What Organelle Wraps and Surrounds the Myofibril and Stores Calcium

Question

What organelle wraps and surrounds the myofibril and stores calcium?
A) cross bridge
B) sarcomere
C) sarcolemma
D) sarcoplasmic reticulum

Accepted Answer

The sarcoplasmic reticulum is an organelle that wraps and surrounds the myofibril in muscle cells. It is responsible for storing and regulating the release of calcium ions during muscle contraction. Choice A (cross bridge) refers to the connection between the thick and thin filaments in a sarcomere, while Choice B (sarcomere) and Choice C (sarcolemma) are structures within the muscle cell but do not specifically wrap and store calcium.