- Following are certain statements regarding terpene class of secondary metabolites in plants:
A. Isopentenyl diphosphate and its isomer combine to form larger terpenes.
B. Diterpenes are 20 carbon compounds.
C All terpenos are derived from the union of 4 carbon elements.
D. Pyrothroids are monoterperie esters.
Which one of the following combination of above statements is correct?
(1) A, B and C
(2) A, B and D
(3) B, C and D
(4) A, C and D
Correct answer: (2) A, B and D
Explanation:
-
(A) is true: Isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP) combine as building blocks to form larger terpenes by sequential condensation.
-
(B) is true: Diterpenes are composed of 20 carbon atoms, formed from four isoprene units.
-
(C) is false: Terpenes are derived from 5-carbon isoprene units, not 4-carbon elements.
-
(D) is true: Pyrethroids, synthetic analogs of pyrethrins, are esters of monoterpenes (monoterpene esters).
Option-wise:
-
(1) A, B and C — C incorrect.
-
(2) A, B and D — correct.
-
(3) B, C and D — C incorrect.
-
(4) A, C and D — C incorrect.
Terpenes are synthesized by condensation of 5-carbon isoprene units like IPP and DMAPP forming larger compounds such as 20-carbon diterpenes, with pyrethroids representing monoterpene ester derivatives widely used as insecticides, demonstrating the biochemical diversity and ecological importance of terpenes in plants.
