Alkaloids are Basic, or Alkaline Molecules

Question

Alkaloids are basic, or alkaline molecules. Which is not a type of alkaloid?
A) Caffeine
B) Nicotine
C) Morphine
D) Quinine
E) Tannin

Accepted Answer

Tannin is not an alkaloid; it is a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds. Alkaloids, on the other hand, are naturally occurring compounds that contain mostly basic nitrogen atoms, which include caffeine, nicotine, morphine, and quinine.