Question

A sample of DNA is collected from an organism. It is analyzed and determined that 20% of the DNA is made up of the base adenine. Using this information, determine the amount of the three remaining bases for this sample.

Answer 1

The correct answer is -

Thymine: 20%

Guanine: 30%

Cytosine: 30%

Step-by-step explanation:

According to Chargaff's rule which states that the purine residues are equal to the pyrimidines residue in DNA sample which means A+G = T+C where A is adenine, G is guanine, C is cytosine and T is thymine. It is also known that A is always equal to T and C is equal to G.

So, A+G+T+C = 100

20+20+G+C

100-40 = G+C

60= G+C

as we know G is equal to C similarly A is equal to T

Thus, G = C= 30%

A= T= 20%