In a double-stranded DNA sample, adenine constitutes 16% of the total number of bases - VCE - SSCE Chemistry - Question 4 - 2012 - Paper 1

In double-stranded DNA, the bases pair specifically: adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C). This means that the percentage of adenine will be equal to the percentage of thymine, and the percentage of guanine will be equal to the percentage of cytosine.

Given that adenine constitutes 16% of the total number of bases, thymine also constitutes 16%. Therefore, the total percentage of adenine and thymine is:

$16\% + 16\% = 32\%$

Since the total percentage of all four bases (A, T, G, C) must equal 100%, the combined percentage of guanine and cytosine is:

$100\% - 32\% = 68\%$

Given that guanine and cytosine are equal:

$G + C = 68\% ext{ and } G = C$

Thus, the percentage of guanine is:

$G = \frac{68\%}{2} = 34\%$

Therefore, the percentage of guanine content in the double strand is 34%.