Which of the following observations is part of the evidence supporting the Watson-Crick structure of DNA?
A) In the DNAs examined from a wide variety of sources, the adenine and cytosine contents are equal.
B) A non-virulent pneumococcus can be transformed to a virulent strain by the addition of DNA.
C) RNA is susceptible to hydrolysis by alkali, whereas DNA is not.
D) The sum of the purines present in any double-stranded DNA is equal to the sum of the pyrimidines present.

Question

Quizplus · Accepted Answer

The observation that the sum of the purines (adenine and guanine) present in any double-stranded DNA is equal to the sum of the pyrimidines (thymine and cytosine) present supports the Watson-Crick structure of DNA. This is because the Watson-Crick model predicts that the two strands of DNA are complementary, meaning that adenine pairs with thymine and guanine pairs with cytosine, resulting in equal amounts of purines and pyrimidines.

Which of the Following Observations Is Part of the Evidence