Question

Which of the following is the best explanation for the inability of a specific animal cell to reduce the Ca₂⁺ concentration in its cytosol compared with the extracellular fluid?

Answer 1

A specific animal cell may be unable to reduce the Ca²⁺ concentration in its cytosol compared with the extracellular fluid due to ligand-gated calcium ion channels, cell-type specific responses, and the action of ion pumps.

Step-by-step explanation:

A specific animal cell may be unable to reduce the Ca²⁺ concentration in its cytosol compared with the extracellular fluid due to several factors:

1. The presence of ligand-gated calcium ion channels that allow higher levels of Ca²⁺ to flow into the cytoplasm, raising the cytoplasmic Ca²⁺ concentration.
2. The response to the increase in Ca²⁺ varies depending on the cell type involved. In some cell types, an increase in Ca²⁺ can lead to muscle contractions or release of insulin.
3. The action of ion pumps in the plasma membrane that continuously remove Ca²⁺ by using ATP, resulting in a low free concentration of Ca²⁺ within the cell.

These factors combined contribute to the inability of the specific animal cell to reduce the Ca²⁺ concentration in its cytosol compared to the extracellular fluid.