Question

Chlorophyll consists of
A. A head of phytol and tail of four pyrrole rings
B. A head of linked carbons and tail of four pyrrole rings
C. A head of four pyrrole rings and tail of linked nitrogen
D. A head of four pyrrole rings and an alcoholic phytol tail

Answer 1

Hint: Chlorophyll is a class of greenish colored pigment that is responsible for trapping light energy to carry out photosynthesis. The basic structure of chlorophyll has four Pyrrole rings and a long carbon chain.

Complete answer:
Option A: Phytol is a diterpenoid long-chain alcohol. They are a constituent of chlorophylls. But they do not act as the head of chlorophyll structure. Also, the pyrrole rings are not the tail of chlorophyll. Therefore, this is the incorrect option.
Option B: The head of chlorophyll molecules doesn't consist of linked carbons. Therefore, this is the incorrect option.
Option C: Linked nitrogen chains are not a part of the chlorophyll molecule structure. Therefore, this is the incorrect option.
Option D: Chlorophyll structure consists of two parts. A head of four pyrrole rings and an alcoholic phytol tail. The four pyrrole rings interconnected through their alpha carbon via methine bridges constitute a porphyrin ring. Their four nitrogen atoms will coordinately bind to a central magnesium atom. The structure known as the fifth ring of chlorophyll is a chlorin ring. This is usually associated with the long phytol chain. The structure slightly varies from type to type, but the basic structure remains the same. In most plants, chlorophyll is derived from glutamate. Chlorophyll is bound with proteins and via them, they transfer the harvested light energy to the required directions.

Hence, the correct answer is option (D)

Note: 1.The structure of chlorophyll is very similar to that of hemoglobin.
2.In heme, the central atom is iron instead of magnesium.