Final answer:
The major contractile protein found within skeletal muscle is myosin, which forms thick filaments and interacts with actin to cause muscle contraction. Proteins like troponin and tropomyosin regulate this interaction, but myosin is the protein responsible for the contraction itself.
Step-by-step explanation:
The major contractile protein found within skeletal muscle is myosin. This protein, along with actin, plays a crucial role in the process of muscle contraction, specifically in the sliding filament model of muscle contraction. Myosin forms the thick filaments of the myofibrils, while actin forms the thin filaments. During muscle contraction, myosin heads attach to binding sites on the actin filaments and pull them closer together, which shortens the muscle fiber and produces force.
It is important to note that other proteins like troponin and tropomyosin are regulatory proteins that control the interaction between myosin and actin by responding to calcium ions (Ca++). Troponin changes shape upon binding with Ca++, which moves tropomyosin away from the binding sites on actin and allows for the myosin heads to attach. However, myosin is the protein that actually engages in the contractile movement.
Therefore, the answer to the question "Which of the following is a major contractile protein found within skeletal muscle?" is C) Myosin.