Answer:
The percentage of thymine in a sample of the DNA will be 12%.
Structure of DNA:
The DNA, according to Chargaff, is made up of nucleotide subunits. These nucleotides are hydrogen-bonded to one another to form the double stranded molecule of DNA.
The nucleotides found in the DNA molecule are as follows:
Adenine
Thymine
Cytosine
Guanine
Adenine (A) pairs with Thymine (T) while Guanine (G) pairs with Cytosine (C).
Based on Chargaff's rule, the amount of adenine is equal to that of thymine in a DNA molecule. The same applies to Guanine and Cytosine. However, the total amount of nucleotides equals 1 or 100%.
A + T + G + C = 100%.
If cytosine makes up 38% of the DNA sample, this means that guanine will also be 38%.
G (38) + C (38) = 76%
100% - 78% = 24%
This means that Adenine and Thymine amounts to 24%. The amount of each nucleotide will be 24% ÷ 2 = 12% i.e. A = T = 12%
Therefore, the percentage of thymine in a sample of the DNA will be 12%.
Step-by-step explanation: