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.
1. Simple Carbohydrates: Simple carbohydrates have a simple molecular structure and are made up of 1 or 2 sugar molecules. These are carbs laden foods that can be digested easily by the system due to their simple structure. On consumption, these sugars are quickly absorbed by the body in the form of glucose.