Question 77: Given below are two statements :
Statement I : A unit formed by the attachment of a base to 1^{\prime} position of sugar is known as nucleoside
Statement II : When nucleoside is linked to phosphorous acid at 5^{\prime}-position of sugar moiety, we get nucleotide.
In the light of the above statements, choose the correct answer from the options given below :
(1) Statement I is true but Statement II is false.
(2) Statement I is false but Statement II is true.
(3) Both Statement I and Statement II are true.
(4) Both Statement I and Statement II are false.
Answer: Option (1)
Explanation:
A nucleoside is formed when a nitrogenous base is attached to the
1^{\prime} carbon atom of a pentose sugar, such as ribose or deoxyribose.
Thus, Statement I is correct.
A nucleotide is formed when a nucleoside is linked to a phosphate group,
specifically phosphoric acid, at the 5^{\prime} position of the sugar.
Statement II is incorrect because it mentions phosphorous acid instead of phosphoric acid.
Therefore, Statement I is true but Statement II is false, making option (1) the correct answer.