I recently started to review my organic chemistry binder to prep myself for the upcoming semester. While they may be unique in doing so, Smith splits up the two semesters of organic, with the long summer break in between. In other words, students take organic one in the spring, and then, almost four months later, are expected to jump enthusiastically back into the subject for the second and final semester the next fall.

Because I learn best by teaching others, I decided to draft a post involving some chemistry. Don’t worry; I don’t go much into detail and have taken care to pick a topic that shouldn’t bore you to tears– saturated and unsaturated fats.

As you likely know, fats, or fatty acids, can be divided into the categories of saturated and unsaturated. Saturated fats are solid at room temperature and include butter and lard, while unsaturated fats are liquids at room temperature, like olive or canola oil.

Pictured is an unsaturated fatty acid, which can be identified from its double bonds, the two sets of double lines at opposites ends of the molecule.

Par contre, below is a saturated fatty acid, “saturated” because it is comparatively loaded (or saturated) with hydrogens, the many H’s present in the molecule. You see, carbon likes to have four bonds, or four electrons, to call its own. A double bond can satisfy two of these four electrons, or the carbon can alternately get its fill of four electrons via, for example, two single bonds to two carbon atoms and two single bonds to two hydrogen atoms, as illustrated below.

While the molecule pictured retains one double bond between the C (carbon) and O (oxygen), it lacks the second double bond of the unsaturated fatty acid. Saturated fatty acids thus lack the multiple double bonds that are the trademark of unsaturated fatty acids.

Unsaturated fatty acids with a single double bond are known as monounsaturated fatty acids. An unsaturated fatty acid with multiple double bonds is called a polyunsaturated fatty acid, from poly, meaning more than one.

What is the significance of these double bonds?

If you look back at the first image of an unsaturated fatty acid, you will notice that the molecule’s double bond creates a sort of “kink,” bending the structure. The saturated fatty acid is in contrast straight in orientation, which makes it perfectly adept at packing together and wedging itself into your arteries. That’s why saturated fats (bacon grease, Crisco, etc.) are said to clog your arteries, and lead over time to an increased risk of heart disease.

There. All done. No more chemistry coming your way for a good while. So take a breather, and let me know what you think of my chemistry lesson.

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