What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?
When a nucleotide from DNA containing thymine is completely hydrolysed, it yields three products: thymine (the nitrogenous base), β-D-2-deoxyribose (the pentose sugar), and phosphoric acid.
A nucleotide is formed when a nucleoside (base attached to sugar at 1′ position) is linked to phosphoric acid at the 5′ position of the sugar moiety. In DNA, the sugar component is specifically β-D-2-deoxyribose. Upon complete hydrolysis, all these bonds are broken, releasing the individual components.
Explanation
According to the textbook section 10.5.1, complete hydrolysis of DNA yields a pentose sugar, phosphoric acid, and nitrogen-containing heterocyclic compounds (bases). For DNA specifically, the sugar moiety is β-D-2-deoxyribose. The context also clarifies that DNA contains four bases including thymine (T). The structure of a nucleotide (Fig. 10.5) shows it consists of a base attached to sugar at 1′ position, with phosphoric acid at 5′ position. Hydrolysis breaks these linkages to release the three constituent molecules.
Solution Steps
Step 1: Identify that a nucleotide consists of three components - a nitrogenous base, a pentose sugar, and phosphoric acid.
Step 2: For DNA, identify the specific sugar as β-D-2-deoxyribose.
Step 3: Since the nucleotide contains thymine, identify the base as thymine.
Step 4: Conclude that hydrolysis yields: thymine + β-D-2-deoxyribose + phosphoric acid.