Ücretsiz Kullanmaya Başla
PDF Downloads

Muscle contraction

Biology • Support & Movement • Knowledge-Based • 5 questions

Muscle contraction Knowledge-Based Download PDF

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

5 Biology practice questions on Muscle contraction. Questions that assess core concepts and understanding.

Questions

  1. 1.

    During the cross-bridge cycle of skeletal muscle contraction, which specific biochemical event directly triggers the power stroke that pulls the actin filament toward the center of the sarcomere?

    • A) The hydrolysis of ATP into ADP and inorganic phosphate
    • B) The binding of a new ATP molecule to the myosin head
    • C) The influx of sodium ions across the sarcolemma
    • D) The release of inorganic phosphate from the myosin head
  2. 2.

    In skeletal muscle fibers, which of the following best describes the primary function of the transverse tubules (T-tubules) during excitation-contraction coupling?

    • A) Conducting action potentials from the sarcolemma deep into the interior of the muscle fiber to stimulate calcium release from the sarcoplasmic reticulum
    • B) Actively transporting calcium ions from the sarcoplasm into the extracellular fluid to trigger muscle relaxation
    • C) Synthesizing and storing ATP molecules necessary for the detachment of myosin heads
    • D) Anchoring the thin actin filaments to maintain sarcomere alignment during filament sliding
  3. 3.

    According to the sliding filament theory of skeletal muscle contraction, which of the following regions of the sarcomere remains constant in length during contraction?

    • A) I band
    • B) H zone
    • C) A band
    • D) Distance between consecutive Z lines
  4. 4.

    During the cross-bridge cycle of skeletal muscle contraction, which event directly causes the myosin head to detach from the actin filament?

    • A) Binding of a new ATP molecule to the myosin head
    • B) Hydrolysis of ATP into ADP and inorganic phosphate
    • C) Release of inorganic phosphate from the myosin head
    • D) Active pumping of calcium ions back into the sarcoplasmic reticulum
  5. 5.

    During the contraction of a skeletal muscle fiber, which of the following events occurs directly as a result of calcium ions binding to troponin?

    • A) Tropomyosin shifts its position, exposing the myosin-binding sites on the actin filament.
    • B) ATP binds directly to actin filaments to trigger the power stroke of the cross-bridge cycle.
    • C) Acetylcholine is released from the sarcoplasmic reticulum into the surrounding sarcoplasm.
    • D) The thick filaments shorten in length, causing a noticeable reduction in the width of the A band.