Biological Nitrogen Fixation and Assimilation

The video explains nitrogen fixation, a process carried out by prokaryotes or bacteria known as nitrogen fixers. These organisms use the enzyme nitrogenase to convert atmospheric nitrogen into ammonia. Nitrogen fixation can be free-living, symbiotic, or associative. The video details the symbiotic relationship between plants and bacteria, such as Rhizobium, which form root nodules. The chemical process involves several steps, including the formation of diamide and hydrazine, leading to ammonia production. Ammonia is then used in amino acid biosynthesis through reductive amination and transamination.

Which of the following is an example of a free-living nitrogen-fixing bacterium?

• Frankia

• Rhizobium

• Azospirillum

• Azotobacter

What is the first step in the formation of root nodules in leguminous plants?

• Infection thread formation

• Bacteroides formation

• Rhizobia attraction to root hair

• Symbiosome development

Which protein protects nitrogenase from oxygen?

• Cytochrome

• Hemoglobin

• Leghaemoglobin

• Myoglobin

What is the final product of nitrogen fixation before it is converted to amino acids?

• Diamide

• Hydrazine

• Ammonium ion

• Nitrogen gas

In reductive amination, which acid combines with ammonium ion to form glutamic acid?

• Alpha-ketoglutaric acid

• Citric acid

• Pyruvic acid

• Oxaloacetate

Which enzyme is involved in the transamination process?

• Peptidase

• Glutamate dehydrogenase

• Aspartate aminotransferase

• Nitrogenase

What is the role of transaminases in amino acid biosynthesis?

• Convert ammonia to ammonium ion

• Bind oxygen to nitrogenase

• Transfer amino groups between molecules

• Catalyze the reduction of nitrogen