The component that houses a high concentration of Ca²⁺ and releases it to trigger muscle contraction is:

Question

Quizplus · Accepted Answer

The sarcoplasmic reticulum is a specialized organelle in muscle cells that stores and releases Ca2+ ions, which are essential for muscle contraction. The Ca²⁺ in the question likely refers to Ca2+ ions (S is used to indicate ionization, and P is often used to indicate chemical bonds such as phosphate bonds). Therefore, the sarcoplasmic reticulum is the most likely answer. B, C, D, and E are all structures involved in muscle contraction, but they do not directly release Ca2+ ions. The sarcomere is the contractile unit of muscle fibers, the t-tubules are invaginations of the sarcolemma that allow for the rapid spread of action potentials, the sarcolemma is the plasma membrane of the muscle cell, and troponin is a protein that regulates muscle contraction by interacting with Ca2+ ions.

The Component That Houses a High Concentration of Ca2+ and Releases

The Component That Houses a High Concentration of Ca²⁺ and Releases