like structures formed as a result of the infection of roots by the bacteria. The heme group is synthesized by the bacteroids and the globin is synthesized by the ribosomes of the infected cells. Once this synthesis is complete, the heme and globin are joined in the cytoplasm of the plant cell. | Nitrogen fixation by bacteroids provides ammonia, which is integrated by the plant into biomolecules, such as proteins, nucleic acids and alkaloids. The plant then supplies the bacteroids with sugars. The process takes place at the root nodules, which are tumor-like structures formed as a result of the infection of roots by the bacteria. The heme group is synthesized by the bacteroids and the globin is synthesized by the ribosomes of the infected cells. Once this synthesis is complete, the heme and globin are joined in the cytoplasm of the plant cell. | ||
In root nodules the O2 level is regulated by a special hemoglobin - leghemoglobin. The globin protein is encoded by plant genes but the heme cofactor is made by the symbiotic bacteria. This is produced only when the plant is infected with Rhizobium. The plant root cells convert sugar to organic acids which they supply to the bacteroids. In exchange, the plant receives amino-acids (rather than free ammonia).<ref></ref> | In root nodules the O2 level is regulated by a special hemoglobin - leghemoglobin. The globin protein is encoded by plant genes but the heme cofactor is made by the symbiotic bacteria. This is produced only when the plant is infected with Rhizobium. The plant root cells convert sugar to organic acids which they supply to the bacteroids. In exchange, the plant receives amino-acids (rather than free ammonia).<ref>a-s.clayton.edu/science/Biocomputing/Projects/.../Leghemoglobin.ppt</ref> | ||
== Function == | == Function == | ||