# There are 880 G-nucleotides in the DNA molecule, which is 22% of the total number of nucleotides. Determine the number

**There are 880 G-nucleotides in the DNA molecule, which is 22% of the total number of nucleotides. Determine the number of remaining nucleotides in this molecule and the length of this molecule?**

1) Find the total number of nucleotides in the DNA molecule:

880 guanyl nucleotides corresponds to 22%,

x – 100%, x = 4000 nucleotides (A + T + G + C).

2) According to Chargaff’s rule (G = C) of cytidyl nucleotides in a molecule is 880, and the amount of adenyl and thymidyl nucleotides is calculated as follows:

4000 – (880 + 880) = 2240: 2 = 1120 nucleotides.

3) There are 4000 nucleotides in a molecule. One turn contains 10 pairs of nucleotides, its length is 3.4 nm, which means that the total number of turns is 4000: 20 = 200. Then the length of the molecule is 3.4 nm * 200 = 680 nm.