Question

There are three blanks in the following statement. Mark the correct option having suitable words for filling the blanks. The thin filaments of myofibril contain ………’a’………..actin and two filaments of ……….’b’………..protein along with……….’c’……..protein for masking binding site for
myosin–

• A.

  	'a'	'b'	'c'
  (A)	1 F	Troponin	Tropomyosin

• B.

  	'a'	'b'	'c'
  (B)	1 F	Tropomyosin	Troponin

• C.

  	'a'	'b'	'c'
  (C)	2 F	Troponin	Tropomyosin

• D.

  	'a'	'b'	'c'
  (B)	2 F	Tropomyosin	Troponin

Answer 1

The correct option is D

	'a'	'b'	'c'
(B)	2 F	Tropomyosin	Troponin

Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other.

Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length.

A complex protein troponin is distributed at regular intervals on the tropomyosin. In the resting state a subunit of troponin masks the active binding sites for myosin on the actin filaments.

Thin filaments of myofibril contain two filaments of actin and two filaments of troponin, along with tropomyosin protein.
So, the correct option is 'a - 2F, b - troponin c - Tropomyosin'.