MDCAT Biology MCQ #840

When examining the nitrogenous bases of DNA, a student identifies Adenine and Guanine. What structural feature characterizes these purines compared to pyrimidines?

MDCAT Biology MCQ #840

  1. Question 1

    Q1. When examining the nitrogenous bases of DNA, a student identifies Adenine and Guanine. What structural feature characterizes these purines compared to pyrimidines?

    • A) Single-ring structure
    • B) Triple-ring structure
    • C) Open-chain structure
    • D) Double-ring structure

    Answer: Double-ring structure

    Explanation: Purines (Adenine, Guanine) consist of a double-ring structure, while pyrimidines (Cytosine, Thymine, Uracil) consist of a single-ring structure.