Question

Which of the following is an example of a primary metabolite?

• A. Antibiotics
• B. Alkaloids
• C. Amino acids
• D. Flavonoids

Hint:

• Primary metabolites are essential for basic life functions and growth (e.g., amino acids, sugars, ATP).
• Secondary metabolites are not essential for basic growth but often have specialized roles (e.g., antibiotics, toxins, pigments, alkaloids).

Answer 1

The Correct Option is C

Metabolites are classified as primary or secondary:

• Primary Metabolites: Directly involved in normal growth, development, and reproduction. Essential for cell survival. Produced during the active growth phase (trophophase). Examples include amino acids, nucleotides, simple sugars, organic acids of central pathways (like citric acid, pyruvate), lipids, vitamins, ethanol (from primary fermentation).
• Secondary Metabolites: Not directly involved in growth or reproduction but often have ecological roles or specialized functions. Production often occurs during stationary phase or under stress. Examples include antibiotics, alkaloids, toxins, pigments, steroids, flavonoids.

Let's analyze the options: (a) Antibiotics: Secondary metabolites. (b) Alkaloids (e.g., morphine, caffeine, nicotine): Secondary metabolites, often with pharmacological activity or defense roles. (c) Amino acids: The building blocks of proteins, essential for all living cells. They are primary metabolites. (d) Flavonoids: A large class of plant secondary metabolites, often pigments, with roles in signaling, defense, UV protection. Therefore, amino acids are primary metabolites. \[ \boxed{\text{Amino acids}} \]