Organic compounds are called "organic" because they are associated with living organisms. These molecules form the basis for life. They are studied in great detail in the chemistry disciplines of organic chemistry and biochemistry.
There are four main types or classes of organic compounds that are found in all living things. These are carbohydrates, lipids, proteins, and nucleic acids. In addition, there are other organic compounds that may be found in or produced by some organisms. All organic compounds contain carbon, usually bonded to hydrogen. Other elements may also be present.
Let's take a closer look at the key types of organic compounds and see examples of these important molecules.
Carbohydrates — Organic Compounds
Carbohydrates are organic compounds made of the elements carbon, hydrogen, and oxygen. The ratio of hydrogen atoms to oxygen atoms in carbohydrate molecules is 2:1 Organisms use carbohydrates as energy sources, structural units, as well as for other purposes. Carbohydrates are the largest class of organic compounds found in organisms.
Carbohydrates are classified according to how many subunits they contain. Simple carbohydrates are called sugars. A sugar made of one unit is a monosaccharide. If two units are joined together, a disaccharide is formed. More complex structures form when these smaller units link to each other to form polymers. Examples of these larger carbohydrate compounds include starch and chitin.
Sugar cubes are blocks of sucrose, a carbohydrate.
Carbohydrate Examples:
Lipids — Organic Compounds
Canola oil is an example of a lipid. All vegetable oils are lipids.Lipids are made of carbon, hydrogen, and oxygen atoms.Lipids have a high hydrogen to oxygen ratio than is found in carbohydrates. The three major groups of lipids are triglycerides (fats, oils, waxes), steroids, and phospholipids. Triglycerides consist of three fatty acids joined to a molecule of glycerol. Phospholipids resemble triglycerides except there is a phosphate group in place of one of the fatty acid chains.
Lipids are used for energy storage, to build structures, and as signal molecules to help cells communicate with each other.
Lipid Examples:
- cholesterol
- paraffin
- olive oil
- margarine
- cortisol
- estrogen
- phospholipid bilayer that forms the cell membrane.
Proteins — Organic Compounds
Muscle fibers, such as those found in meat, consist mainly of protein.
Proteins consist of chains of amino acids called peptides. Peptides, in turn, are made of chains of amino acids. A protein may be made from a single polypeptide chain or may have a more complex structure where polypeptide subunits pack together to form a unit. Proteins consist of hydrogen, oxygen, carbon, and nitrogen atoms. Some proteins contain other atoms, such as sulfur, phosphorus, iron, copper, or magnesium.
Proteins serve many functions in cells. They are used to build structure, catalyze biochemical reactions, for immune response, to package and transport materials, and to help replicate genetic material.
Protein Examples:
- Enzymes
- Collagen
- Keratin
- Albumin
- Hemoglobin
- Myoglobin
- Fibrin
Nucleic Acids — Organic Compounds
DNA and RNA are nucleic acids that code genetic information.
A nucleic acid is a type of biological polymer made up of chains of nucleotide monomers. Nucleotides, in turn, are made up of a nitrogenous base, sugar molecule, and phosphate group. Cells use nucleic acids to code the genetic information of an organism.
Nucleic Acid Examples:
- DNA (deoxyribonucleic acid)
- RNA (ribonucleic acid)
Other Kinds of Organic Compounds
This is the chemical structure of carbon tetrachloride, an organic solvent.
In addition to the four main kinds of organic molecules found in organisms,
there are many other organic compounds. These include solvents, drugs, vitamins, dyes, artificial flavors, toxins, and molecules used as precursors to biochemical compounds. Here are some examples:
- Acetaldehyde
- Acetaminophen
- Acetone
- Acetylene
- Benzaldehyde
- Biotin
- Bromophenol blue
- Caffeine
- Carbon tetrachloride
- Fullerene
- Heptane
- Methanol
- Mustard gas
- Vanillin.
