Which statement about the molecular arrangement of actin and myosin in myofibrils is true?
A) A thin filament consists of myosin and tropomyosin.
B) Two chains of myosin monomers are twisted into a helix.
C) Two strands of tropomyosin lie in the grooves of the myosin.
D) Troponin forms the head of the myosin molecule.
E) The myosin heads have ATPase activity and interact with the actin.

Question

Quizplus · Accepted Answer

The myosin heads have ATPase activity and interact with the actin. This statement is true because myosin heads contain ATPase activity, which allows them to break down ATP to provide energy for muscle contraction. Additionally, myosin heads interact with the actin filaments in a way that causes the filaments to slide past each other, resulting in muscle contraction. The other statements are false: A) Thin filaments consist of actin and tropomyosin, not myosin and tropomyosin. B) Myosin monomers are filaments that contain two heavy chains twisted into a helix, not two chains of myosin monomers. C) Tropomyosin lies over the actin filament, not in the grooves of the myosin. D) Troponin is a regulatory molecule that binds to tropomyosin, not the head of the myosin molecule.

Which Statement About the Molecular Arrangement of Actin and Myosin