While the above steps are occurring, calcium is actively pumped back into the sarcoplasmic reticulum.

Pyruvate from glycolysis is actively pumped into mitochondria.

This protein, known as uncoupling protein 1 (thermogenin), facilitates the return of the protons after they have been actively pumped out of the mitochondria by the electron transport chain.

Conversely, membranes are not permeable to potassium, so this ion must be actively pumped into the cell.

This happens because sodium ions (Na+) are pumped actively out of the cell, while potassium (K+) ions are pumped in until they are unevenly distributed between the two compartments.

Practical spent fuel pool designs generally do not rely on passive cooling but rather require that the water be actively pumped through heat exchangers.

There is a system of internal tubes and sacs through which gases diffuse or are actively pumped.

They are specialised in scavenging solutes from those in the cell walls that are actively pumped requiring energy.

Thus, a problem in high blood potassium can be resolved somewhat without jettisoning too much of what is sometimes a dangerously scarce mineral that can not be pumped actively independently from sodium.

HCO ions are made from CO outside the cell by another carbonic anhydrase and are actively pumped into the cell by a membrane protein.