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What are Macromolecules?


Unlike small, simple molecules such as water or carbon dioxide, macromolecules are enormous molecules that contain thousands of atoms (or more!). They are still considered molecules because they cannot be broken up into smaller, simpler pieces without losing the properties of the whole.


You can think of macromolecules as a chain made of metal links. The chain could be broken down into individual links, but then it would no longer function as a chain. In this metaphor, the links of the chain are the monomers, or subunits, that make up a macromolecule.


There are four main macromolecules that are important for living things. The first macromolecule is probably familiar to you: Carbohydrates. Carbohydrates are what our bodies burn to make energy. Some carbohydrates, like glucose and fructose, are relatively simple and short, so our body can break them down quickly. This is why eating sugary foods may give you a quick “sugar rush” followed by a crash when your body runs out of energy. Other more complex carbohydrates, like starch and glycogen, take longer to break down and will give you a slow release of energy over time.


Lipids are another macromolecule that is vital for life; they form things like fats, oils, waxes, and steroids. Lipids are made up of monomers called fatty acids, which are non-polar. As a result, lipids are the only non-polar macromolecule on our list, which means that they repel water rather than mixing with it (this is why the oil and water in salad dressing always separate from each other). Our bodies use lipids to store energy in the form of fat and to make up cell membranes.


The next biologically important macromolecule is protein. The monomers that make up proteins are called amino acids. Proteins are especially important macromolecules, because they make up the enzymes that allow our body to build and break down the other four macromolecules. In addition to enzymes, proteins are also used to build hormones like insulin, which carry chemical signals through our bodies.














Our final macromolecule is nucleic acids. Nucleic acids are part of the DNA and RNA that make up our genetic code. Monomers called nucleotides make up nucleic acids. DNA and RNA are each built from four types of nucleotides, and our genetic information is “recorded” in the order of these nucleotides in sequence.


While fad diets may tell us that fats or carbohydrates are bad for us, the reality is that all of these macromolecules are vital for the functioning of our cells, our brain, and our entire bodies.




Image Citation:


PublicDomainPictures (artist). (2013).DNA Biology Science [digital art]. Retrieved from

dna molecule.jpg
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