However, in the form of N2, nitrogen is unusable by all organisms except for a few primitive bacteria that are capable of converting N2 gas to ammonia (NH3). This process of conversion is called nitrogen fixation, and makes the nitrogen available for use by organisms.
1 Simple carbohydrates have very simple chemical structures and are made of small molecules. 2  Complex carbohydrates have very complex structures while the molecules are large, unlike simple carbohydrates.
They can range from complex carbohydrates to simple carbohydrates. The simplest form of carbohydrates are monosaccharides. Monosaccharides are the simplest units of carbohydrates and the simplest form of sugar. They are the building blocks of more complex carbohydrates such as disaccharides and polysaccharides.Physically, they are usually colorless, can dissolve in water and have the appearance of a crystal-like substance.hey can range from complex carbohydrates to simple carbohydrates. The simplest form of carbohydrates are monosaccharides. Monosaccharides are the simplest units of carbohydrates and the simplest form of sugar. They are the building blocks of more complex carbohydrates such as disaccharides and polysaccharides.