# Calculating nucleotide percentages

1. Aug 28, 2014

### Medicol

1. A gene of length 4080 A° has 3120 hydrogen bonds. On one chromatid of one gene, there are 240 nucleotides of adenine, and 40% of total nucleotides are cytosine. Calculate each nucleotide percentage in the gene.

2. Relevant equations

3. Set L be the length of DNA, so $$L=\frac{N}{2}3.4$$
we then have $$N=2400$$.
Because $$C_1=G_2=0.4N=960$$
and $$A_1=T_2=240$$
we have $$A_2+C_2=1200$$
In a DNA we also have $$∑Hbonds=2A+3G=2(A_1+A_2)+3(G_1+G_2)=3120$$
or $$480+2A_2+3G_1+2880=3120$$
or $$2A_2+3G_1=-240$$

It's an incorrect approach...

Last edited: Aug 28, 2014
2. Aug 28, 2014

### Ygggdrasil

I suspect what the question tried to say here is that one strand of the gene (e.g. the coding strandt) has 240 nt of adenine and 40% of the total nts are cytosine. If that was what the questioner meant, chromatid is the incorrect term to use. I'd double check with whomever was the source of the question, however.