Question

A sodium-potassium pump uses one ATP during each cycle. Imagine that 12 times per second a pump goes through a cycle of exporting three sodium ions and importing two potassium ions. How many glucose molecules does the cell break down by aerobic respiration to power this one pump for a minute? (Recall that aerobic respiration of one glucose molecule theoretically yields 36 ATP.)

Answer 1

Ans. #Step 1: Total pumping cycles = Pumping rate x Time

                                                = (12 cycles / sec) x 60 sec

                                                = 720 cycles

#Step 2: Total ATP consumed = ATP consumption rate per cycle x No. of cycles

                                                = (1 ATP / cycle) x 720 cycle

                                                = 720 ATP

#Step 3: Required number of Glucose molecules =

                                                Required amount of ATP / Theoretical ATP yield of glucose

                                                = 720 ATP / (36 ATP / glucose molecule)

                                                = 20 glucose molecules