Actin and myosin are proteins. Protein is a broad category of molecules.
myosin molecules
Most myosin molecules are composed of both a head and a tail domain.
Thick - it is the length of myosin.
true
Actin and myosin are the molecules used for muscle contraction.
true
Ca2+
ATP (--> ADP+Pi) and actin
Regulatory molecules are commonly types of proteins which will regulate the functions of the muscles. The interaction of actin and myosin is regulated which will trigger muscle contraction.
Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
ATP not ADP binds to actin-myosin and is cleaved by to ADP.