MICROANATOMY

Detailed explanation-1: -The sarcomere is comprised of myofilaments, which overlap each other. Thick myofilaments consist of a protein called myosin and have enlarged portions called myosin heads. Thin myofilaments are made from a protein called actin and contain areas where the myosin heads can bind.

Detailed explanation-2: -The myofilaments include thick filaments, composed mainly of myosin, and thin filaments composed mainly of actin. The thick and thin filaments cause the cross-striations because of their regular overlap that is kept in register all across the diameter of the muscle fiber.

Detailed explanation-3: -Answer and Explanation: “Thick filaments are composed of actin.” This statement is false. Thin filaments (not thick) are made of actin protein subunits. Thick filaments are made of myosin proteins.

Detailed explanation-4: -Thick filament is made up of a protein called Myosin. Each myosin (thick filament) is made up of Many monomeric proteins called Meromyosins. Hence Major protein in the thick filaments of skeletal muscle fiber is Myosin. So, the correct answer is ‘Myosin’.

Detailed explanation-5: -The thick filaments are composed of myosin, and the thin filaments are predominantly actin, along with two other muscle proteins, tropomyosin and troponin. Muscular contraction is caused by the interaction between actin and myosin as they temporarily bind to each other and are released.