It is during G1 phase that a a cell release cdks to initiate the events for cell division. At this stage, b<span>iochemical triggers known as </span>cyclin-dependent kinases<span> (Cdks) switch on cell cycles events at the corrected time and in the correct order to prevent any mistakes.</span>
Here is a diagram I found online if it helps!
Answer:
because it is moving Na+ against its concentration gradient