MDCAT Chemistry MCQ #4865

Analysis of a double-stranded DNA sample shows that Adenine makes up 20% of the nitrogenous bases. What is the percentage of Guanine in this sample?

MDCAT Chemistry MCQ #4865

  1. Question 1

    Q1. Analysis of a double-stranded DNA sample shows that Adenine makes up 20% of the nitrogenous bases. What is the percentage of Guanine in this sample?

    • A) 20%
    • B) 40%
    • C) 30%
    • D) 60%

    Answer: 30%

    Explanation: According to Chargaff's rule, A=T (20%) and G=C. Since A+T=40%, G+C must be 60%, making G equal to 30%. Option B is the percentage of Thymine.