Question

a scientist discovers a species of bacteria. the relative percentage of adenine base in its dna is about 23%. what is the expected percentage for the other three bases?
thymine %; guanine %; cytosine %

Explanation:

Step1: Apply Chargaff's rule for adenine - thymine

According to Chargaff's rule, in DNA, the amount of adenine (A) is equal to the amount of thymine (T). Given that \(A = 23\%\), so \(T=23\%\).

Step2: Calculate the sum of guanine and cytosine

Since \(A + T+G + C=100\%\), substituting \(A = 23\%\) and \(T = 23\%\), we get \(23\%+23\%+G + C=100\%\). Then \(G + C=100\%-(23\% + 23\%)=54\%\).

Step3: Apply Chargaff's rule for guanine - cytosine

Also, by Chargaff's rule, the amount of guanine (G) is equal to the amount of cytosine (C). So \(G=\frac{G + C}{2}=\frac{54\%}{2}=27\%\) and \(C = 27\%\).

Answer:

thymine \(23\%\), guanine \(27\%\), cytosine \(27\%\)