Question

cross - bridges form between the ____ and the ____. multiple choice troponin tropomyosin calcium sodium sarcoplasm sarcoplasmic reticulum

Explanation:

In muscle contraction, cross - bridges form between myosin and actin. Myosin has heads that bind to actin filaments to generate force for muscle movement. None of the provided options (troponin - tropomyosin are regulatory proteins; calcium and sodium are ions; sarcolemma and sarcoplasmic reticulum are parts of the muscle cell structure) are correct for cross - bridge formation. But if we assume the last option was meant to be myosin and actin, that is the correct pair for cross - bridge formation.

Answer:

None of the given options are correct. Cross - bridges form between myosin and actin.