Question

If 15% of a particular DNA strand are nucleotides containing cytosine, what percentage of the DNA molecule would contain thymine

Answer 1

35%

Step-by-step explanation:

To make a DNA helix, two DNA strands are required. They are connected by the nitrogenous bases on each strand. Each type of nitrogenous base is complementary to another type: cytosine (pyrimidine) pairs with guanine (purine) and thymine (pyrimidine) pairs with adenine (purine). This means they only bond with their pair.

For every cytosine, there must be a guanine bonded to it. So, if 15% of the strand is cytosine, another 15% must be guanine.

Since,

15% + 15% = 30% and 100% - 30% = 70% ,

30% of the DNA strand consists of the cytosine-guanine pair and 70% of the DNA strand consists of the adenine-thymine pair.

Since,

70% / 2 = 35% ,

70% is made up of equal parts adenine and thymine, 35% of the DNA strand must contain thymine.