Question

DNA differs from RNA only in
A. Only Sugars
B. Nitrogen base only
C. Nitrogen base and sugar
D. None of the above

Answer 1

Hint: Life on our planet is very diverse ranging from microscopic microorganisms to huge giant animals. All these organisms differ in their anatomy and physiology but are similar in their genetic constitution that is either they have RNA or DNA. Both have the same structure except a single difference in their chemical makeup.

Complete answer:
DNA and RNA are known as nucleic acids.
DNA is deoxyribonucleic acid which is the blueprint of the synthesis of proteins that encode different characteristics of an organism’s body. A DNA molecule consists of a set of instructions that are required for the growth, reproduction and development of an organism. They are the hereditary material which is passed on from one generation to the other by the process of reproduction. DNA molecules are made up of nucleotides which are composed of nitrogenous base, sugars group (deoxyribose in the case of DNA) and a phosphate group. Nitrogenous bases like guanine (G), cytosine (C), thymine (T), and adenine (A) are present in the DNA molecule and their arrangement denotes a genetic code.
RNA on the other hand is ribonucleic acid and it helps in the direct synthesis of proteins from the DNA. Its main work is to carry the instructions from DNA that are required for the synthesis of proteins. It is also composed of nucleotides, sugar groups (ribose sugar) and phosphate groups just like DNA but has different sugar groups and nitrogenous bases. Sugar group present in RNA is ribose whereas at the place of thymine (T) uracil (U) is present.
Thus, the right option is C.

Additional information:
- DNA has a double helical structure whereas RNA has a linear structure.
- The main function of DNA is to replicate itself and store genetic information that is converted by the RNA for the synthesis of proteins.
- The DNA molecule is much larger than the RNA molecule in length.
- Base pairing of guanine and cytosine is same in both the nucleic acids as G≡C but the pairing between the other nucleotides is different as in DNA A=T and in RNA A=U.

Note: The process of transfer of genetic information from the DNA to the RNA molecule is known as DNA transcription in which the base sequences present in the DNA are duplicated into the RNA molecule with the help of messenger RNA (mRNA).