Question

Chlorosis is produced in the leaves due to the deficiency of Fe, Mg, Mn, S or N. Of these essential elements, those that are exclusive constituents of the chlorophyll molecule are

• A. Fe, S.
• B. N, S.
• C. Mg, S.
• D. Mg, N.

Answer 1

Answer: (D)

Mg, N.

The chlorophyll molecule is composed of a porphyrin ring. This is also known as the chlorin ring. There are nitrogen molecule in every prophyrin ring. It is the essential component of the pigment. This porphyrin ring structure is also present in heme. There is magnesium ion present in the centre of the ring. This binding of the magnesium ion makes the stable structure of the chlorophyll molecule. Deficiency of these minerals results in deficiency of the chlorophyll molecule which results in chlorosis and decrease in the rate of photosynthesis.

Thus, the correct answer is option D.