Locomotion and Movement · NEET Preparation Zoology
Which sequence correctly describes the initiation of skeletal muscle contraction after a nerve impulse reaches the neuromuscular junction?
Practice question from Locomotion and Movement (NEET Preparation Zoology), with the correct answer and a step-by-step solution.
medium · MCQ · Q-3C2AAB
Which sequence correctly describes the initiation of skeletal muscle contraction after a nerve impulse reaches the neuromuscular junction?
- A.Calcium ions bind to tropomyosin, which exposes the active sites on myosin.
- B.Calcium ions bind to troponin, causing tropomyosin to move away from the active sites on actin.Correct answer
- C.ATP binds to actin and exposes the active sites on tropomyosin.
- D.Acetylcholine directly binds to myosin and causes actin filaments to shorten.
Solution
The nerve impulse releases acetylcholine, which ultimately causes calcium ions to be released from the sarcoplasmic reticulum. Calcium binds to troponin, shifting tropomyosin and exposing myosin-binding sites on actin.
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