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 are often used as building blocks of larger, complex carbohydrates. 2  The empirical structure of simple carbohydrate is C 6 H 12 O 6 or (CH 2 O) 6 while that of complex carbohydrate is (C 6 H 10 O 5) n, in which ânâ is the number of monomer units.
Simple Sugars. Simple sugars are another characteristic of carbohydrates. Also called monosaccharides, simple sugars include fructose, glucose and galactose. Fructose is often found in fruit, whereas galactose is found in milk. Both are converted to glucose by the liver. Glucose is the body's energy source.omplex Carbohydrates. Carbohydrates also are characterized by the presence of complex carbohydrates. Complex carbohydrates are composed of chains of sugar linked together. Amylose is a common sugar found in complex carbohydrates.