Question

Given below are two statements:

Statement I: A unit formed by the attachment of a base to 1' position of sugar is known as nucleoside.

Statement II: When nucleoside is linked to phosphorous acid at 5 -position of sugar moiety, we get neucleotide.

In the light of the above statements, choose the correct answer from the options given below:

• A. Both Statement I and Statement II are false
• B. Statement I 1s true but Statement II is false
• C. Statement I is false but Statement II is true
• D. Both Statement I and Statement II are true

Answer 1

Answer: (B)

Statement I 1s true but Statement II is false

Answer 2

Statement I: A unit formed by the attachment of a base to the 1' position of sugar is known as a nucleoside. This statement is true. A nucleoside is indeed formed by the attachment of a nitrogenous base (e.g., adenine, guanine, cytosine, thymine, or uracil) to the 1' carbon of a sugar molecule (ribose or deoxyribose).
Statement II: When a nucleoside is linked to phosphoric acid at the 5'-position of the sugar moiety, we get a nucleotide. This statement is false. A nucleotide is formed when a nucleoside (base attached to sugar) is linked to a phosphoric acid (phosphate) molecule at the 5' carbon of the sugar moiety. However, the statement erroneously mentions "phosphorous acid" instead of phosphoric acid, which is incorrect.

Therefore, The correct option is (B): Statement I 1s true but Statement II is false.