How Do Macromolecules Form? — Overview & Process

Biological Polymers

You're probably familiar with polymers such as plastics and Styrofoam, but a lot of organic molecules are polymers too.

Macromolecules are large, complex, biological molecules and most of them are polymers. Monomers link up in a specific order during a process called polymerization. This allows them to create biological polymers like starches and complex sugars.

There are four major classes of biological macromolecules:

• Lipids are formed through fatty acid synthesis.

• Carbohydrates are formed through dehydration synthesis.

• Proteins are formed through translation.

• Nucleic acids are formed through dehydration synthesis.

It's important to note that polymerization is normally performed by enzymes (which are actually proteins) in the body. How weird is that? A polymer that makes other polymers.

Back to the main idea though. Monomers are perfectly happy to be by themselves. It costs a bit too much energy to polymerize by themselves, so they never really try to. However, enzymes make it more efficient for polymers to form. They basically stick the pieces of the polymer together manually.

$$\color{#8925AE}{\text{Vocabulary Review:}}$$

$\color{#8925AE}{\text{Monomer}}$ : Any molecule that can react with other molecules of the same or different makeup to form a chain, or polymer

$\color{#8925AE}{\text{Polymer}}$ : A chain of monomers made of a specific type of compound

$\color{#8925AE}{\text{Macromolecule}}$ : A polymer that has a large (macro) molecular mass. There are four main types in organisms: carbohydrates, proteins, lipids, and nucleic acids

$\color{#8925AE}{\text{Polymerization}}$ : Enzymes link up monomers in a specific order, creating a polymer

What Are Macromolecules?

Before we talk about how these large molecules form, let's have a quick refresher on what exactly they are.

Much of our focus in biology is on the four main types of macromolecules: proteins, carbohydrates, lipids (fats), and nucleic acids.

Macro is the opposite of micro, so it literally denotes largeness. A good way to remember that macromolecules are large is to think "Big Mac". ("Mac" sounds like macro, and "Big" reminds us that they are large.)

Another word for macromolecule is polymer. They are synonyms. Proteins, lipids, carbohydrates, and nucleic acids are all examples of polymers.

Polymers are made from smaller repeating units that are all linked together by covalent bonds. These smaller molecules are called monomers.

Let's return quickly to the four molecules we mentioned above. Each of them is made of a different monomer. Each of those monomers has its own name.

So, How Do Polymers Form?

Polymers form when monomers bond together. This process is called synthesis.

The specifics of each synthesis reaction vary with the types of monomers and polymers involved. However, the general idea is the same: monomers bond together to make a polymer. This is done with the help of enzymes that catalyze specific reactions.

Nucleic acids, carbohydrates, and proteins all form through dehydration synthesis.

Think about when you're dehydrated (like the lady in the picture above). You feel dehydrated when you've lost a lot of water.

The same thing is true in dehydration synthesis. Monomers are joined together ("synthesis") as they lose water molecules ("dehydration").

Key Vocabulary:

1. Polymer
2. Monomer
3. Polymerization
4. Dehydration
5. Synthesis

(Video) Biomolecules

by Amoeba Sisters

Watch this video by the Amoeba Sisters to learn about the monomers that combine to make up more complex biological units. Here's a summary of what the different biomolecules are made of:

• Carbohydrates are things like sugars and starch. They are made of monosaccharides.

• Lipids are also known as fats. They are made of fatty acids and glycerol.

• Proteins are made of amino acids.

• Nucleic acids are things like the famous double helix, DNA, and its single-stranded relative, RNA, which store genetic information. They are made of nucleotides. These nucleotides help make up the base pairs found in DNA and RNA.

All the biomolecules are made up of carbon atoms, hydrogen atoms, and oxygen atoms. Additionally, proteins also contain nitrogen, and nucleic acids have both nitrogen and phosphorous atoms.