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GATE 2022 BT – Question 22

General Biology · Biochemistry: Biomolecules, biological membranes, channels and pumps, molecular motors, action potential and transport · 1 mark · Multiple choice

Terpenoids are made of ___________ units

  1. amino acid
  2. carbohydrate
  3. isoprene
  4. triacylglycerol

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Show answer and explanation

Correct answer: (C) isoprene

Explanation

Terpenoids (isoprenoids) are a large class of natural products such as menthol, carotenoids, steroids and rubber.

They are built from the five-carbon **isoprene** unit ($CH_2=C(CH_3)-CH=CH_2$), which in cells comes from isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). Joining two, three or four units gives monoterpenes (C10), sesquiterpenes (C15) and diterpenes (C20).

Answer **isoprene** (C).