Macromolecule Definition

Macromolecules are large, complex molecules. They are usually the product of smaller molecules, like proteins, lipids, and carbohydrates.

Another name for a macromolecule is a polymer, which derives from the Greek prefix poly- to mean “many units.” In broken-down terms, a macromolecule is the product of many smaller molecular units.

Examples of Macromolecules

Example #1: Energy from Carbohydrates

The small molecular units that make up macromolecules are called monomers. Monomers are usually single-celled, and isolated after a polymer, or macromolecule, is broken down in a chemical process.

Metabolism, or the conversion of food into energy, is the most common of these chemical processes. When you metabolize food, your body breaks the macromolecules found within the food into smaller units, which are then used to propel the body through the day.

Carbohydrates constitute one of the most-studied macromolecules in biology. Simple or complex, they yield glucose, or “blood sugar,” as their primary energy unit. Furthermore, both simple and complex carbohydrates are, at the most basic level, chains of glucose molecules.

Metabolizing carbohydrates, therefore, necessitates that the body break down these glucose chains. The body does so by releasing enzymes, like amylase, which adhere to the glucose chains to detach them and isolate the glucose molecule. This process culminates in the macromolecule’s yielding energy, as well as small amounts of H2O and CO2, for the body to consume.

Example #2: Synthetic Fibers

Shopping for new clothes is a pass-time for some, and torture for others. Regardless of how you feel about shopping, however, you have probably encountered synthetic garments. Nylon, rayon, and Spandex among the most well-known, these non-breathable fabrics consist almost entirely of macromolecules.

We will examine Spandex more closely to better understand the macromolecular qualities of synthetic fibers. The first step in creating Spandex fiber involves reacting monomers to make a prepolymer, or a liquid, primitive macromolecule. Next, in a process called “spinning” these prepolymers are fed through a cell to solidify and attain a desired thickness. Nylon and rayon, although chemically different, are manufactured using similar techniques.

To relate to other concepts, Spandex and other synthetic fabrics are created using a process diametrically opposed to metabolism: rather than its macromolecular structure being broken down, it is built from smaller components.

Example #3: Genetic Transfer

As surprising as it seems, deoxyribonucleic acid (DNA) is technically a set of macromolecules. The nucleic acids (A, T, C, and G) that act as codes for genetic material are made of monomers called nucleotides, which also carry genetic materials.

DNA separates during meiosis, or sex cell formation. Since the macromolecular structure is no longer whole, the monomers that remain, the nucleotides, become responsible for carrying genetic information into the gametes, or sex cells, that result.

Two tie this example to those that precede it, DNA is a macromolecule that functions at first like a carbohydrate, and then like a synthetic fabric. The body first breaks it down into its smallest functional element, the monomer nucleotide, to rebuild it, if fertilized, into another mass of macromolecules.

Related Biology Terms

  • Polymer – A linked group of monomers. If particularly large, these groups repeat in series.
  • Monomer – The simplest unit of a polymer.
  • Prepolymer – A molecular unit reduced to the degree that it can be manipulated before polymerization.


1. Macromolecules are called polymers because …
A. … they are made of many components.
B. … they practice polyamory.
C. … they attach to polyurethane.
D. … they are made of many vitamins.

Answer to Question #1

2. DNA is considered a macromolecule because it is made of many _________, called _________.
A. Misnomers, high tides
B. Monomers, nucleotides
C. Monomers, nuclei
D. Polymers, nucleotides

Answer to Question #2

3. How is a prepolymer different from a monomer?
A. Prepolymers and monomers are the same.
B. Prepolymers contain more genetic information than monomers when inserted into the cell.
C. Prepolymers are more complex than a monomer, but less solidly-constructed than a true polymer.
D. Prepolymers are less complex than a monomer and can dramatically change the chemical nature of a polymer.

Answer to Question #3

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