The mnemonic 'Pure As Gold' stands for which two purines?

• A. Adenine and Uracil
• B. Cytosine and Guanine
• C. Adenine and Guanine
• D. Thymine and Cytosine

Answer: (C)

The mnemonic "Pure As Gold" is used to remember the two purines found in nucleic acids: adenine and guanine. Purines are one of the two main types of nitrogenous bases, the other type being pyrimidines. In this mnemonic, "Pure" represents purines and the words "As Gold" correspond to adenine and guanine, respectively. This simple phrase helps students recall that both adenine and guanine share a similar double-ring structure characteristic of purines, distinguishing them from pyrimidines, which include cytosine, thymine, and uracil. Therefore, recognizing adenine and guanine as the purines highlighted in the mnemonic reinforces understanding of the structure and classification of nucleic acid components.