Biochemistry Questions and Answers – Overview of Nitrogen Metabolism

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

Answer: a
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

Answer: b
Explanation: Dinitrogenase reductase is a dimer of two identical subunits.

3. Dinitrogenase is a ____________
a) Monomer
b) Dimer
c) Trimer
d) Tetramer
View Answer

Answer: d
Explanation: Dinitrogenase is a tetramer with two copies of two different subunits, containing both iron and molybdenum.
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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

Answer: d
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

Answer: a
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

Answer: a
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

Answer: a
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 nitrification.
Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called denitrification.
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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

Answer: d
Explanation: Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called nitrification.
Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called 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 ____________
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation
View Answer

Answer: b
Explanation: Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called 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 nitrogen assimilation.
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10. Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called ____________
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation
View Answer

Answer: c
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 nitrogen assimilation.
Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called nitrification.

Sanfoundry Global Education & Learning Series – Biochemistry.

To practice all areas of Biochemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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