試題詳解

71. Which of the following is the CORRECT sequence that occurs during the excitation and contraction of a muscle cell? 1. Calcium is released and binds to the troponin complex. 2. Tropomyosin shifts and unblocks the cross-bridge binding sites. 3. Transverse tubules depolarize the sarcoplasmic reticulum. 4. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP. 5. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane.
(A) 2, 1, 3, 5, 4
(B) 2, 1, 3, 4, 5
(C) 5, 3, 2, 4, 1
(D) 5, 3, 1, 2, 4
(E) 5, 3, 2, 1, 4