This set of Biochemistry Multiple Choice Questions & Answers (MCQs) focuses on “Overview of Nitrogen Metabolism”.
1. Uridylylation and deuridylylation of PII are brought about by a single enzyme
a) Uridylyltransferase
b) Adenylyltransferase
c) Glutamate synthase
d) Dinitrogenase
View Answer
Explanation: Uridylylation and deuridylylation of PII are brought about by a single enzyme, uridylyltransferase.
2. Dinitrogenase reductase is a
a) Monomer
b) Dimer
c) Trimer
d) Tetramer
View Answer
Explanation: Dinitrogenase reductase is a dimer of two identical subunits.
3. Dinitrogenase is a
a) Monomer
b) Dimer
c) Trimer
d) Tetramer
View Answer
Explanation: Dinitrogenase is a tetramer with two copies of two different subunits, containing both iron and molybdenum.
4. The reaction of glutamate and NH4+ to yield glutamine is catalyzed by
a) Uridylyltransferase
b) Adenylyltransferase
c) Glutamate synthase
d) Glutamine synthase
View Answer
Explanation: Glutamine synthase catalyzes the reaction of glutamate and NH4+ to yield glutamine.
5. An intermediate of the citric acid cycle that undergoes reductive amination with glutamine as nitrogen donor is
a) α-ketoglutarate
b) Glutamine
c) NADPH
d) H+
View Answer
Explanation: α-ketoglutarate is the intermediate of the citric acid cycle that undergoes reductive amination with glutamine as nitrogen donor.
6. Which of the following catalyzes reactions that incorporate nitrogen derived from glutamine?
a) Glutamine amidotransferase
b) Adenylyltransferase
c) Glutamate synthase
d) Glutamine synthase
View Answer
Explanation: Glutamine amidotransferase catalyzes reactions that incorporate nitrogen derived from glutamine.
7. Conversion of nitrogen to ammonia or nitrogenous compounds is termed as
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation
View Answer
Explanation: Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called as nitrogen assimilation.
Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called as nitrification.
Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called as denitrification.
8. Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called as
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation
View Answer
Explanation: Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called as nitrification.
Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called as denitrification.
Conversion of nitrogen to ammonia or nitrogenous compounds is termed as nitrogen fixation.
9. Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called as
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation
View Answer
Explanation: Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called as denitrification.
Conversion of nitrogen to ammonia or nitrogenous compounds is termed as nitrogen fixation.
Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called as nitrogen assimilation.
10. Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called as
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation
View Answer
Explanation: Conversion of nitrogen to ammonia or nitrogenous compounds is termed as nitrogen fixation.
Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called as nitrogen assimilation.
Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called as nitrification.
Sanfoundry Global Education & Learning Series – Biochemistry.
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