Question

Calceum ions are diffusing across the membrane of the sarcoplasmic rectilium. is the cell beginning contraction or ending contraction

a. True
b. False

Answer 1

True. Calcium ions are actively transported out of the sarcoplasmic reticulum during muscle contraction, initiating muscle contraction.

Step-by-step explanation:

Calcium ions are actively transported out of the sarcoplasmic reticulum during muscle contraction. The release of calcium ions from storage in the sarcoplasmic reticulum initiates muscle contraction.

When the positive sodium ions enter the muscle fiber and trigger an action potential, calcium channels in the membrane of the adjacent sarcoplasmic reticulum open, causing calcium ions to diffuse out and into the sarcoplasm. The arrival of calcium ions in the sarcoplasm initiates muscle contraction.

Therefore, the correct answer is True.