Chapter 25.16, Problem 27P

Interpretation Introduction

Interpretation:

The isoprene units has to be marked in lycopene and $\text{β-carotene}$.

Concept Introduction:

Terpenes are made by joining five-carbon units, usually in a head to tail-fashion.

Monoterpenes are those terpenes with two isoprene units-have 10 carbons, sesquiterpenes have 15 carbons, diterpenes have 20 carbons, triterpenes have 30 carbons and tetraterpenes have 40 carbons.

Isopentenyl pyrophosphate is the five-carbon compound used for the biosynthesis of terpenes.

According to the isoprene rule, the isoprene units are terpenoids joined by head to tail linkage or 1-4-linkage.