Question

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current attempt in progress
put these events associated with the excitation - contraction coupling reaction in the correct chronological sequence:

1. action potentials are generated along the sarcolemma of the muscle fiber.
2. binding sites on actin are uncovered, allowing myosin to bind and carry out power strokes.
3. ca^{++} ions bind to troponin
4. ca^{++} is released from the sarcoplasmic reticulum.
5. dhp receptors are activated
6. ryanodine receptors are activated

1,5,6,4,3,2
1,6,5,2,4,3
5,6,4,3,2,1
6,5,4,2,3,1

Explanation:

• The process starts with the generation of action potentials along the sarcolemma (1).
• This activates DHP receptors (5).
• DHP receptor activation leads to ryanodine receptor activation (6).
• Ryanodine receptor activation causes \(Ca^{++}\) release from the sarcoplasmic reticulum (4).
• \(Ca^{++}\) binds to troponin (3).
• This uncovers binding sites on actin for myosin to bind and carry out power strokes (2).

Answer:

1, 5, 6, 4, 3, 2