Question

Which of the following secondary metabolites are used as pigments?
(i) Carotenoids
(ii) Ricin
(iii) Morphine
(iv) Anthocyanin
(v) Abrin
(vi) Rubber

• A. (i) and (v)
• B. (ii) and (vi)
• C. (i) and (iv)
• D. (iii) and (v)

Answer 1

Answer: (C)

In addition to primary metabolites, there are many other small molecules, specific to the particular type of cells, are called secondary metabolites. More appropriately, their direct role or exact function is not known yet in many cases. Their exact vitality for cells or body remains a mystery for scientists. Many of these metabolites are useful for humans, and certain secondary metabolites have ecological importance. Many of them are obtained from vascular plants. The examples of secondary metabolites are as follows:

• antibiotics, spices, scents, essential oils,
• polymeric substances like rubber, gums, cellulose
• lectins such as concanavalin A
• pigments like carotenoids, anthocyanins
• alkaloids like morphine, codeine
• terpenoids like mono-, diterpenes
• toxins like abrin, ricin

Carotenoids are plant pigments predominantly present in algae, and photosynthetic bacteria. More than 600 different types of carotenoids have been observed and studied so far and they impart yellow, red, and orange colors in plants, vegetables, and fruits. These are the potent antioxidants used by humans.
Anthocyanins are flavanoids that are water-soluble pigments imparting red, purple, blue color. These are present in berrries-blueberry, raspberry, black rice, and black soybean etc. These are also used as potent antioxidants.