In Certain Kinds of Muscle Cells, Calcium Ions are Stored

Question

In certain kinds of muscle cells, calcium ions are stored in_________ .
A) the rough ER
B) the smooth ER
C) both smooth and rough ER
D) the cytoplasm

Accepted Answer

Calcium ions are stored in specialized regions of the smooth endoplasmic reticulum called the sarcoplasmic reticulum in muscle cells.