Earth's atmosphere is nearly 80% nitrogen (N) but then the element is not sufficiently available to the organisms. It is known that some of the organisms have the capacity to assimilate molecular nitrogen and convert it into assumable form (Fig. 11-1). In general, four main types of organisms are recognized which can assimilate molecular nitrogen. These are symbiotic microorganisms inhabiting [...]
The below mentioned article provides a short note on reductase synthesis. Ammonia produced after nitrogen fixation is either immediately converted to organic nitrogen or to nitrate by nitrifying bacteria like Nitrosomonas in soil. The nitrates are then taken up by the plants and reduced to ammonia by a series of enzymes involving eight electrons transfer per molecule of NH3 formed. [...]
The minimum number of molecules of pigment and other associated compounds which are capable of converting a quantum is known as photosynthetic unit. When the electron microscopy revealed quantasomes on the lamellae of the chloroplast, most of the scientists believed that they had discovered a photosynthetic unit. However, Anderson and Boardman (1966) first of all raised the question whether the [...]