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.
Simple carbohydrates include monosaccharides (one-unit sugars) and disaccharides (two-unit sugars). Monosaccharides include glucose, fructose and galactose. These can be absorbed directly and don't require further breakdown from enzymes, unlike disaccharides and polysaccharides.s a dietitian, I'm often asked to explain the difference between simple and complex carbohydrates. While most people have heard that complex carbohydrates are better for you than simple carbohydrates, what's often unclear is how the two differ, and why the differences between the two affect your health.