myofilament anatomy

What are the repeating units called in which myofilaments are arranged?

• Z discs

• Actin

• Myosin

• Sarcomeres

What does the H zone contain?

• No filaments

• Only thick filaments

• Both thick and thin filaments

• Only thin filaments

Which protein blocks myosin-binding sites on actin when the muscle is relaxed?

• G-actin

• Tropomyosin

• Myosin

• Troponin

What is the role of the M line?

• Attachment site for thin filaments

• Contains only thin filaments

• Attachment site for thick filaments

• Marks the boundary of a sarcomere

Which of the following structures has the active sites to which the heads of the thick filament will bind?

• g-actin

• myosin

• tropomyosin

• troponin

• f-actin