Ribose and 2-deoxyribose have an important role in biology. Among the most important derivatives are those with phosphate groups attached at the 5 position. Mono-, di- and tri-phosphate forms are important, as well as 3-5 cyclic monophosphates. Purines and pyrimidines form an important class of compounds with ribose and deoxyribose. When these purine and pyrimidine derivatives are coupled to a ribose sugar, they are called nucleosides. Answer the following questions : (a) What products would be formed when DNA is hydrolysed ? How is DNA different from RNA with reference to a structure ? (b) Differentiate between nucleotide and nucleoside. (c) (i) Mention two important functions of nucleic acid. OR (c) (ii) Name the linkage which joins two nucleotides. Name the base that is found in nucleotide of RNA but not in DNA.

Year	Paper Code	Set	Position
CBSE 2025	Series 56-4	Set 1	Question 30
CBSE 2025	Series 56-4	Set 2	Question 29
CBSE 2025	Series 56-4	Set 3	Question 30

• Step 1: Stating the fundamental formula / law statement (+1 Mark)
• Step 2: Intermediate mathematical substitution or proof steps (+1 Mark)
• Step 3: Correct final value or conclusion with mandatory SI units (+1 Mark)