Steroid

Definition

Steroids are a class of lipids characterized by a four-ring carbon structure. They play vital roles in cell membrane structure and signaling pathways.

5 Must Know Facts For Your Next Test

1. Steroids are synthesized from cholesterol in eukaryotic cells.
2. They function as signaling molecules that regulate a variety of physiological processes.
3. Steroid hormones include cortisol, estrogen, and testosterone.
4. The rigid structure of steroids contributes to the fluidity and stability of cell membranes.
5. In microbiology, some bacteria can degrade steroids, utilizing them as a carbon source.

Review Questions

• What is the basic structural characteristic that defines steroids?
• Name two physiological roles of steroid hormones.
• How do steroids contribute to cell membrane properties?

Related terms

Cholesterol: A type of lipid that is a precursor to steroid hormones and an important component of cell membranes.

Phospholipids: Lipids that form the bilayer of cell membranes, consisting of two fatty acids, a glycerol unit, and a phosphate group.

Lipid Bilayer: A double-layered arrangement of phospholipids and cholesterol that forms the structural basis of all cell membranes.