Question

What is the only type of Nitrogen compound that plants can use to build proteins?

Answer 1

Ammonium (NH₄⁺) is the only type of nitrogen compound that plants can directly utilize to build proteins.

Step-by-step explanation:

Ammonium (NH₄⁺) is the form of nitrogen that plants can efficiently absorb and assimilate for protein synthesis. Nitrogen, an essential component for plant growth, is often available in various forms in the soil, including nitrate (NO₃⁻) and ammonium. However, plants primarily rely on ammonium as the preferred source for nitrogen assimilation.

Plants have specific transport systems that facilitate the uptake of ammonium ions through their root systems. These ions are then incorporated into amino acids, the building blocks of proteins, through various metabolic pathways. Amino acids derived from ammonium are further utilized in the synthesis of diverse proteins crucial for plant development, including enzymes, structural proteins, and signaling molecules.

While plants can utilize other nitrogen compounds like nitrates, they need to convert them into ammonium through processes like nitrate reduction before incorporating them into amino acids. This conversion involves energy expenditure and multiple enzymatic steps, making direct uptake of ammonium a more efficient pathway for plants to acquire nitrogen for protein synthesis.

In essence, ammonium serves as the primary nitrogen compound that plants directly incorporate into proteins, ensuring their growth, development, and overall physiological functions. This preference for ammonium underscores its significance as a key nutrient for plant life.

Answer 2

Plants can only use 'fixed' nitrogen compounds, such as nitrates, ammonium ions, and ammonia, to build proteins. This is a result of biological nitrogen fixation, where bacteria convert atmospheric nitrogen into a form plants can assimilate.

Step-by-step explanation:

The only type of Nitrogen compound that plants can use to build proteins is in the "fixed" form. This means that the inert diatomic nitrogen gas (N₂) from the atmosphere must be converted into compounds such as nitrates (NO₃−), ammonium ions (NH₄+), and urea (NH₂₂CO). Through a process known as biological nitrogen fixation (BNF), certain soil bacteria and cyanobacteria are able to fix atmospheric nitrogen and convert it to ammonia (NH₃), which plants then assimilate to make amino acids and subsequently proteins. This process is especially common in legumes, like peas and beans, which have a symbiotic relationship with nitrogen-fixing bacteria called rhizobia in their root nodules.