Assume that the cells in a microbial culture are spherical with an average diameter of $1m,$ and that the density of the cells is approximately the same as water $).$ The cells are $80\%$ water and $90\%$ of the dry weight is organic $($i$.$e$.,$ organic material that volatilizes to $C{O}^2$ at $550C).$ Determine the volume and the organic mass of one cell $($in units of grams of volatile suspended solids, VSS$).$ How many cells are present in one liter of solution of the culture if the organic dry weight is $400mg$ VSS$/$L$?.$

If the total number of metabolically active bacteria is $3\mathrm{.}2{10}^{12}$ cells per liter, what percentage of the total number of cells is active cells? Hint: the final

Round your answer for the percent active cells to the nearest whole percent and don't enter the $"\%"$ symbol $($e$.$g$.,$ if the answer were $50\mathrm{.}4\%,$ enter $"50").$ Email me a copy of your calculations by before the exam deadline $(11$:$59$ pm Sunday$)$ for partial credit $($Excel calculations are accepable also$).$