Question

The genome of a newly-isolated member of the Proteobacteria has been completely sequenced and its genome size determined to be 5.5 Megabase pairs. A broth culture of this Proteobacteria has been grown to a density of 2 x 108 cells per mL in a 5-mL volume. Estimate the total amount of DNA in the culture, express your answer in kilometers, then describe this total DNA length in terms of a symbol on the log scale below (yellow star, black heart, green square, etc.) You may assume that there is exactly one copy of the genome per cell and that each base pair contributes 0.34 nm to the genome length.

Answer 1

The answer is given below.

Step-by-step explanation:

So, length of DNA of one cell = Distance between each base pair x No. of base pairs in each cell

= 0.34 x 10^-9 x 2.35 x 10^6

= 0.799 x 10^-3

= 7.99 x 10^-4 m

No. of cells per ml = 2 x 10^8 cells per ml

Total volume of culture = 5 ml

So, total length of DNA in 5ml culture

= Length of DNA of one cell x Total no. of cells per ml x total volume of culture

= 7.99 x 10^-4 x 2 x 10^8 x 5

= 79.9 x 10​​​​​​^4 m (1OOO m = 1 km)

= 79.9 x 10 km

= 799 km

so, total length of DNA present in 5ml culture equal to 799 km.