文档介绍：M1. Nitrogen Fixation and Assimilation
M2. Amino acid metabolism
M3. The urea cycle
M4. Hemes and chlorophylls
Section M Nitrogen Metabolism
1. The nitrogen cycle
2. Nitrogen fixation
3. Nitrogen assimilation 同化作用
Nitrogen fixation and assimilation
The nitrogen cycle
The nitrogen cycle is the movement of nitrogen through the food chain from simple pounds , mainly ammonia, pounds .
脱氨作用
分解代谢
Nitrogen fixation
Nitrogen fixation is the conversion of N2 gas into ammonia, a process carried out by some soil bacteria, cyanobacteria蓝细菌, and the symbiotic 共生的 bacteria Rhizobium 根瘤菌that invade the root nodules of leguminous豆类 plants.
Nitrogen fixation
This process is carried out by the plex, which consists of a reductase and an iron-molybdenum 钼-containing nitrogenase. At least 16ATP molecules are hydrolyzed to form two molecules of ammonia. Leghemoglobin 豆血红蛋白is used to protect the nitrogenase in the Rhizobium from inactivation by O2 .
nitrogenase
铁氧还蛋白
Nitrogen assimilation
Ammonia is assimilated by anisms anic nitrogen-pounds(amino acids,nucleotides,etc.) by the action of glutamate dehydrogenase (to form glutamate) and glutamine synthetase (to form glutamine).
Amino acid family
Amino acid degradation
Amino acids are degraded by the removal of the α-amino group and the conversion of the resulting carbon skeleton into one or more metabolic intermediates.