Monomer Definition

A monomer is a small molecule that reacts with an identical molecule to form a larger molecule. It is the smallest unit in a macromolecule, which is also known as a polymer.

The word monomer derives from the Greek prefix monos- which means “single” or “only.”

Examples of Monomer

Monosaccharides – The Most Accessible Energy

Carbohydrates are macronutrient polymers that must be broken into smaller units, called monosaccharides, before being used for energy. Monosaccharides, along with glucose and fructose, are part of a larger group of isomers.

Monosaccharides typically only form bonds with other monosaccharides, and are released into the body through a process called glycolysis. Glycolysis is the only process needed to break down carbohydrates to turn them into energy, making monosaccharides the most readily-accessible form of energy.

Fatty Acids – A Multi-Step Process

Fatty acids do not provide energy as immediately as monosaccharides, because they bond with carbon and hydrogen atoms. These stronger bonds require three processes to achieve isolation. During the first process, lipolysis, fats are stored in the body’s adipose tissue. From there, they undergo activation, during which they move to the mitochondria. The mitochondria then oxidize the fatty substances, isolating fatty acids for energy.

Fatty acids, like monosaccharides, are monomers that, absorbed through food, provide energy to the body. However, as shown by the more intense process that fatty acids undergo, monomers rely on several diverse paths to achieve isolation.


As shown by fatty acids in Example #2, monomers do not form exclusive bonds even though their basic definition signifies a bond between numerous units. Typically, they bond with other monomers to create larger units.

Silicone, a sealing material used in construction and electronics, is an example. This material, also called polysiloxanes, consists primarily of alternating silicon atom monomers and oxygen atom monomers. However, when paired with carbon monomers and/or hydrogen monomers, it becomes more resistant, more durable, and less combustible.

From this comes evidence that monomers, while able to create “pure” polymers, can also be combined with other isomers to create materials that do not occur in nature.

Related Biology Terms

  • Polymer – Also known as a macromolecule, a molecule that results from the pairing of one or more monomers.
  • Isomer – A monomer or chemical compound that has the same chemical formula as other monomers or chemical compounds, but a different number of electrons.


1. Monomers are the smallest unit of:
A. A polymer
B. A macromolecule
C. An isomer
D. Both A and B

Answer to Question #1

2. Monomers are ________, but some monomers take a longer process to isolate than others.
A. Micellar
B. Wine cellar
C. Unicellular
D. Unicyclical

Answer to Question #2

3. Monomers sometimes exist as isomers, which means:
A. They have a different chemical compound than any other existing monomer.
B. They have the same chemical formula as other monomers.
C. The have the same chemical compound as other monomers.
D. They cannot bond with any other monomer.

Answer to Question #3

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