Chapter 24, Problem 1P

Interpretation Introduction

Interpretation:

Enzymes that are required in nitrogen fixation should be determined.

Concept introduction:

Nitrogen fixation is the process by which the molecular nitrogen of the atmosphere is converted into ammonia or other nitrogenous compounds. Atmospheric nitrogen is unreactive and metabolically useless, so to make it useful, microorganisms convert it into useful nitrogenous compounds. Nitrogen fixation occurs between the termite and fungi.

Answer to Problem 1P

Option (a), Nitrogenase, and option (c), Reductase are the correct answer.

Explanation of Solution

Reason for correct option:

Option (a) is nitrogenase. Nitrogenase is the metalloenzyme that is involved in the conversion of molecular nitrogen into ammonia during the nitrogen fixation process. Hence, this option is correct.

Option (c) is reductase. In the nitrogen fixation process, the nitrate reductase enzyme is used to reduce nitrate into nitrite. This reaction is the nitrate assimilation process and the rate-limiting step in nitrogen fixation. Hence, this option is correct.

Conclusion

Reasons for incorrect options:

Option (b) is glutamine synthetase. Glutamine synthetase is a mitochondrial enzyme that catalyzes the formation of glutamine. During this process,the amide bond is formed between the ammonia and glutamate. This enzyme is mostly found in liver, kidney, and brain cells, and has no relation with nitrogen fixation. Hence, this option is incorrect.

Option (d) is glutamate dehydrogenase. This enzyme is involved in the interconversion of glutamate to alpha-ketoglutarate and ammonia. It is mostly found in liver, brain, pancreas, and kidney cells.