Carotenes, which have the chemical formula C_40 H_x, are synthesized by many pla
ID: 1055003 • Letter: C
Question
Carotenes, which have the chemical formula C_40 H_x, are synthesized by many plants, and are responsible for some of the bright colors found in red and orange fruits and vegetables, as well as all the orange colors in fall foliage. Lycopene, a carotene with the structure below, is responsible for the red color in tomatoes and watermelon. What would he a reasonable guess for the lambda_max of lycopene? Phytoene, a carotene with the structure below, absorbs light at 286 nm. When ingested, phytoene will accumulate in a variety of places in the body, including in the skin. Why would this molecule be beneficial in the skin? In the search window of MolView (at the top of the screen next to the magnifying glass), type "lycopene" and select the compound option. Select "Jmol" rightarrow "MEP surface opaque". Briefly, how would you describe the MEP surface of lycopene? In the search window of Mol View type "phytoene" and select the compound option. Select "Jmol" rightarrow "MEP surface opaque". Briefly, how would you describe the MEP surface of phytoene? In the Spectroscopy experiment you learned that the color of compounds has to do with the movement of electrons. Based on the structural and MEP surface differences between lycopene and phytoene, why is lycopene colored and phytoene colorless?Explanation / Answer
7. Conjugated and unconjugated moelcules
a. Lysopene with an extended conjugation is expected to have a lambda max of greater than 400 nm
b. Phytoene when present in skin protects the skin from UV radiation and acts as an antioxidants and antiinflamatory agent.
e. Phtoene has isolated sets of double bonds and no extended conjugation which results in a lower lambda mass value and does not show any color. On the other hand, lycopene has an extended conjugated structue of double bonds which makes higher lambda max and shows color for the compound.