In chemistry, what does it mean to be organic?

 

In chemistry, what does it mean to be organic?

At a minimum, these molecules need carbon. But that’s only the first requirement

t of 118 elements, only one has its own field of study: carbon. Chemists refer to most molecules that contain one or more carbon atoms as organic. The study of these molecules is organic chemistry.

Carbon-based molecules get special attention because no other element comes close to carbon’s versatility. More types of carbon-based molecules exist than all non-carbon ones put together.

Scientists generally define a molecule as organic when it contains not only carbon, but also at least one other element. Typically, that element is hydrogen, oxygen, nitrogen or sulfur. Some definitions say that a molecule must contain both carbon and hydrogen to be organic.

(By the way, in farming, “organic” refers to crops grown without certain pesticides and fertilizers. That use of “organic” is very different from the chemical definitions here.)

Living things are built with organic molecules and operate using organic molecules. Indeed, organic molecules perform the tasks that makes a living thing “alive.” 

DNA, the molecular blueprint for our bodies, is organic. The energy we get from food comes from breaking down carbon-based — organic — molecules. In fact, until the 1800s, chemists thought that only plants, animals and other organisms could make organic molecules. Now we know better. Our oceans created organic molecules before life even existed. Organic molecules can also be made in the lab. Most medicines are organic. So are plastics and most perfumes. Still, organic molecules are seen as a defining feature of life-forms.

But living things also contain lots of molecules that are not organic. Water is a good example. It makes up about six-tenths of our bodyweight but is not organic. We must drink water to live. But drinking water doesn’t satisfy hunger. A hamburger or beans, for instance, contains those organic molecules needed to fuel our bodies’ growth.

In living things, organic molecules usually fall into one of four categories: lipids (such as fats and oils), proteins, nucleic acids (such as DNA and RNA) and carbohydrates (such as sugars and starches). These molecules can get big, though still too small to see with just our eyes. Some may even be organic molecules bonded to other organic molecules. The big ones, made by linking a lot of littler ones, are known as polymers.