Question

$\dfrac{{{\text{AT}}}}{{{\text{GC}}}}$ ratio in human being is:
A. $0.93:1$
B. $1:0.9$
C. $1.52:1$
D. $0.93:2$

Answer 1

Hint: Nucleic acids are macromolecules present in all living cells in combination with protein with high concentration of basic amino acids to form nucleoproteins. They are information carrying compounds. A denotes Adenine, T denotes Thymine, G denotes Guanine and C denotes Cytosine.

Complete step by step answer:
Nucleic acids are of two types-DNA and RNA. Nucleotides are the monomers of nucleic acids. The nucleotides are derivatives of heterocyclic, highly basic purines and pyrimidines present in RNA and DNA. The molecule with no phosphate group is called nucleoside.
The carbon and nitrogen atoms in the parent structures are conventionally numbered to facilitate the naming and identification of the many derivative compounds. There are five types of nucleotide bases. They are adenine, guanine, cytosine, thymine and uracil. Adenine and guanine are the derivatives of purine. Cytosine, thymine and uracil are the derivatives of pyrimidines.
The nitrogenous bases in DNA pair up and form hydrogen bonds: adenine with thymine and guanine with cytosine. This is called complementary base pairing. It can occur between two RNA molecules or between parts of the same molecule. In RNA, thymine is replaced by uracil.
In a double stranded DNA, the amount of purine nucleotides is equal to the amount of pyrimidine nucleotides.
i.e. $\dfrac{{\left[ {\text{A}} \right] + \left[ {\text{T}} \right]}}{{\left[ {\text{G}} \right] + \left[ {\text{C}} \right]}} \sim 1$
But the ratio of $\dfrac{{{\text{AT}}}}{{{\text{GC}}}}$ is equal to $1.52:1$

So, the correct answer is Option C .

Note:
Nucleic acids are long polymers of nucleotides. Nucleotides are the basic building blocks of nuclei acids. Nucleotides contain five carbon sugars, a weakly basic nitrogenous compound and one or more phosphate compounds. Purines and pyrimidines have strong absorbance of UV light.