Which of the following statements are correct regarding muscle proteins ?
(i) Actin is a thin filament and is mde up to two F-actin
(ii) The complex protein, tropomyosin is distributed at regular intervals on the troponin
(iii) Myosin is a thick filament which is also a polymerised protein.
(iv) The globular head of meromyosin consists of light meromyosin (LMM).

Options

A. (i), (ii) and (iii)
B. (i), (ii) and (iv)
C. (i) and (iii)
D. (ii) and (iv)

Answer

C

Explanation

Each actin (thin) filament is made of two 'F' (filamentous) actin helically wound to each other. Each F actin is a polymer of monomeric 'G' (globular) actins. Myosin (thick) filament is a polymerised protein. Many monomeric proteins called meromyosins constitute one thick filament. Tropomyosin is a fibrous molecule that attached to F actin in the groove between its filament. The globular head of meromyosin consisit of heavy meromoysin.