Nucleic acids are mainly of two types: deoxyribonucleic acids (DNA) and ribonucleic acids (RNA). A nucleotide is composed of a base, a C5-carbohydrate and phosphate group, which are bonded in the sequence base–carbohydrate–phosphate. The carbohydrate molecule in DNA is \(\beta\)-D-2-deoxyribose, whereas in RNA it is \(\beta\)-D-ribose. DNA contains four bases, viz. two purine bases adenine and guanine and two pyrimidine bases cytosine and thymine. RNA also contains four bases: the same two purine bases adenine and guanine and two pyrimidine bases cytosine and uracil (in the place of thymine). In nucleic acids the nucleotides are joined together by phosphodiester linkage between 5′ and 3′ carbon atoms of the pentose sugar. The secondary structure of DNA shows that two nucleotide chains run in opposite directions and form a right-handed helix in which the two strands are held together by hydrogen bonds at definite distances. The double helix of DNA is the storehouse of the hereditary information of the organism. The process in which a DNA molecule is copied to give an identical DNA molecule is known as replication.
The genetic information of a cell is passed on to the newly formed (daughter) cells by
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → DNA
The passage states that the double helix of DNA is the storehouse of the hereditary information of the organism, and that a DNA molecule is copied to give an identical DNA molecule in replication.
During cell division the DNA molecule duplicates itself and identical DNA strands pass to the daughter cells, so the genetic information is passed on through DNA.
RNA molecules synthesise proteins, but the message for each protein is present in DNA.
NCERT (2026-27 edition):
10.5.3 Biological Functions of Nucleic Acids – “DNA is the chemical basis of heredity and may be regarded as the reserve of genetic information. … A DNA molecule is capable of self duplication during cell division and identical DNA strands are transferred to daughter cells.”