Question

Select the correct option regarding $A,B$ and $C$.

• A. A-Tropomyosin-runs close to F-actin throughout its length
• B. B-Troponin-complex protein distributed at regular interval of tropomyosin
• C. C-F actin - polymer of monomeric G-actin helically bound to each other
• D. None of these

Answer 1

Answer: (B)

B-Troponin-complex protein distributed at regular interval of tropomyosin
Filamentous actin (-actin) is the major protein of muscle thin filaments, and actin microfilaments are the main component of the eukaryotic cytoskeleton. Tropomyosin also binds to -actin in smooth muscle and in non-muscle cells and stabilizes and regulates the filaments there in the absence of troponin. It coils around the actin filament.

Troponin is a component of thin filaments (along with actin and tropomyosin), and is the protein complex to which calcium binds to trigger the production of muscular force. It is distributed throughout the complex in periodic distribution.

As actin monomers (G-actin) bind together, they form an actin filament (F-actin), which has a helical structure.

So the correct answer should be option B.