Biochemistry Lecture 6: Nitrogen Fixation and Metabolization

These flashcards cover key vocabulary and concepts related to nitrogen fixation, metabolization of amino acids, and nucleotide synthesis as described in the biochemistry lecture.

Nitrogen fixation

The conversion of atmospheric N2 into biologically available forms of nitrogen, such as ammonium (NH4+), nitrite (NO2-), and nitrate (NO3-).

Ammonification

The process of production of ammonium ions (NH4+) from the breakdown of organic nitrogen compounds by decomposers such as bacteria and fungi.

Assimilation

The absorption of nitrate (NO3-) or ammonium (NH4+) from the soil by plants for use in biological processes.

Nitrification

The biological oxidation of ammonium (NH4+) to nitrite (NO2-) followed by the oxidation of nitrite to nitrate (NO3-).

Denitrification

The conversion of nitrate (NO3-) back into nitrogen gas (N2) by denitrifying bacteria, completing the nitrogen cycle.

Glutamate (Glu)

An amino acid that serves a key role in amino acid metabolism and biosynthesis, especially as a nitrogen donor.

Glutamine (Gln)

An amino acid derived from glutamate that acts as a non-toxic transporter of ammonia in the urea cycle.

Transamination

A reaction in which an amino group from an amino acid is transferred to a keto acid, making a new amino acid.

Pyridoxal phosphate (PLP)

A coenzyme derived from vitamin B6 that is essential for the function of aminotransferases in transamination reactions.

Urea cycle

A series of biochemical reactions that convert ammonia to urea for excretion, involving intermediates that connect to the citric acid cycle.

Essential amino acids

Amino acids that cannot be synthesized by the human body and must be obtained from dietary sources, including Histidine, Leucine, and Methionine.

Purine synthesis

The biochemical pathway that synthesizes purine nucleotides, including AMP and GMP, from simpler molecules.

Pyrimidine synthesis

The biochemical pathway that constructs pyrimidine bases, attaching them to ribose-5-phosphate to form nucleotides.

Transaminases

Enzymes that catalyze transamination reactions, allowing for the transfer of amino groups between amino acids and alpha-keto acids.

Nucleotide biosynthesis

The process of synthesizing nucleotides from smaller molecules, involving pathways for both purines and pyrimidines.