organic molecule

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Definition of organic molecule

A molecule of the kind normally found in living systems. Organic molecules are usually composed of carbon atoms in rings or long chains, to which are attached other atoms of such elements as hydrogen, oxygen, and nitrogen.

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The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


What is an organic molecule?

An organic molecule is a complex molecule that is primarily made of carbon atoms bonded with other elements and/or other carbon atoms. All living things on Earth are composed of organic molecules.

A molecule is a group of atoms bonded together. Organic is an adjective that refers to compounds containing carbon, or, more broadly, to living organisms.

Organic molecules are essentially the “building blocks” of life because every living thing (plant or animal) is made of organic molecules and usually needs to consume other organic molecules to live. Organic molecules are responsible for the DNA and RNA in animals and plants.

Why are organic molecules important to life?

Because life as we know it cannot exist without organic molecules, scientists have logically concluded that organic molecules must predate life itself, perhaps originating more than 4 billion years ago. In the 1800s, chemists (such as Jöns Jakob Berzelius and Friedrich Wohler) pioneered the field of organic chemistry (the study of carbon compounds). Organic chemists determined that it is the presence of carbon that differentiates living matter from nonliving matter.

Simply put, an organic molecule is a complex molecule that contains the element carbon bonded with other elements. Carbon is an incredibly versatile element that can form bonds with many other elements, such as hydrogen, oxygen, and nitrogen—or other carbon atoms—to form huge carbon chains.

Living organisms are dependent on four types of organic molecules:

  • Nucleic acids (DNA and RNA), which store genetic information in cells.
  • Lipids (such as fats), which perform a wide variety of tasks, ranging from supplying energy to transporting chemical messages.
  • Carbohydrates, which are a primary source of energy for both animal and plant cells.
  • Proteins, which are responsible for a wide range of vital life processes.

Organic molecules (which always include carbon) are so important to living organisms that life itself is said to be carbon-based. No life exists on Earth that doesn’t contain organic molecules. The possibility of alien life that is based on something else is a popular subject of scientific speculation and science fiction.

Inorganic molecules, such as carbon dioxide, are much less complex than organic molecules and are rarely found in living things.

Did you know ... ?

Newly identified organic molecules are sometimes given interesting names. In 2008, a group of Japanese scientists identified an eye protein that they named Pikachurin, after the character Pikachu from the video game series Pokémon. And that wasn’t even the first protein named after a video game character! A particularly spiky protein discovered in the 1980s was named Sonic Hedgehog protein.

What are real-life examples of organic molecules?

Organic molecules aren’t just in our bodies and the food we eat—they’ve also been found on Mars!


What other words are related to organic molecule?

Quiz yourself!

____ is the central element in organic molecules because it can easily bond with many other elements like hydrogen and even itself to form long chains.

How to use organic molecule in a sentence