USA Biology Olympiad (USABO) Practice Exam

What mechanism do Aspirin and Ibuprofen utilize to produce their anti-inflammatory effects?

1. Inhibiting protein synthesis

2. Blocking histamine receptors

3. Inhibiting prostaglandin synthesis

4. Increasing cortisol levels

The correct answer is: Inhibiting prostaglandin synthesis

Aspirin and Ibuprofen are both classified as non-steroidal anti-inflammatory drugs (NSAIDs), and they exert their anti-inflammatory effects primarily through the inhibition of prostaglandin synthesis. Prostaglandins are lipid compounds that have several functions in the body, including promoting inflammation, pain, and fever. They are synthesized from arachidonic acid, which is released from cell membrane phospholipids by the action of the enzyme phospholipase A2. The key mechanism involves the inhibition of cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2. Aspirin irreversibly acetylates COX enzymes, blocking the conversion of arachidonic acid into prostaglandins. Ibuprofen, on the other hand, reversibly inhibits these enzymes. By reducing the levels of prostaglandins, both drugs effectively lower inflammation and alleviate pain. In contrast, inhibiting protein synthesis would affect a different biological process and is not the primary mechanism of action for these medications. Similarly, blocking histamine receptors is a mechanism more commonly associated with antihistamines, rather than the anti-inflammatory actions of aspirin and ibuprofen. Increasing cortisol levels relates to steroids and their anti-inflammatory effects, but