If there is 13% guanine in a DNA molecule how much cytosine and thymine would there be ?

13% cytosine

37% thymine

Explanation:

There are two types of nucleotides based on their structures - purines and pyrimidines.

The purines are adenine and guanine. The pyrimidines are thymine and cytosine.

Chargaff's rule states that the ratio of purines to pyrimidines in a molecule of DNA is 1:1

Therefore, the total number of A+G is the same at the total number of C+T.

All 4 bases together must equal 100% of the DNA molecule

If there is 13% guanine, and guanine always pairs with cytosine, there is also 13% cytosine.Together, that is 26% of the total sample.

100-26 = 74% of the total of adenine and thymine.

Since there are equal amounts of A and T, we know that the DNA sample is 74/2 = 37% thymine

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times

currents is the correct answer.