What property of ammonia makes it significant in biological processes?

Ammonia's significance in biological processes largely stems from its basicity. As a weak base, ammonia can accept protons (H+) in solution, which plays a crucial role in biological buffering systems. This is important because maintaining pH within specific ranges is essential for the proper functioning of enzymes and various cellular processes. In many biochemical reactions, ammonia can interact with different compounds, facilitating the transport and transformation of nitrogen in biological systems.

While the other properties of ammonia, such as acidity, stability, and volatility, are also relevant in different contexts, they do not encapsulate the key role ammonia plays in biological systems to the extent that its basicity does. For instance, while ammonia can act as an acid in some reactions, its predominant and impactful behavior in most biological scenarios is as a base, enabling it to participate actively in metabolic processes, including nitrogen assimilation in plants and the urea cycle in animals.