Question

You have approximately 1013 cells in your body (human cells, that is – we'll come back to the rest in a few weeks!). if all of those human cells arose by successive divisions of your original zygote, how many divisions did it take to produce you? determine the integral number of divisions that gives the closest result.

Answer 1

From the zygote cells differentiate by 2^n. Here n is the number of divisions needed to attain the total number of cells.

Here 2^n = 10^13 = 10000000000000

After 10 divisions = 2^n = 1024 (n = 10)

After 20 divisions = 2^20 = 1048576

After 30 divisions = 2^30 = 1073741824

After 40 divisions = 2^40 = 1099511627776

Almost after 43 divisions or 43.3 divisions = 10829260783553

Hence, about 43 divisions are needed to attain 10^13 cells.