Question

Estimates of the number of cells in the human body vary over an order of magnitude. Indeed, the precise number varies from one individual to another and depends on whether you count bacterial cells. Here is one way to make an estimate.

a) Assume that an average cell has a diameter of 6 micrometers (6 x 10-6 meter), which means it has a volume of 100 cubic micrometers. How many cells are there in a cubic centimeter?

b.) Estimate the number of cells in a liter, using the fact that a cubic centimeter equals a milliliter.

c.) Estimate the number of cells in a 70-kilogram (154-pound) person, assuming that the human body is 100% water (actually it is about 60 - 70% water) and that 1 liter of water weighs 1 kilogram.

Answer 1

Estimates of the number of cells in the human body vary over an order of magnitude. Indeed, the precise number varies from one individual to another and depends on whether you count bacterial cells. Here is one way to make an estimate