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Muscular system Knowledge-Based Practice

Biology · Human Body & Physiology · Biology · Support & Movement

5 Biology practice questions on Muscular system. Questions that assess core concepts and understanding.

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Questions

  1. 1.

    In skeletal muscle fibers, which molecule acts as an immediate high-energy phosphate donor to rapidly regenerate ATP from ADP during the onset of vigorous contraction?

    • A) Glycogen
    • B) Creatine phosphate
    • C) Lactic acid
    • D) Myoglobin
  2. 2.

    During excitation-contraction coupling in skeletal muscle fibers, what is the primary role of calcium ions released into the sarcoplasm from the sarcoplasmic reticulum?

    • A) Hydrolyzing ATP bound to the myosin head to energize the cocked state
    • B) Activating voltage-gated sodium channels along the sarcolemma to propagate an action potential
    • C) Binding to troponin to shift tropomyosin away from the myosin-binding sites on actin
    • D) Activating acetylcholine receptors at the motor end plate to initiate depolarization
  3. 3.

    In skeletal muscle fibers, which structure conducts action potentials from the sarcolemma deep into the cell interior to trigger contraction?

    • A) Transverse tubules (T-tubules)
    • B) Sarcoplasmic reticulum
    • C) Intercalated discs
    • D) Myosin myofilaments
  4. 4.

    During the cross-bridge cycle of skeletal muscle contraction, what is the direct consequence of ATP binding to the myosin head?

    • A) It triggers the power stroke that pulls the actin filament toward the center of the sarcomere.
    • B) It causes the myosin head to detach from the actin filament.
    • C) It exposes the myosin-binding sites on the actin filament by displacing tropomyosin.
    • D) It stimulates the release of calcium ions from the sarcoplasmic reticulum into the sarcoplasm.
  5. 5.

    According to the sliding filament model of skeletal muscle contraction, which of the following events occurs within a sarcomere during contraction?

    • A) The length of the A band decreases significantly.
    • B) The distance between adjacent Z lines increases.
    • C) The width of the H zone and the I band decreases.
    • D) The thick myosin filaments shorten while thin actin filaments remain unchanged.

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