Coursework.Info - Inspiration in an Instant

On the left is an image preview of every page of this document, and below are the first 150 words with formatting removed:

Louise Weston Nitrogen Metabolism Describe how and why bacteria regulate their nitrogen metabolism. Nitrogen is essential for all living organisms being a constituent of nucleic acids and amino acids. 79% of the air is N2 however, most organisms can not use nitrogen in this form and must secure it in a fixed form such as NH3. Nitrogen fixing bacteria are known as diazotrophs. Relatively few bacteria fix nitrogen. Of those that do, most are free-living species, some however engage in symbiotic associations with plants where the bacteria provide the pant with fixed nitrogen and the plant provides fixed carbon to the bacteria. In marine environments the bulk of nitrogen fixation is carried out by cyanbacteria. Fixation is energetically costly and so if a fixed source of nitrogen is available it will be used primarily. The levels of such metabolites are sensed through the ntr system described below. In virtually all cells glutamate and glutamine serve as...

To see the full version of this document, and 145,345 others