A primary transcript (immature, non-processed) single-stranded RNA molecule has the following nucleotide composition: 30% A, 20% G, 24% C, and 26% U. What is the nucleotide composition of the double-stranded DNA molecule from which it was transcribed

Answer: The nucleotide composition of the double-stranded DNA molecule from which it was transcribed is 30% T, 20% C, 24% G, and 26% A.

Explanation: RNA is transcribed from DNA in the process of transcription. The single stranded RNA is complementary to the DNA template strand. In DNA base pairing, adenine pairs with thymine while guanine pairs with cytosine, this means that in a double-stranded DNA molecule, the total number of adenine is equal to the number of thymine while the total number of guanine is equal to the total number of cytosine.

In RNA, adenine pairs with thymine, guanine pairs with cytosine while uracil pairs with adenine. This means that the total number of thymine on the DNA template strand is equal to the total number of adenine on the RNA strand, the total number of guanine on the DNA template strand is equal to the total number of cytosine on the RNA strand, the total number of adenine on the DNA template strand is equal to the total number of uracil on the RNA strand while the total number of cytosine on the DNA template strand is equal to the total number of guanine on the RNA strand.

RNA strand = DNA strand

30% A = 30% T

20% G = 20% C

24% C = 24% G

26% U = 26% A