Question

Which of the following bases is not found in RNA?
A. Thymine
B. Uracil
C. Adenine
D. Guanine

Answer 1

Hint: RNA (Ribonucleic acid) is the single stranded biological molecule. It helps in the synthesis of proteins. Four nitrogenous bases present in RNA are: adenine, uracil, guanine and cytosine. Thymine is more stable than uracil which makes the DNA more stable than RNA.

Complete answer:
DNA (deoxyribonucleic acid) is the genetic material. It is made up of sugar, phosphate group and nucleotide bases. Adenine, thymine, guanine and cytosine are four nitrogenous bases present in DNA. RNA (ribonucleic acid) is an important biological macromolecule. It is single stranded. It also consists of sugar, phosphate groups and nitrogenous bases. Adenine, uracil, guanine and cytosine are present in RNA molecules. Uracil is present in place of thymine in the RNA. Uracil is less energy expensive than thymine. Uracil is formed by chemical degradation of cytosine IN DNA, so having thymine as the normal is base. This phenomenon helps in detection and repair of such incipient mutations more efficiently. It plays a very important role in protein synthesis.
Thymine is more stable than uracil thus making the DNA more stable than RNA. It has a greater resistance to photochemical mutations.
From the above information we have found that thymine is not found in RNA.

Hence, the correct answer is option (A).

Note: If uracil is present in the DNA, it will result in mutagenic U: G mispairs, and misincorporation of Dump. It gives a less harmful U: A pair. Removal of uracil can be done by glycosylases. In RNA adenine is always paired with uracil because uracil replaces the thymine. Purins (A and G) bind with pyrimidines (T, U and C) with the help of hydrogen bond. DNA has two poly-nucleotide sequences.