The protein molecule contains 950 nucleotides with cytosine, accounting for 20% of the total number of nucleotides in this DNA.

The protein molecule contains 950 nucleotides with cytosine, accounting for 20% of the total number of nucleotides in this DNA. Determine the percentage of other nucleotides that make up the DNA molecule. How long is this snippet?

We use Chargaff’s rules.
1) C = G = 20%
2) (A + T) = 100 – (20 + 20) = 60%, so A = T = 30%
3) To calculate the number of these nucleotides, we make up the proportion:
20% – 950
30% – X
X = 1425
4) to determine the length of DNA, you need to find out how many nucleotides are contained in one chain:
(950 + 950 + 1425 + 1425): 2 = 2375, then 2375 x 0.34 = 808 (nm).
Answer: A = T = 30%, G = C = 20%, fragment length – 808 nm.