A growing E. coli cell of volume holds ATP at about and runs at a power of about .…
PHYSICS · Subjective · Fermi University Physics · Biophysics & Medical Physics · Physical foundations of the living cell · Physical foundations of the living cell
Life at Thermal Energy, Ch The scales of life and the thermal energy
Problem
A growing E. coli cell of volume 1fL holds ATP at about 3mM and runs at a power of about 10−12W. Splitting one ATP molecule under cellular conditions releases about 50kJmol−1. (a) List the assumptions needed to estimate how long the cell's stock of ATP would last if nothing replaced it. (b) Find the number of ATP molecules in the cell and the energy released by splitting one of them, in joules and in kBT at 298K. (c) Estimate, to one significant figure, how many ATP molecules the cell splits each second and how long the stock would last. (d) Compare that time with the rungs of the chapter's timescale ladder: how many times over must the cell rebuild its whole ATP stock during one twenty-minute division? Say whether the assumptions make the time too short or too long.