Question

A double-stranded piece of alien nucleic acid has been isolated. Each individual strand of the nucleic acid is 160 nucleotides long; for a total of 320 nucleotides in the isolated piece of nucleic acid. An initial analysis shows that of the 320 nucleotides, 95 contain the base uracil. How many nucleotides containing the base isoAdenine (iA) would be found in the isolated piece of double-stranded nucleic acid?

(A) 0
(B) 95
(C) 190
(D) 225
(E) cannot be determined

Answer 1

Answer:

The correct answer is option (B) "95".

Explanation:

Nucleic acids in double-stranded molecules follow certain rules for complementary bonding. In Earth's eukaryotic cells, adenine is attached to uracil and guanine is attached to cytosine. The proposed alien nucleic acids are not that different from Earth's nucleic acids, because isoAdenine (iA) could only be attached to uracil. Therefore, since the initial analysis shows that 95 of the 320 nucleic acids are uracil, 95 nucleotides containing the base isoAdenine (iA) would be found in the double-stranded molecule.