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.
There are two types of carbohydrates, simple and complex. Simple carbohydrates are sugars made of one or two units or molecules. Words that end in âoseâ are sugars. Sugars are sucrose also known as table sugar, fructose, which is the natural sugar found in fruit and honey, and lactose, which is the sugar found in milk.