To determine the percentage of adenine in a DNA sample where 15 of the bases are thymine, we can start by recalling that DNA is made up of four types of nucleobases: adenine (A), thymine (T), cytosine (C), and guanine (G). In the DNA double helix, adenine pairs with thymine, meaning that the amount of adenine should equal the amount of thymine for the DNA to remain stable.
Given that there are 15 thymine bases, we can conclude that there are also 15 adenine bases in the sample. To find the percentage of adenine, we first need to know the total number of bases in the sample. Since we currently only have the information for thymine and adenine, and assuming no information about cytosine and guanine, we can express the total number of bases as:
Total Bases = Adenine + Thymine + Cytosine + Guanine
If we only consider adenine and thymine, the total would be:
Total Bases = 15 (A) + 15 (T) = 30
Now, to find the percentage of adenine:
Percentage of Adenine = (Adenine / Total Bases) * 100
Plugging in the numbers:
Percentage of Adenine = (15 / 30) * 100 = 50%
Therefore, the percentage of the bases in the sample that are adenine is 50%.