Question

A protein transports an ion across the cell membrane against its concentration gradient. Which of the following must be true?

The ion pump is moving the ion from high to low concentration.

The ion is being moved from the inside to the outside of the cell.

The ion is being transported without chemical energy.

The ion pump is using active transport to move the ion.

Answer 1

The ion pump is using active transport to move the ion.

Step-by-step explanation:

When a protein transports an ion across the cell membrane against its concentration gradient, the ion pump is using active transport to move the ion.

Active transport (via the ion pump) is characterized by the movement of substances and ions against the concentration gradient, that is, it always occurs from places where they are less concentrated to places where they are more concentrated. This process is possible thanks to the presence of certain proteins in the plasma membrane that, with the expenditure of energy, are able to combine with the substance or ion and transport it to the region where it is most concentrated. For this to happen, the protein undergoes a change in its shape to receive the substance or ion. It is important to note that the energy required for this change comes from the breakdown of the ATP (adenosine triphosphate) molecule into ADP (adenosine diphosphate) and phosphate.