Question

Most of the plants absorb nitrogen in one of the following forms. This is ______.

Options

• proteins

• nitrates and nitrites

• urea

• atmospheric nitrogen

Answer 1

Most of the plants absorb nitrogen in one of the following forms. This is nitrates and nitrites.

Explanation:

Although nitrogen makes up about 78% of the Earth’s atmosphere, green plants cannot absorb or use gas-phase atmospheric nitrogen directly because of its exceptionally strong chemical bonds. Instead, soil bacteria (such as Rhizobium or nitrifying bacteria) must convert gas into soluble inorganic compounds through nitrogen fixation. Plants then absorb these dissolved nitrates \[\ce{NO^-_3}\] and nitrites \[\ce{NO^-_2}\]  from the soil through their roots to manufacture essential proteins and amino acids.