in college) or biology are lipids, carbohydrates, nucleic acids, and proteins. All
of these biomolecules are carbon compounds, and each of them is characterized
by different functional groups, which gives them different functions in the
human body.
Lipids
Lipids are made up of carbon, hydrogen, and oxygen atoms, connected in long
branching chains. The most common examples of lipids are fats and oils. One
group of lipids commonly talked about in biology is the triglycerides.
Triglycerides are made up of three long fatty acid chains (long hydrocarbon
chains) attached to a head group that consists of a molecule of glycerol. (No
need to know the structure of glycerol for the test.) The molecules that make up
cell walls are a type of lipid, specifically known as phospholipids. And one final
note about lipids: Lipids are not water-soluble and tend to aggregate to form
droplets when placed in water.
Carbohydrates
Carbohydrates are also known as sugars; they are organic compounds that
contain carbon, hydrogen, and oxygen, usually in a ratio of 1:2:1. They are
polymers made up of sugar monomers. Some simple types of carbohydrates are
glucose and fructose, for example. Both of these are examples of
monosaccharides, carbohydrates made up of just one unit of sugar. Larger
sugars, called polysaccharides, are the energy storage units in both plants and
animals—the storage carbohydrate of animals is glycogen, and the storage
carbohydrate of plants is cellulose. Carbohydrates can be straight chains of these
sugar monomers, or they can be extensively branched.
Nucleic Acids
Nucleic acids contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. They
are polymers made up of monomers known as nucleotides. There are two major
nucleic acids: DNA (which you’ve probably heard of, stands for
deoxyribonucleic acid) and RNA (you might have heard of this type of nucleic
acid, too—ribonucleic acid). DNA is the genetic material of all living things; it
contains the blueprints for all life.