Steroids

Steroids are one type of lipid that you have probably heard of. Chemicals such as the bile acids, the male and female sex hormones, cortisone and cholesterol are all steroids.

What steroids have in common is that they are all derived from a polycyclic four-ring structure that is shown here (and also in Example 2 in your workbook). With each corner in this structure representing a carbon atom that has enough hydrogen atoms to bring it to a total of four bonds, I think you can see that this molecule and those derived from it should be hydrophobic. They would be quite nonpolar and insoluble in water, for the most part.

Structure of steroid precursor. [66str01.JPG]

Here (also shown in Example 2 in your workbook) is the structural formula for cholesterol, which is the most abundant of the steroids. Cholesterol is associated with atherosclerosis, but it also serves some important positive functions in the body also. It is associated with cell membranes and their proper functioning, and it also serves as a precursor to other steroids, such as vitamin D, the bile salts that are used in digesting fat and also and various steroid hormones as well.

Structure of chloesterol. [66str02.JPG]

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