Regarding transpo of Ca++ across a membrane, which of the following is true?

Calcium transpo occurs by secondary active transpo. Hence, option A is incorrect It is an antipo or counter transpo; occurring as Na+/ Ca++ exchanger. Hence, option B is incorrect It is primarily aimed at maintaining a low cytosolic Ca++. Thus, option C is incorrect. To maintain a low intracytoplasmic Ca++, calcium is extruded out of the cell or pumped out from cytosol into the endoplasmic reticulum. Ca2+ ATPase - The enzyme that transpos Ca2+ out of the cytoplasm and into the sarcoplasmic reticulum of muscle cells. These are called P-type ATPases because they form a key phosphorylated intermediate.