The four main classes of organic compounds (carbohydrates,
lipids, proteins, and nucleic acids) that are essential to the proper
functioning of all living things are known as polymers or
macromolecules. All of these compounds are built primarily of carbon,
hydrogen, and oxygen but in different ratios. This gives each
compound different properties.
Carbohydrates are used by the body for energy and structural
support in cell walls of plants and exoskeletons of insects and
crustaceans. They are made of smaller subunits called
nionosaccharides. Monosaccharides have carbon, hydrogen, and oxygen
in a 1:2:1 ratio. Monosaccharides or simple sugars include glucose,
galactose, and fructose. Although their chemical formulas are the
same, they have different structural formulas. These simple sugars
combine to make disaccharides (double sugars like sucrose) and
polysaccharides (long chains like cellulose, chitin, and glycogen). Color
code the glucose molecule on this worksheet (carbon-black, hydrogenyellow,
and oxygen-red). Use your textbook to help draw the
structural formulas for fructose and galactose:
