Question

The correct sequence is action potential in the muscle membrane; depolarization of the T tubules; release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; cross-bridge formation; and splitting of adenosine triphosphate (ATP).

1) Depolarization of the T tubules; release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; cross-bridge formation; and splitting of adenosine triphosphate (ATP)
2) Action potential in the muscle membrane; depolarization of the T tubules; release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; cross-bridge formation; and splitting of adenosine triphosphate (ATP)
3) Release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; cross-bridge formation; and splitting of adenosine triphosphate (ATP)
4)epolarization of the T tubules; release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; and splitting of adenosine triphosphate (ATP)

Answer 1

The correct sequence is "Action potential in the muscle membrane; depolarization of the T tubules; release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; cross-bridge formation; and splitting of adenosine triphosphate (ATP)" so the correct option is option 2) Action potential in the muscle membrane; depolarization of the T tubules; release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; cross-bridge formation; and splitting of adenosine triphosphate (ATP).

Step-by-step explanation:

The sequence of events leading to muscle contraction is a highly coordinated process. It begins with an action potential in the muscle membrane, which triggers the depolarization of the T tubules.

This depolarization signals the release of Ca²⁺ from the sarcoplasmic reticulum (SR), a crucial step in muscle contraction. The released Ca²⁺ then binds to troponin C, a regulatory protein on the actin filaments.

This binding of Ca²⁺ initiates the cross-bridge formation between actin and myosin, leading to muscle contraction. Finally, the energy for muscle contraction is provided by the splitting of adenosine triphosphate (ATP).

Option 2 accurately reflects this chronological order of events. The action potential initiates the cascade, followed by T tubule depolarization, SR Ca²⁺ release, Ca²⁺ binding to troponin C, cross-bridge formation, and ATP splitting.

This sequence ensures the precise and controlled contraction of muscle fibers, highlighting the importance of each step in the physiological process of muscle contraction.

The correct sequence is "Action potential in the muscle membrane; depolarization of the T tubules; release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; cross-bridge formation; and splitting of adenosine triphosphate (ATP)" so the correct option is option 2) Action potential in the muscle membrane; depolarization of the T tubules; release of Ca²⁺ from the sarcoplasmic reticulum (SR); binding of Ca²⁺ to troponin C; cross-bridge formation; and splitting of adenosine triphosphate (ATP).