A bioprocess reactor needs 1013 cells to generate the desired amount of product. If you started the reactor with a single cell, how many generations (one generation is the process in which 1 cell divides into two cells) are needed to get 1013 cells? If a human cell divides once every 18 h and a bacterium divides once every 60 min, how long will it take to attain the desired cell number in the bioreactor for each type of cell? A human body has only 1015 cells, and according to this calculation, an adult should develop relatively quickly compared to what it takes in reality. Why do you suppose this does not happen?