Which protein forms the thick filament in muscle?

Which protein forms the thick filament in muscle?

• A. Actin
• B. Titin
• C. Myosin
• D. Nebulin

Answer: (C)

The thick filament is formed by myosin. Myosin molecules bundle together with their long tails and project globular heads outward; those heads grab onto binding sites on the actin thin filaments and, using energy from ATP, pull to shorten the sarcomere during contraction. Actin makes up the thin filament, not the thick one. Nebulin helps stabilize and align actin, while titin acts as an elastic spring that helps keep filaments in place and contributes to passive elasticity. So, the protein forming the thick filament is myosin.

The thick filament is formed by myosin. Myosin molecules bundle together with their long tails and project globular heads outward; those heads grab onto binding sites on the actin thin filaments and, using energy from ATP, pull to shorten the sarcomere during contraction. Actin makes up the thin filament, not the thick one. Nebulin helps stabilize and align actin, while titin acts as an elastic spring that helps keep filaments in place and contributes to passive elasticity. So, the protein forming the thick filament is myosin.