Question

Nucleic acids are polymers of :

• A. amino acids
• B. nucleosides
• C. nucleotides
• D. pentose sugar

Hint:

Remember the hierarchy: Sugar + Base = Nucleoside; Nucleoside + Phosphate = Nucleotide; Nucleotide \(\times\) n = Polynucleotide (Nucleic Acid).

Answer 1

The Correct Option is C

Concept:

• Nucleic acids, such as DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid), are the biological macromolecules essential for all forms of life.

• These are long-chain polymers called polynucleotides.

• A polymer is built from repeating structural units known as monomers.

• In the case of nucleic acids, these monomeric units consist of three distinct chemical components: a nitrogenous base, a pentose sugar, and a phosphate group.
Step 1: Identify the monomeric unit
The fundamental building block of a nucleic acid is the nucleotide.
A nucleotide is formed when a phosphate group is attached to the \( 5' \)-position of the sugar moiety of a nucleoside.

Step 2: Analyze the polymer structure
Nucleotides are joined together by phosphodiester linkages between the \( 5' \) and \( 3' \) carbon atoms of the pentose sugar residues.
This repeating sequence of sugar-phosphate-sugar-phosphate forms the backbone of the nucleic acid chain.

Step 3: Distinguish between options
(A) Amino acids are the monomers for proteins.
(B) Nucleosides consist of only a sugar and a base (lacking the phosphate needed for polymerization).
(D) Pentose sugar is just one component of the nucleotide.

Step 4: Conclusion
Since nucleic acids are made of repeating nucleotide units linked together, they are defined as polymers of nucleotides. The final answer is nucleotides.