Molecular Biology Of The Cell 6th Edition by Bruce Alberts, Alexander Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter

Exercise 15

Which statements are true? Explain why or why not.
-"Diffusion" sounds slow-and over everyday dis- tances it is-but on the scale of a cell it is very fast. The aver- age instantaneous velocity of a particle in solution-that is, the velocity between the very frequent collisions-is where T = temperature in K and m = mass in g/molecule. Calculate the instantaneous velocity of a water molecule (molecular mass = 18 daltons), a glucose mol- ecule (molecular mass = 180 daltons), and a myoglobin molecule (molecular mass = 15,000 daltons) at Just for fun, convert these numbers into kilometers/hour. Before you do any calculations, try to guess whether the molecules are moving at a slow crawl (<1 km/hr), an easy walk (5 km/hr), or a record-setting sprint (40 km/hr).