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The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation ...
Nitrogen-15 is frequently used in NMR (Nitrogen-15 NMR spectroscopy). Unlike the more abundant nitrogen-14, which has an integer nuclear spin and thus a quadrupole moment, 15 N has a fractional nuclear spin of one-half, which offers advantages for NMR such as narrower line width. Nitrogen-15 tracing is a technique used to study the nitrogen cycle.
Nitrogen is a vital macronutrient for plants, necessary for the biosynthesis of many basic cellular components, such as DNA, RNA and proteins. Nitrogen is obtained by plants through roots from inorganic or organic sources, such as amino acids. [1] In agricultural settings, nitrogen may be a limiting factor for plant growth and yield, and in ...
Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N 2, a colorless and odorless diatomic gas.
Approximately 78% of Earth's atmosphere is N gas (N 2), which is an inert compound and biologically unavailable to most organisms.In order to be utilized in most biological processes, N 2 must be converted to reactive nitrogen (Nr), which includes inorganic reduced forms (NH 3 and NH 4 +), inorganic oxidized forms (NO, NO 2, HNO 3, N 2 O, and NO 3 −), and organic compounds (urea, amines, and ...
The standard free-energy scale is measured in electron-volts, [1] and the nE° = 0 value is usually the neutral species of the pure element. The Frost diagram normally shows free-energy values above and below nE° = 0 and is scaled in integers. The y axis of the graph displays the free energy. Increasing stability (lower free energy) is lower ...
The nitrogen cycle is one of the Earth's biogeochemical cycles. It involves the conversion of nitrogen into different chemical forms. The main processes of the nitrogen cycle are the fixation, ammonification, nitrification, and denitrification. As one of the macronutrients, nitrogen plays an important role in plant growth.
Morphology and characteristics. Nitrobacter are gram-negative bacteria and are either rod-shaped, pear-shaped or pleomorphic. [1][2] They are typically 0.5–0.9 μm in width and 1.0–2.0 μm in length and have an intra-cytomembrane polar cap. [5][2] Due to the presence of cytochromes c, they are often yellow in cell suspensions. [5]