Final answer:
The cytosolic concentration of calcium ions (Ca²⁺) is kept low through the activity of ion pumps in the plasma membrane. Chelators like EDTA bind to calcium ions to maintain low cytosolic concentrations.
Step-by-step explanation:
The cytosolic concentration of calcium ions (Ca²⁺) is maintained at a low level through the activity of ion pumps in the plasma membrane. These pumps continuously remove calcium ions using adenosine-5'-triphosphate (ATP), which helps to keep the cytosolic concentration low. Calcium ions can also be stored in cytoplasmic vesicles like the endoplasmic reticulum or accessed from outside the cell for signaling purposes. Ligand-gated calcium ion channels allow higher levels of calcium ions to flow into the cytoplasm during signaling, raising the concentration. This increase in calcium ions can trigger specific responses depending on the cell type.
Chelators like EDTA play a role in maintaining low cytosolic calcium concentrations by binding to calcium ions. EDTA, for example, forms stable complexes with calcium ions, preventing them from interacting with other molecules in the cytosol. This helps to maintain a low cytosolic concentration of calcium ions.