AP BIOLOGY

Detailed explanation-1: -Nitrates in the soil are a primary source of nitrogen which is essential for plant growth. Under normal conditions nitrates are converted to protein in the plant at about the same rates as they are absorbed into the root system.

Detailed explanation-2: -As nitrate is assimilated via conversion to nitrite, then ammonium into amino acids, it has been suggested that the internal pools of amino acids within plants may indicate nitrogen status by providing a signal that can regulate nitrate uptake by the plant.

Detailed explanation-3: -Plants require nitrogen in the form of nitrate ions absorbed by the roots to make amino acids, chlorophyll and nucleotides.

Detailed explanation-4: -Nitrogen is an essential element for all forms of life and is the structural component of amino acids from which animal and human tissues, enzymes, and many hormones are made. For plant growth, available (fixed) nitrogen is usually the limiting nutrient in natural systems.