Question

Calcium ions are stored in _____________ in a muscle fibre.

• A. mitochondria
• B. sarcoplasmic reticulum
• C. golgi bodies
• D. all of the above

Answer 1

The correct option is B sarcoplasmic reticulum

Calcium ions are stored inside sarcoplasmic reticulum. Now, when muscle action potential travels along the sarcolemma, the sarcoplasmic membrane opens up the calcium channels leading to the release of calcium ions. This results in movement of calcium ions into the sarcoplasm around thick and thin filaments. The calcium ion then binds with troponin which causes a change in its shape which after a series of events finally results in muscle contraction.
Mitochondrion is the cell organelle that is involved in ATP production.
Golgi bodies are cell organelles that help process and package proteins and lipid molecules.