Multiple Choice Questions (MCQs) on Eicosanoid Synthesis, Regulation, and Pharmacological Action with Explanations: Question 1: Which enzyme catalyzes the conversion of arachidonic acid to prostaglandin H2 (PGH2) in the cyclooxygenase pathway? a) Lipoxygenase b) Phospholipase A2 c) Cyclooxygenase-1 (COX-1) d) Cytochrome P450 Answer : c) Cyclooxygenase-1 (COX-1) Explanation: COX-1 is responsible for converting arachidonic acid to PGH2, the precursor of various prostaglandins. Question 2: Which class of eicosanoids is involved in promoting vasodilation, relaxation of vascular smooth muscle, and inhibition of platelet aggregation? a) Prostaglandins b) Leukotrienes c) Thromboxanes d) Lipoxins Answer : a) Prostaglandins Explanation: Prostaglandins play roles in vasodilation, relaxation of smooth muscle, and inhibition of platelet aggregation. Question 3: What role do lipoxins play in inflammation? a) They promote inflammation. b) They have anti-inflammatory and pro-resolving effects. c) The...