Ammonium generated in nitrogen fixation can be incorporated into glutamate to form what molecule?
A Threonine
B Tyrosine
C Alpha-ketoglutarate
D Glutamine
E Alanine
The correct answer and explanation is:
The correct answer is D Glutamine.
In nitrogen fixation, ammonium (NH₄⁺) is generated as a byproduct and can be incorporated into organic molecules through a process known as nitrogen assimilation. One of the key steps in nitrogen assimilation involves the conversion of ammonium into glutamine.
The process begins with the enzyme glutamine synthetase catalyzing the incorporation of ammonium into glutamate, a key amino acid involved in nitrogen metabolism. Glutamate is then converted into glutamine through the action of glutamine synthetase. This conversion involves the addition of ammonium to glutamate, producing glutamine (Gln). This reaction is important because it helps to store and transport nitrogen within cells in a non-toxic form.
Glutamine is a crucial amino acid that serves as a nitrogen donor in many biosynthetic pathways. It is involved in the synthesis of nucleotides, amino acids, and other biomolecules. It also plays a key role in maintaining nitrogen balance in plants, bacteria, and animals by providing a reservoir of nitrogen that can be used when needed for growth and metabolism.
In plants, glutamine can also be involved in the regulation of nitrogen metabolism. It is often transferred to other tissues and organs where it can be converted back into glutamate or used for the synthesis of other amino acids. Similarly, in animals, glutamine is involved in maintaining the nitrogen balance, especially during periods of high metabolic demand, such as during growth or in response to stress.
In summary, ammonium produced during nitrogen fixation is incorporated into glutamate and converted into glutamine, which plays a vital role in nitrogen metabolism and the biosynthesis of other important biomolecules.