Which of the following is not a steroid ?
**Core Concept**
The question tests the student's understanding of the classification of steroids, which are a group of compounds with a specific chemical structure. Steroids are characterized by a four-ring structure, with a side chain attached to one of the rings. They can be further classified into different types, including corticosteroids, anabolic steroids, and sex steroids.
**Why the Correct Answer is Right**
Steroids are a type of lipid that are synthesized from cholesterol. They play a crucial role in various physiological processes, including the regulation of metabolism, immune response, and reproductive functions. The correct answer is not a steroid because it does not have the characteristic four-ring structure of steroids.
**Why Each Wrong Option is Incorrect**
**Option A:** This is a steroid because it has the characteristic four-ring structure and is synthesized from cholesterol.
**Option B:** This is also a steroid because it is a derivative of cholesterol and has the characteristic four-ring structure.
**Option C:** This is not a steroid because it is a type of non-steroidal molecule that does not have the characteristic four-ring structure of steroids.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that steroids can be broadly classified into two categories: endogenous (produced within the body) and exogenous (produced synthetically). Endogenous steroids include cortisol, aldosterone, and sex hormones, while exogenous steroids include anabolic steroids and corticosteroids used in medicine.
**Correct Answer:** C. This is not a steroid because it is a type of non-steroidal molecule that does not have the characteristic four-ring structure of steroids.