A scientist who isolates and counts the number of nucleotides in its DNA molecule discovers that there are 2,893,963 molecules of guanine. How many molecules of the other three nucleotides are in the original DNA? I think I know the answer but could really use some help with this assignment for my Micro class.
2007-02-12 03:52:40 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Biology
Ok I guess I don't get it. My thinking was that if the bp is 4411529 and you minus the 2893963 of Guanine then you have 1517566 left, wouldn't you just half that and get the number of the A and T? I am confused.
2007-02-12 04:02:13 · update #1
I think I get it now. I think it would be 758,783 of both A and T? Does this sound correct to you guys? Thanks for your help guys.
2007-02-12 04:19:21 · update #2
OK...By standard base pairing rules, you know that G=C, so there will be the same number of cytosine nucleotides in the DNA.
Now, if the original DNA was 4411529 base pairs long, there are twice that many nucleotides (2 bases/each base pair). So, the total of A + T has to equal the total number of bases minus G+C.
The number of As and Ts will be half that, since they both have to be equal.
Hope this helps...
2007-02-12 03:58:57 · answer #1 · answered by hcbiochem 7 · 1⤊ 0⤋
To clarify the answer by hcbiochem (since you said you don't quite get it)...
4,411,529 is the number of base pairs (ie the number of nucleotides on a single strand of DNA)
2,893,963 is the total number of G in the genome (on both strands)
4,411,529 * 2 = 8,823,508 (total number of nucleotides in the genome)
8,823,508 = A + T + G + C
A=T
G=C=2,893,963
==>8,823,508 = A + A + 2,893,963 + 2,893,963
Solve for A.
2007-02-12 04:13:12 · answer #2 · answered by Shanna J 4 · 1⤊ 0⤋