Plants rely not only on primary metabolites like lipids, carbohydrates, and amino acids to grow, but also on a vast array of secondary metabolites which help them function in their specific ecological context. These specialized compounds often mediate interactions with other organisms—attracting pollinators or beneficial microbes, or deterring herbivores and pathogens through bitter flavors, toxic effects, or other defensive properties. Among all secondary metabolites, terpenes form the largest and most diverse group, representing roughly 55% of the specialized chemicals produced across the plant kingdom. Despite their prominence, the terpene synthases of the TPS‑a clade—which are thought to shape much of the chemical identity of lettuce—remain poorly understood. In this work, I set out to uncover the function of these enzymes by biochemically characterizing TPS‑a gene candidates from Lactuca sativa. Biochemical characterization involves determining which chemical product a given gene helps to make. This is accomplished by replicating the enzyme’s reactions—either in a living organism or in a test tube—and then examining the resulting molecules to see what was produced. The observed products begin to shed light on how lettuce assembles its distinctive terpene chemistry and opens new avenues for exploring how these compounds contribute to plant ecology, defense, and agricultural improvement.