MICROANATOMY

Detailed explanation-1: -Actin is the thin filaments of the muscles. They are a polymer of G-actin monomers arranged in chains and two such chains are wound in a helix. So, the given statement is true.

Detailed explanation-2: -Actin filaments (F-actin) are linear polymers of globular actin (G-actin) subunits and occur as microfilaments in the cytoskeleton and as thin filaments, which are part of the contractile apparatus, in muscle and nonmuscle cells (see contractile bundles).

Detailed explanation-3: -Actin. The thin filament consists of two intertwined bands of actin monomers. Both skeletal and cardiac forms of actin are present during human cardiac development.

Detailed explanation-4: -The Major Components of the Thin Filament: Actin, Tropmyosin, Troponin Complex and Nebulin. The thin filament is the main site of Ca+2 regulation and is composed of four components in striated muscle: actin, TM and troponin (Tn) with its three subunits [25] (Figure 5).

Detailed explanation-5: -Most of the cytoplasm consists of myofibrils, which are cylindrical bundles of two types of filaments: thick filaments of myosin (about 15 nm in diameter) and thin filaments of actin (about 7 nm in diameter).