Question

online unit 4 retake: dna, replication, & protein synthesis
consider chargaffs rules (base - pair rules). if a sample of dna contains 30% adenine, how much guanine does it have?
10%
20%
30%
40%

Explanation:

Step1: Apply Chargaff's rule

In DNA, \(A = T\) and \(G = C\), and \(A+T + G + C=100\%\). Given \(A = 30\%\), then \(T=30\%\).

Step2: Calculate \(G + C\)

\(G + C=100\%-(A + T)=100\%-(30\%+30\%) = 40\%\).

Step3: Find \(G\)

Since \(G = C\), \(G=\frac{G + C}{2}=\frac{40\%}{2}=20\%\).

Answer:

20%