EVERYDAY SCIENCE

Detailed explanation-1: -Microfilaments are thin (7 nm) molecules composed principally of actin protein subunits, which polymerize to form elongated actin filaments (F-actin). Individual actin molecules, called G-actin, carry ATP to provide energy for the polymerization process.

Detailed explanation-2: -Microfilaments are composed of two strands of actin monomers twisted into helical filaments that have intrinsic polarity. All cells, including neurons, have a microfilament-rich, mesh-like network on the cytoplasmic side of the plasma membrane.

Detailed explanation-3: -The two proteins found on actin filaments are troponin and tropomyosin. Troponin has three subunits and serves as a regulatory protein by providing a site for calcium binding. Tropomyosin provides an anchoring place for troponins and covers the site on actin where myosin usually binds.