Question

While looking at a cell under a microscope, a scientist is able to see a biological molecule. This molecule is a nucleic acid with double strands and contains the nitrogenous bases adenine, thymine, cytosine, and guanine. Based on this information, what conclusion can the scientist draw regarding this nucleic acid?

Answer 1

He/she would be able to conclude that due to the lack of uracil and presence of double strands that the molecule is DNA and not RNA.

Answer 2

Answer:

It is a DNA molecule (deoxyribonucleic acid).

Explanation:

There are only two types of nucleic acids in nature based on their structure and composition which are mentioned as under:

(1) DNA (Deoxyribonucleic acid)

(2) RNA (Ribonucleic acid)

A DNA molecule is characterized by double helix in which two strands which are anti parallel to each other are joined together with the help of interactions like hydrogen bonds which exist between the nitrogenous bases of these two strands. For example, adenine of one strand is joined with thymine of another strand by 2 hydrogen bonds (A=T) while cytosine of one strand is joined with guanine of another strand by 3 hydrogen bonds (C≡G). In contrast to this, an RNA molecule is single stranded therefore no such interactions exist in the RNA molecule.

Also, an RNA molecule does not have thiamine as nitrogenous base in it, instead of thiamine it has uracil.

Based on the above mentioned facts we can easily conclude that this nucleic acid is DNA.